Terminal, wireless communication method, base station and system

Abstract

A terminal according to one aspect of the present disclosure comprises: a reception unit for receiving downlink control information (DCI) that, from among a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied, indicates a port for the second DMRS; and a control unit for controlling reception or transmission of the second DMRS, wherein the size of second information for indicating the port for the second DMRS is larger than the size of first information for indicating the port for the first DMRS. This embodiment of the present disclosure makes it possible to use an appropriate number of DMRS ports.

Description

[Technical Field]

[0001] The present disclosure relates to a terminal and a wireless communication method in a next-generation mobile communication system. 、 base station and systems Regarding. [Background technology]

[0002] In Universal Mobile Telecommunications System (UMTS) networks, Long Term Evolution (LTE) has been specified with the aim of achieving higher data rates and lower latency (Non-Patent Document 1). Also, LTE-Advanced (3GPP Rel. 10-14) has been specified with the aim of achieving higher capacity and more advanced features than LTE (Third Generation Partnership Project (3GPP (registered trademark)) Release (Rel.) 8, 9).

[0003] Successor systems to LTE (e.g., 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 or later) are also being considered. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)”, April 2010 Summary of the Invention [Problem to be solved by the invention]

[0005] In future wireless communication systems (e.g., NR), a beam management technique is being introduced. For example, in NR, beam formation (or utilization) in at least one of a base station and a user terminal (User Equipment (UE)) is being considered.

[0006] On the other hand, for layer orthogonalization and other purposes, multi-port reference signals (e.g., demodulation reference signals (DMRS)) are used. Future wireless communication systems will be required to have a greater number of DMRS ports than the existing specifications. However, there has been little progress in studying how to increase the number of DMRS ports. If an appropriate number of DMRS ports cannot be used, there is a risk that communication throughput / communication quality will deteriorate.

[0007] Therefore, the present disclosure provides a terminal using an appropriate number of DMRS ports, a wireless communication method, and 、 base station and systems One of the aims is to provide [Means for solving the problem]

[0008] A terminal according to one embodiment of the present disclosure includes a receiver that receives downlink control information (DCI) indicating a port for a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied, and a controller that controls reception or transmission of the second DMRS, and emotion News One value is the above No. 1DMRS For one or more port and one or more ports for the second DMRS. . [Effects of the Invention]

[0009] According to one aspect of the present disclosure, any suitable number of DMRS ports may be used. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows an example of an existing DMRS port table for DMRS configuration type 1. [Figure 2] FIG. 2 shows an example of an existing DMRS port table for DMRS configuration type 2. [Figure 3] 3A to 3D show an example of a 4 / 6 length FD-OCC. [Figure 4] FIG. 4 shows an example of a length-4 FD-OCC. [Figure 5] FIG. 5 shows an example of an existing DMRS port table for DMRS configuration type 1. [Figure 6] FIG. 6 shows a first example of a new DMRS port table for DMRS configuration type 1. [Figure 7] FIG. 7 shows a second example of a new DMRS port table for DMRS configuration type 1. [Figure 8] FIG. 8 shows a third example of a new DMRS port table for DMRS configuration type 1. [Figure 9] FIG. 9 shows an example of a new DMRS port table for DMRS configuration type 2. [Figure 10] FIG. 10 shows an example of an antenna port table according to option 1. [Figure 11] FIG. 11 shows an example of an antenna port table according to option 2. [Figure 12] FIG. 12 shows an example of an offset instruction according to option 2. [Figure 13] FIG. 13 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of the configuration of a base station according to an embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of the configuration of a user terminal according to an embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. [Figure 17] FIG. 17 is a diagram illustrating an example of a vehicle according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Beam Management) In NR, a beam management technique has been introduced. For example, in NR, forming (or using) a beam in at least one of a base station and a UE is being considered.

[0012] By applying beam forming (BF), it is expected that the difficulty of ensuring coverage due to the increase in carrier frequency will be alleviated and radio wave propagation loss will be reduced.

[0013] BF is a technology that uses, for example, a massively multi-element antenna to form a beam (antenna directivity) by controlling the amplitude / phase of a signal transmitted or received from each element (also called precoding). Note that Multiple Input Multiple Output (MIMO) using such massively multi-element antennas is also called massive MIMO.

[0014] Beam sweeping may be performed on both the transmitting and receiving sides to select an appropriate pair from multiple patterns of candidate transmitting and receiving beam pairs. A pair of transmitting and receiving beams may be called a beam pair and may be identified as a beam pair candidate index.

[0015] In addition, in beam management, instead of using a single beam, beam control at multiple levels such as a rough beam and a fine beam may be performed.

[0016] BF can be classified into digital BF and analog BF, which may be called digital precoding and analog precoding, respectively.

[0017] Digital BF is a method of performing precoding signal processing (on digital signals) at the baseband. In this case, parallel processing such as inverse fast Fourier transform (IFFT), digital-to-analog converter (DAC), and radio frequency (RF) is required for the number of antenna ports (or RF chains). On the other hand, it can form beams at any timing, as many times as the number of RF chains.

[0018] Analog beamforming is a method that uses a phase shifter on the RF, for example. Although analog beamforming cannot form multiple beams at the same time, it can be easily configured and implemented at low cost because it only rotates the phase of the RF signal.

[0019] A hybrid beamforming configuration that combines digital and analog beamforming is also possible. The introduction of massive MIMO is being considered for NR, but if a huge number of beamforming operations were to be performed using only digital beamforming, the circuit configuration would become expensive, so the use of a hybrid beamforming configuration is also envisioned.

[0020] (TCI, spatial relations, QCL) In NR, it is being considered to control the reception processing (e.g., at least one of reception, demapping, demodulation, and decoding) and transmission processing (e.g., at least one of transmission, mapping, precoding, modulation, and encoding) of at least one of a signal and a channel (which may be expressed as signal / channel; hereinafter, "A / B" may also be interpreted as "at least one of A and B") based on the transmission configuration indication state (TCI state).

[0021] The TCI state may represent that which is applied to a downlink signal / channel, and the equivalent of the TCI state which is applied to an uplink signal / channel may be expressed as a spatial relation.

[0022] The TCI state is information about the Quasi-Co-Location (QCL) of signals / channels, and may also be called spatial reception parameters, spatial relation information (SRI), etc. The TCI state may be configured in the UE for each channel or signal.

[0023] A QCL is an index that indicates the statistical properties of a signal / channel. For example, if a signal / channel has a QCL relationship with another signal / channel, it may mean that it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameter (e.g., spatial Rx parameter) is the same between these different signals / channels (i.e., they are QCLs with respect to at least one of these).

[0024] The spatial reception parameters may correspond to a reception beam (e.g., a reception analog beam) of the UE, and the beam may be determined based on a spatial QCL. A QCL (or at least one element of a QCL) in the present disclosure may be replaced with an sQCL (spatial QCL).

[0025] A plurality of types (QCL types) of QCLs may be defined. For example, four QCL types A and B may be provided, each having different parameters (or parameter sets) that can be assumed to be the same. The parameters (which may also be referred to as QCL parameters) are listed below: QCL Type A: Doppler shift, Doppler spread, mean delay and delay spread, QCL Type B: Doppler shift and Doppler spread, QCL Type C: Doppler shift and mean delay, · QCL Type D: Spatial receiving parameters.

[0026] Types A to C may correspond to QCL information related to synchronization processing of at least one of time and frequency, and type D may correspond to QCL information related to beam control.

[0027] The assumption by a UE that a given Control Resource Set (CORESET), channel, or reference signal is in a specific QCL (e.g., QCL type D) relationship with another CORESET, channel, or reference signal may be referred to as a QCL assumption.

[0028] The UE may determine at least one of a transmit beam (Tx beam) and a receive beam (Rx beam) for a signal / channel based on the TCI condition or QCL assumption of the signal / channel.

[0029] The TCI state may be, for example, information about the QCL between a target channel (or a Reference Signal (RS) for the channel) and another signal (e.g., another Downlink Reference Signal (DL-RS)). The TCI state may be set (indicated) by higher layer signaling, physical layer signaling, or a combination thereof.

[0030] In the present disclosure, higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, and the like, or a combination thereof.

[0031] The MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. The broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0032] The physical layer signaling may be, for example, Downlink Control Information (DCI).

[0033] The channel for which the TCI state is set (designated) may be, for example, at least one of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), and an uplink control channel (Physical Uplink Control Channel (PUCCH)).

[0034] Furthermore, the RS (DL-RS) that has a QCL relationship with the channel may be, for example, at least one of a Synchronization Signal Block (SSB), a Channel State Information Reference Signal (CSI-RS), and a Sounding Reference Signal (SRS). Alternatively, the DL-RS may be a CSI-RS (also called a Tracking Reference Signal (TRS)) used for tracking, or a reference signal (also called a QRS) used for QCL detection.

[0035] An SSB is a signal block that includes at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). An SSB may also be referred to as an SS / PBCH block.

[0036] A TCI state information element ("TCI-state IE" in RRC) configured by higher layer signaling may include one or more pieces of QCL information ("QCL-Info"). The QCL information may include at least one of information about a DL-RS having a QCL relationship (DL-RS relationship information) and information indicating a QCL type (QCL type information). The DL-RS relationship information may include information such as an index of the DL-RS (e.g., an SSB index, a Non-Zero-Power (NZP) CSI-RS resource identifier), an index of a cell in which the RS is located, and an index of a Bandwidth Part (BWP) in which the RS is located.

[0037] (MIMO technology advances and beams) Incidentally, although MIMO technology has been used in frequency bands (or frequency bands) lower than 6 GHz up to now, it is being considered that it will be applied to frequency bands higher than 6 GHz in the future.

[0038] Note that frequency bands lower than 7.125 GHz may be referred to as Frequency Range (FR) 1, etc. Frequency bands higher than 7.125 GHz / 24.250 GHz may be referred to as FR2, FR2-1, FR2-2, millimeter wave (mmW), FR4, etc.

[0039] The maximum number of MIMO layers is assumed to be limited by the antenna size.

[0040] Even at mmW, the use of high-order MIMO and cooperation among multiple UEs will improve the flexibility and diversity of MIMO multiplexing, and ultimately improve throughput.

[0041] In this way, it is expected that future wireless communication systems (e.g., NR from Rel-17 onwards) will use only digital beams (which may be called full digital operation) without analog beams, even at high frequencies (e.g., FR2), or will use operations that predominantly use digital beams.

[0042] For example, in the case of full digital operation, improvement in frequency utilization efficiency can be expected by simultaneously applying orthogonal precoding (or orthogonal beams, digital beams) to multiple UEs. If digital beams are not applied appropriately, interference between UEs increases, leading to deterioration of communication quality (or reduction in cell capacity). Note that orthogonal in this disclosure may be interpreted as quasi-orthogonal.

[0043] If a base station (which can also be read as a Transmission / Reception Point (TRP), panel, etc.) can only transmit one beam at a time, the base station switches the beam to transmit and receive to the UE. If a base station can transmit multiple beams at a time, the base station can simultaneously transmit and receive to and from multiple UEs using different beams.

[0044] Even if base stations become fully digital, as long as Rel.15 UE exists, Rel.15 UE should be accommodated (supported).

[0045] (DMRS) The front-loaded DMRS is the first DMRS (at or near the first symbol) for faster demodulation. The additional DMRS can be configured by RRC for fast-moving UEs or high modulation and coding scheme (MCS) / rank. The frequency location of the additional DMRS is the same as the front-loaded DMRS.

[0046] DMRS mapping type A or B is configured for the time domain. In DMRS mapping type A, DMRS position l_0 is counted by the symbol index within the slot. l_0 is configured by the parameter (dmrs-TypeA-Position) in the MIB or the common serving cell configuration (ServingCellConfigCommon). DMRS position 0 (reference point l) refers to the first symbol of the slot or each frequency hop. In DMRS mapping type B, DMRS position l_0 is counted by the symbol index within the PDSCH / PUSCH. l_0 is always 0. DMRS position 0 (reference point l) refers to the first symbol of the PDSCH / PUSCH or each frequency hop.

[0047] The DMRS location is defined by a table in the specification and depends on the duration of the PDSCH / PUSCH, while the location of the additional DMRS is fixed.

[0048] For the frequency domain, (PDSCH / PUSCH) DMRS configuration type 1 or 2 is configured. DMRS configuration type 1 has a comb structure and is applicable to both CP-OFDM (transport precoding disabled) and DFT-S-OFDM (transport precoding enabled). DMRS configuration type 2 is applicable only to CP-OFDM.

[0049] A single symbol DMRS or a double symbol DMRS is configured.

[0050] Single-symbol DMRS is normally used (it is mandatory in Rel. 15). In single-symbol DMRS, the number of additional DMRS (symbols) is {0, 1, 2, 3}. Single-symbol DMRS supports both frequency hopping enabled and disabled. If the maximum number (maxLength) in the uplink DMRS configuration (DMRS-UplinkConfig) is not set, single-symbol DMRS is used.

[0051] Double-symbol DMRS is used for more DMRS ports (especially MU-MIMO). In double-symbol DMRS, the number of additional DMRS (symbols) is {0, 1}. Double-symbol DMRS is supported when frequency hopping is disabled. If the maximum number (maxLength) in the uplink DMRS configuration (DMRS-UplinkConfig) is 2 (len2), whether it is single-symbol DMRS or double-symbol DMRS is determined by the DCI or configured grant.

[0052] From the above, the possible configuration patterns of DMRS are the following combinations: DMRS setting type 1, DMRS mapping type A, single symbol DMRS DMRS setting type 1, DMRS mapping type A, double symbol DMRS DMRS setting type 1, DMRS mapping type B, single symbol DMRS DMRS setting type 1, DMRS mapping type B, double symbol DMRS DMRS setting type 2, DMRS mapping type A, single symbol DMRS DMRS setting type 2, DMRS mapping type A, double symbol DMRS DMRS setting type 2, DMRS mapping type B, single symbol DMRS DMRS setting type 2, DMRS mapping type B, double symbol DMRS

[0053] Multiple DMRS ports that are mapped to the same time and frequency resource (RE) are called a DMRS code division multiplexing (CDM) group.

[0054] For DMRS configuration type 1 and single-symbol DMRS, four DMRS ports can be used. Within each DMRS CDM group, two DMRS ports are multiplexed using FDM OCC of length 2. Between multiple DMRS CDM groups (two DMRS CDM groups), two DMRS ports are multiplexed using FDM.

[0055] For DMRS configuration type 1 and double-symbol DMRS, eight DMRS ports can be used. Within each DMRS CDM group, two DMRS ports are multiplexed using an FD OCC of length 2, and two DMRS ports are multiplexed using a TD OCC. Between multiple DMRS CDM groups (two DMRS CDM groups), two DMRS ports are multiplexed using FDM.

[0056] Six DMRS ports can be used for DMRS configuration type 2 and single-symbol DMRS. Within each DMRS CDM group, two DMRS ports are multiplexed using FDM OCC of length 2. Between multiple DMRS CDM groups (three DMRS CDM groups), three DMRS ports are multiplexed using FDM.

[0057] For DMRS configuration type 2 and double-symbol DMRS, 12 DMRS ports can be used. Within each DMRS CDM group, two DMRS ports are multiplexed using an FD OCC of length 2, and two DMRS ports are multiplexed using a TD OCC. Between multiple DMRS CDM groups (three DMRS CDM groups), three DMRS ports are multiplexed using FDM.

[0058] Although an example of DMRS mapping type B is shown here, DMRS mapping type A is also similar.

[0059] In the parameters for PDSCH DMRS (existing table, existing DMRS port table, FIG. 1), DMRS ports 1000-1007 can be used for DMRS configuration type 1, and DMRS ports 1000-1011 can be used for DMRS configuration type 2.

[0060] In the parameters for PUSCH DMRS (existing table, existing DMRS port table, FIG. 2), DMRS ports 0-7 can be used for DMRS configuration type 1, and DMRS ports 0-11 can be used for DMRS configuration type 2.

[0061] (Reference signal port) For orthogonalization of MIMO layers, multi-port reference signals (for example, demodulation reference signals (DMRS) and CSI-RS) are used.

[0062] For example, for Single User MIMO (SU-MIMO), a different DMRS port / CSI-RS port may be configured for each layer. For Multi User MIMO (MU-MIMO), a different DMRS port / CSI-RS port may be configured for each layer within one UE and for each UE.

[0063] In addition, using a number of CSI-RS ports greater than the number of layers used for data is expected to enable more accurate measurement of channel conditions based on this CSI-RS, contributing to improved throughput.

[0064] In Rel.15 NR, multi-port DMRS is supported using Frequency Division Multiplexing (FDM), Frequency Domain Orthogonal Cover Code (FD-OCC), Time Domain OCC (TD-OCC), etc., with up to eight ports for Type 1 DMRS (i.e., DMRS configuration Type 1) and up to 12 ports for Type 2 DMRS (i.e., DMRS configuration Type 2).

[0065] In Rel.15 NR, a comb-like transmission frequency pattern (comb-like resource set) is used for the FDM. Cyclic Shift (CS) is used for the FD-OCC. Furthermore, TD-OCC can only be applied to double-symbol DMRS.

[0066] The OCC in the present disclosure may be interchangeably read as orthogonal code, orthogonalization, cyclic shift, and the like.

[0067] The type of DMRS may also be referred to as a DMRS configuration type.

[0068] Among DMRSs, a DMRS that is resource mapped in units of two consecutive (adjacent) symbols may be called a double-symbol DMRS, and a DMRS that is resource mapped in units of one symbol may be called a single-symbol DMRS.

[0069] Either DMRS may be mapped to one or more symbols per slot depending on the length of the data channel. A DMRS mapped to the beginning of a data symbol may be called a front-loaded DMRS, and a DMRS mapped to another position may be called an additional DMRS.

[0070] In the case of DMRS configuration type 1 and single-symbol DMRS, comb and CS may be used for orthogonalization. For example, up to four antenna ports (APs) may be supported by using two types of comb and two types of CS (Comb2+2CS).

[0071] In the case of DMRS configuration type 1 and double-symbol DMRS, comb, CS, and TD-OCC may be used for orthogonalization. For example, up to eight APs may be supported using two types of comb, two types of CS, and TD-OCC ({1,1} and {1,-1}).

[0072] In the case of DMRS configuration type 2 and single-symbol DMRS, FD-OCC may be used for orthogonalization. For example, up to six APs may be supported by applying an orthogonal code (2-FD-OCC) to two adjacent resource elements (REs) in the frequency direction.

[0073] In the case of DMRS configuration type 2 and double-symbol DMRS, FD-OCC and TD-OCC may be used for orthogonalization. For example, up to 12 APs may be supported by applying an orthogonal code (2-FD-OCC) to two adjacent REs in the frequency direction and applying TD-OCC ({1,1} and {1,-1}) to two adjacent REs in the time direction.

[0074] Furthermore, in Rel. 15 NR, up to 32 ports of the CSI-RS are supported by using FDM, time division multiplexing (TDM), frequency domain OCC, time domain OCC, etc. The same method as for the DMRS described above may also be applied to orthogonalizing the CSI-RS.

[0075] Now, a group of DMRS ports that are orthogonalized by FD-OCC / TD-OCC as described above is also called a Code Division Multiplexing (CDM) group.

[0076] Different CDM groups are orthogonal because they are FDM-modulated. However, within the same CDM group, the orthogonality of the applied OCC may be lost due to channel fluctuations, etc. In this case, if signals within the same CDM group are received with different received power levels, a near-far problem may occur, and orthogonality may not be guaranteed.

[0077] Here, we will explain TD-OCC / FD-OCC of DMRS in Rel.15 NR. DMRS mapped to resource elements (RE) is a DMRS sequence with FD-OCC parameters (which may also be called sequence elements). f (k') and the TD-OCC parameter (which may also be called a sequence element) w t It may correspond to a series obtained by multiplying (l') and

[0078] Both the TD-OCC and FD-OCC of Rel.15 NR DMRS correspond to OCCs with a sequence length (which may also be called the OCC length) of 2. Therefore, the possible values ​​of k' and l' above are both 0 and 1. By multiplying this FD-OCC in RE units, two-port DMRSs can be multiplexed using the same time and frequency resources (2RE). By applying both the FD-OCC and TD-OCC, four-port DMRSs can be multiplexed using the same time and frequency resources (4RE).

[0079] The two existing DMRS port tables for PDSCH described above (association of antenna port indexes (numbers) with parameters) correspond to DMRS configuration type 1 and type 2, respectively. Note that p indicates the antenna port number, and Δ indicates a parameter for shifting (offsetting) the frequency resource.

[0080] For example, for antenna ports 1000 and 1001, f (0), w f (1)}={+1,+1} and {w f (0), w f (1)}={+1,-1} is applied to the orthogonalized vectors using FD-OCC.

[0081] FDM is applied to antenna ports 1000-1001 and antenna ports 1002-1003 (and also antenna ports 1004-1005 in the case of Type 2) by applying different values ​​of Δ to them. Therefore, antenna ports 1000-1003 (or 1000-1005) corresponding to single-symbol DMRS are orthogonalized using FD-OCC and FDM.

[0082] For the antenna ports 1000-1003 and the antenna ports 1004-1007 of Type 1, t (0), w t (1)}={+1,+1} and {w t (0), w t Therefore, the antenna ports 1000-1007 (or 1000-1011) corresponding to the double-symbol DMRS are orthogonalized using FD-OCC, TD-OCC, and FDM.

[0083] For CP-OFDM only, the following are considered: specifying a larger number of orthogonal DMRS ports for DL / UL MU-MIMO (without increasing DMRS overhead); common design between DL and UL DMRS; up to 24 orthogonal DMRS ports; doubling the maximum number of orthogonal DMRS ports for both single-symbol DMRS and double-symbol DMRS for each applicable DMRS configuration type.

[0084] In Rel. 15, the following cases 1 to 4 can be set. [Case 1] Single-symbol DMRS with DMRS setting type 1 The total number of DMRS ports is 2 (by comb / FDM)×2 (by FD OCC)=4 ports. [Case 2] Double symbol DMRS with DMRS setting type 1 The total number of DMRS ports is 2 (by comb / FDM) x 2 (by FD OCC) x 2 (by TD OCC) = 8 ports. [Case 3] Single-symbol DMRS with DMRS setting type 2 The total number of DMRS ports is 3 (by FDM) × 2 (by FD OCC) = 6 ports. [Case 4] Double symbol DMRS with DMRS setting type 2 The total number of DMRS ports is 3 (by comb) × 2 (by FD OCC) × 2 (by TD OCC) = 12 ports.

[0085] In Rel. 18, it is considered to double the total number of DMRS ports to 8, 16, 12, and 24 for cases 1, 2, 3, and 4, respectively.

[0086] To increase the number of DMRS ports, the following five options (methods for increasing the number of DMRS ports) are being considered.

[0087] <Option 1> · Introduction of new OCCs with lengths greater than existing OCCs (e.g., 4 or 6). In Option 1, the issues to be considered include the possibility of performance degradation when the delay spread is large, the possibility of scheduling restrictions, and backward compatibility.

[0088] <Option 2> Use of TD-OCC on non-contiguous multiple DMRS symbols (e.g., TD-OCC on front-loaded / additional DMRS). In Option 2, considerations include the possibility of performance degradation at high UE speeds, possible scheduling restrictions (e.g., how frequency hopping is applied), possible restrictions on DMRS configuration (e.g., limiting the number of additional DMRSs), and backward compatibility.

[0089] <Option 3> Increase the number of CDM groups (e.g. increase the number of combs / FDMs). In Option 3, issues to be considered include the possibility of performance degradation when the delay spread is large, and backward compatibility.

[0090] <Option 4> Reuse symbols for additional DMRS to increase orthogonal DMRS ports. In option 4, the possible degradation of performance when the UE speed is high, the possible limitation of DMRS configuration (e.g., the number of additional DMRSs is limited), and backward compatibility are some of the issues to be considered.

[0091] <Option 5> Use of TD-OCC on multiple non-contiguous DMRS symbols in combination with FD-OCC / FDM (reuse symbols of additional DMRS to improve channel estimation performance). In Option 5, considerations include the possibility of performance degradation at high UE speeds, possible scheduling restrictions (e.g., how frequency hopping is applied), possible restrictions on DMRS configuration (e.g., limiting the number of additional DMRSs), and backward compatibility.

[0092] In option 1, the new FD-OCC for DMRS of PDSCH / PUSCH may follow at least one of the following options for new DMRS configuration type 1. <<Option 1-1>> A new FD-OCC of length 6 is applied to 6REs of DMRS in one PRB in one CDM group. <<Option 1-2>> Within one CDM group, a new FD-OCC of length 4 is applied to 4REs of DMRS within one PRB or across multiple consecutive PRBs.

[0093] In Option 1, for the new FD-OCC for the DMRS of PDSCH / PUSCH, a new FD-OCC of length 4 is applied to 4 REs of the DMRS in one PRB in one CDM group for new DMRS configuration type 2. A new FD-OCC of length 6 may also be supported for new DMRS configuration type 2.

[0094] In the present disclosure, existing FD-OCC#0=[+1 +1] and existing FD-OCC#1=[+1 −1] may also be used.

[0095] The novel FD-OCC may be any of several OCCs:

[0096] [OCC-a] OCC of length 4 based on a 4x4 Walsh matrix (sequence). As shown in the example in Figure 3A, four sequences are obtained for OCC index i={0,1,2,3}.

[0097] [OCC-b] Length-4 OCC based on cyclic shifts. As shown in the example in Figure 3B, for OCC index i = {0, 1, 2, 3}, four sequences are obtained by using cyclic shifts {i·0, i·π / 2, i·π, i·3π / 2}.

[0098] [OCC-c] As in the example in Figure 3C, in OCC-b, the OCCs with OCC indices 1 and 2 are exchanged.

[0099] [OCC-d] FFT (DFT) based OCC of length 6. As shown in the example in Figure 3D, for OCC index i = {0, 1, 2, 3, 4, 5}, six sequences are obtained from each row of the DFT matrix.

[0100] [OCC-e] Like OCC-a and OCC-c, OCCs of length 4 consist of a repetition of an OCC of length 2 (existing FD-OCC). As shown in the example of Figure 4, the first and second halves of length 4 OCCs #0 and #1 (OCCs corresponding to OCC indexes 0 and 1) are the same as length 2 OCCs #0 and #1 (OCCs corresponding to OCC indexes 0 and 1).

[0101] In the present disclosure, the OCC (FD-OCC / TD-OCC) corresponding to OCC index i may be referred to as OCC#i.

[0102] Some of the multiple sequences of the new FD-OCC may be associated with existing DMRS port indexes.

[0103] When FD-OCC of length 2 is used, an existing DMRS port table may be used. The existing DMRS port table for DMRS configuration type 1 may be the DMRS port table of FIG. 5 or the DMRS port table of DMRS configuration type 1 of FIG.

[0104] If the new FD-OCC is OCC-e, the new DMRS port table for DMRS configuration type 1 may be the DMRS port table in FIG. 6. The new DMRS port table may indicate the DMRS ports (p is 0 or greater) corresponding to the new FD-OCC. At least some of the values ​​of p in the new DMRS port table may overlap with the values ​​of p in the existing DMRS port table. If use of a new FD-OCC is configured / instructed, the UE may use the new DMRS port table, and if use of a new FD-OCC is not configured / instructed, the UE may use the existing DMRS port table. As in this example, the same DMRS port index (0 to 7 for existing DMRS ports, DMRS configuration type 1) as the existing DMRS ports may be used for DMRS ports with new FD-OCCs #0 and #1. A different DMRS port index (8 to 15 for new DMRS ports, DMRS configuration type 1) from the existing DMRS ports may be used for DMRS ports with new FD-OCCs #2 and #3.

[0105] Some of the multiple sequences of the new FD-OCC may not be associated with existing DMRS port indexes.

[0106] As in the example of Figure 7, the new DMRS port table may indicate only the DMRS ports corresponding to the new FD-OCC. The DMRS port indexes corresponding to the new FD-OCC may not overlap with the DMRS port indexes corresponding to the existing FD-OCC.

[0107] 8, a new DMRS port table may include a DMRS port corresponding to an existing FD-OCC and a DMRS port corresponding to a new FD-OCC, and in the new DMRS port table, the DMRS port index corresponding to the new FD-OCC may be added after the DMRS port index corresponding to the existing FD-OCC.

[0108] If the new FD-OCC is OCC-e, the new DMRS port table for DMRS configuration type 2 may be the DMRS port table in FIG. 9 or may follow the same rules as those in FIGS.

[0109] (MU-MIMO scheduling constraints) For MU-MIMO, multiple DMRSs are multiplexed for multiple UEs. The multiple DMRSs may be CDM-multiplexed using different OCCs within a single CDM group, or FDM-multiplexed using different subcarriers (combs) across multiple CDM groups. CDM can cause problems due to differences in the distances from the base station to the multiple UEs (near-far problem). While inter-symbol interference does not occur in a flat fading environment, it does occur in a frequency-selective fading environment, resulting in reduced quality. To prevent this, MU-MIMO scheduling constraints (existing MU-MIMO scheduling constraints) have been defined.

[0110] For PDSCH using DMRS configuration type 1, the following MU-MIMO scheduling constraints are specified: In DMRS configuration type 1, if a UE is scheduled with one codeword (CW) and is assigned an antenna port mapping with indices {2, 9, 10, 11, 30} in the existing antenna port table for DMRS configuration type 1, or if a UE is scheduled with two CWs, the UE may assume that the remaining orthogonal antenna ports are not associated with transmitting PDSCH to another UE.

[0111] When the number of DMRS CDM groups without data and rank 1 (one DMRS port) are specified, there may be no restrictions within the same CDM group (one DMRS port of another UE may be CDMed to the DMRS port of the UE). When the number of DMRS CDM groups without data and rank 2 (two DMRS ports) are specified, all DMRS ports within the same CDM group are specified, so the DMRS port of the UE cannot be CDMed to the DMRS port of another UE within the same CDM group. When the number of DMRS CDM groups without data and rank 3 (three DMRS ports) are specified, three DMRS ports out of four DMRS ports within two CDM groups are specified, so one DMRS port is free, but one DMRS port of another UE cannot be CDMed to it. For the case where the number of DMRS CDM groups without data is 2 and rank is 4 (4 DMRS ports), all DMRS ports within the same CDM group are indicated, so that the DMRS port of the UE cannot be CDMed with the DMRS port of another UE within the same CDM group.

[0112] However, it is not clear how to specify antenna ports (DMRS ports) when a new FD-OCC longer than 2 is used. If such behavior is not clear, communication throughput / communication quality may be degraded.

[0113] Therefore, the present inventors came up with the idea of ​​antenna port instruction operation.

[0114] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the following embodiments (for example, each case) may be used alone, or at least two of them may be combined and applied.

[0115] In the present disclosure, "A / B" and "at least one of A and B" may be interpreted interchangeably. Also, in the present disclosure, "A / B / C" may mean "at least one of A, B, and C."

[0116] In the present disclosure, terms such as activate, deactivate, indicate (or indicate), select, configure, update, and determine may be read interchangeably. In the present disclosure, terms such as support, control, controllable, operate, and operate may be read interchangeably.

[0117] In the present disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, information elements (IEs), configurations, etc. may be interchangeable. In the present disclosure, Medium Access Control (MAC) control elements (CEs), update commands, activation / deactivation commands, etc. may be interchangeable.

[0118] In the present disclosure, higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, and the like, or a combination thereof.

[0119] In the present disclosure, MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. Broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0120] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0121] In this disclosure, the terms index, identifier (ID), indicator, resource ID, etc. may be interchangeable. In this disclosure, the terms sequence, list, set, group, cluster, subset, etc. may be interchangeable.

[0122] In this disclosure, the terms panel, panel group, beam, beam group, precoder, uplink (UL) transmitting entity, transmission / reception point (TRP), base station, spatial relation information (SRI), spatial relation, SRS resource indicator (SRI), control resource set (CORESET), physical downlink shared channel (PDSCH), codeword (CW), transport block (TB), reference signal (RS), antenna port (e.g., demodulation reference signal (DMRS) port), antenna port group (e.g., DMRS port group), group (e.g., spatial relation group, code division multiplexing (CDM) group, reference signal group, CORESET group, physical uplink control Channel (PUCCH) group, PUCCH resource group), resource (e.g., reference signal resource, SRS resource), resource set (e.g., reference signal resource set), CORESET pool, downlink Transmission Configuration Indication state (TCI state) (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, Quasi-Co-Location (QCL), QCL assumption, etc. may be read as interchangeable.

[0123] In this disclosure, "having the capability of..." may be read interchangeably as "supporting / reporting the capability of...".

[0124] In the present disclosure, the terms DMRS port, antenna port, port, port number, and port index may be interchangeable.

[0125] In the present disclosure, RB and PRB may be read interchangeably.

[0126] In the present disclosure, OCC#i and the OCC corresponding to OCC index i may be read as interchangeable.

[0127] In each embodiment, the terms "DMRS port table" and "association of DMRS ports and parameters" may be interchangeable, and the parameters may include at least one of a CDM group, a Δ, an FD OCC, and a TD OCC.

[0128] In each embodiment, the antenna port indication table, the antenna port table, and the association of the antenna port field value and parameters may be interchangeable, and the parameters may include at least one of the number of DMRS CDM groups without data, the DMRS port (number / index), and the number of preceding DMRS symbols.

[0129] (Wireless communication method) In each embodiment, the existing FD-OCC, the FD-OCC with length 2, and w f (k') may be read interchangeably. In each embodiment, the novel FD-OCC, the FD-OCC longer than 2, w f (k') may be read interchangeably.

[0130] In each embodiment, DMRS port index i and DMRS port #i may be interchangeable. In each embodiment, the DMRS ports corresponding to new FD-OCCs #0, #1, #2, and #3 may be DMRS ports #i+0, #i+1, #i+2, and #i+3, or DMRS ports #i+0, #i+1, #j+0, and #j+1, or DMRS ports #i+0, #i+1, #i+M+0, and #i+M+1. i, j, and M may be multiples of 2, multiples of 4, or integers greater than or equal to 0. In each embodiment, an association between FD / TD-OCC indexes and DMRS port indexes, such as that in the existing / new DMRS port table described above, may be used. For example, if new DMRS ports (DMRS ports corresponding to new FD-OCCs #2 and #3) are indexed after existing DMRS ports (DMRS ports corresponding to new FD-OCCs #0 and #1) as in the new DMRS port table of Figure 6, M may be 8 for DMRS configuration type 1 and M may be 12 for DMRS configuration type 2. For example, for DMRS configuration type 1 of single-symbol DMRS, new FD-OCCs #0, #1, #2, and #3 in CDM group #0 may correspond to DMRS ports #0, #1, #8, and #9, respectively. For example, for DMRS configuration type 2 of single-symbol DMRS, new FD-OCCs #0, #1, #2, and #3 in CDM group #0 may correspond to DMRS ports #0, #1, #12, and #13, respectively.

[0131] The following embodiments may be applied to a DMRS of a PDSCH or a DMRS of a PUSCH, where the PUSCH DMRS port index may be represented as p, and the PDSCH DMRS port index may be represented as p+1000.

[0132] The following embodiments may be applied to either a single-symbol DMRS or a double-symbol DMRS, and may be applied to either a DMRS configuration type 1 or a DMRS configuration type 2.

[0133] <Embodiment 1> When a new DMRS is configured, at least one bit may be added to DCI format 0_1 / 0_2 / 1_1 / 1_2 to indicate the new DMRS port. In the present disclosure, the phrases "a new DMRS is configured" and "information such as a DMRS port / DMRS configuration type configured / indicated by time domain resource assignment / allocation (TDRA) or the like is associated with the new DMRS port" may be interpreted as interchangeable.

[0134] The extension of the antenna port field / antenna port table may follow at least one of several options below.

[0135] -Option 1 A new antenna port table based on the existing antenna port table is defined. The number of entries in the new antenna port table may be greater than the number of entries in the existing antenna port table. The size of the antenna port field may be increased from 4, 5, or 6 bits to 5, 6, or 7 bits, respectively. The new antenna port table may associate a certain antenna port field value with both an existing DMRS port and a new DMRS port. This option allows for flexible association of antenna port field values ​​with DMRS ports.

[0136] The new antenna port table may be obtained by adding entries for new DMRS ports to the entries for all existing DMRS ports in the existing antenna port table. Figure 10 shows an example of a new antenna port table for single symbol DMRS and DMRS configuration type 1. As in this example, the new antenna port table may include entries corresponding to existing DMRS ports #1000 to #1011 and entries corresponding to existing DMRS ports #1012 to #1023.

[0137] The size of the antenna port field referencing the new antenna port table may be Y bits larger than the size of the antenna port field referencing the existing antenna port table. Y may be 1. Both the existing antenna port table and the new antenna port table may be defined in the specification. The existing antenna port table may be replaced by the new antenna port table. The new antenna port table may include only entries for new DMRS ports. The size of the antenna port field referencing the new antenna port table may be the same as the size of the antenna port field referencing the existing antenna port table. Whether the antenna port field refers to the existing antenna port table or the new antenna port table may be configured by higher layer signaling or defined in the specification.

[0138] When a new DMRS is configured, the size of the antenna port field in DCI format 0_1 / 0_2 / 1_1 / 1_2 may or may not necessarily increase by Y bits.

[0139] Y may be equal to or greater than 2. For example, if dynamic switching (switching based on DCI) between an existing FD-OCC and a new FD-OCC is supported / configured, the antenna port field may indicate whether the FD-OCC length is 2 or longer than 2 (whether the FD-OCC is an existing FD-OCC or a new FD-OCC). In this case, Y may be 2 bits.

[0140] -Option 2 The existing antenna port table is reused. This option can reduce the complexity / load on the UE. Figure 11 shows an example of the existing antenna port table for single symbol DMRS and DMRS configuration type 1.

[0141] The size of the antenna port field in the DCI may remain unchanged. A new DCI field may be introduced to indicate a new DMRS port. The size of the new DCI field may be 1 bit. The new DCI field may be referred to as a DMRS port offset indicator field. Figure 12 shows an example of the relationship between the value of the new DCI field and the DMRS port offset. As in this example, the values ​​0 and 1 of the 1 bit of the new DCI field may be associated with DMRS port offsets 0 and X, respectively. The UE may use a DMRS port having an index that is the sum of the DMRS port index and the DMRS port offset indicated by the antenna port field in DCI format 0_1 / 0_2 / 1_1 / 1_2 for transmitting and receiving DMRS.

[0142] If the DMRS Port Offset Indicator field is set to "0", the DMRS port may be the same as the DMRS port indicated by the Antenna Port field in DCI format 0_1 / 0_2 / 1_1 / 1_2. If the DMRS Port Offset Indicator field is set to "1", the DMRS port actually used may be the DMRS port index indicated by the Antenna Port field in DCI format 0_1 / 0_2 / 1_1 / 1_2 plus X. The value of X is 8 for DMRS configuration type 1 and 12 for DMRS configuration type 2.

[0143] When a new DMRS is configured, a new DCI field may or may not necessarily be added to DCI format 0_1 / 0_2 / 1_1 / 1_2. If a new DCI field is not added / configured (no new DCI field exists), the value of X may be configured / indicated by the RRC IE / MAC CE. This can reduce DCI overhead and prevent a reduction in PDCCH coverage.

[0144] A group of DMRS ports to which a DMRS port offset is not applied and a group of DMRS ports to which a DMRS port offset is applied may be defined. In the present disclosure, the terms group, subset, and group subset may be interchangeable. The new DCI field may indicate an index of the group.

[0145] The size of the new DCI field may be 2 bits or more. For example, if dynamic switching (DCI-based switching) between an existing FD-OCC and a new FD-OCC is supported / configured, the new DCI field may indicate whether the FD-OCC length is 2 or longer than 2 (whether the FD-OCC is an existing FD-OCC or a new FD-OCC). In this case, the size of the new DCI field may be 2 bits.

[0146] -Variations In the existing specifications, the remaining DMRS ports (unspecified DMRS ports among the DMRS ports in the CDM group) for ranks greater than four (two codewords) are not allocated to other UEs.

[0147] In Options 1 / 2, according to the limitations of the existing specifications, existing DMRS ports (e.g., DMRS ports 0 to 7 in DMRS Configuration Type 1) and new DMRS ports (e.g., DMRS ports 8 to 15 in DMRS Configuration Type 1) cannot be assigned simultaneously. For example, DMRS ports #0, #1, #8, and #9 corresponding to one CDM group cannot be assigned to one UE. According to the limitations of the existing specifications, a maximum of two DMRS ports can be assigned within each CDM group, and the remaining DMRS ports are wasted (cannot be used). In other words, single-symbol DMRS and ranks greater than four are not supported.

[0148] Therefore, the new antenna port table may support single symbol DMRS and indication of ranks (DMRS ports) greater than 4, thereby reducing DMRS overhead.

[0149] One value in the antenna port field may be associated with both at least one existing DMRS port and at least one new DMRS port. In other words, one entry in the antenna port table may indicate a combination of both at least one existing DMRS port and at least one new DMRS port. For example, one entry in the antenna port table for DMRS configuration type 1 may indicate a combination of at least one of DMRS ports #0 to #7 and at least one of DMRS ports #8 to #15. For example, one entry in the antenna port table for DMRS configuration type 2 may indicate a combination of at least one of DMRS ports #0 to #11 and at least one of DMRS ports #12 to #23.

[0150] In Option 1 / 2, one value of the reserved bit in the antenna port table may be associated with both at least one existing DMRS port and at least one new DMRS port. This antenna port table may be the new antenna port table in Option 1 or the existing antenna port table in Option 2. For example, at least one value (maximum of eight values) of antenna port field values ​​24-31 in FIG. 10 may indicate a combination of at least one existing DMRS port and at least one new DMRS port. For example, values ​​(maximum of eight entries) corresponding to the combination of antenna port field values ​​12-15 in FIG. 11 and new DCI field value {0,1} in FIG. 12 may indicate a combination of at least one existing DMRS port and at least one new DMRS port.

[0151] According to this embodiment, the UE can be appropriately instructed to use new antenna ports, thereby enabling the UE to utilize more DMRS ports than the existing specifications.

[0152] <Supplementary information> [Notifying information to UE] In the above-described embodiments, notification of any information (from a network (NW) (e.g., a base station (BS))) to a UE (in other words, reception of any information from a BS at the UE) may be performed using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PDCCH, PDSCH, reference signal), or a combination thereof.

[0153] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new Logical Channel ID (LCID) in the MAC subheader, which is not defined in existing standards.

[0154] When the notification is made by DCI, the notification may be made by a specific field of the DCI, a Radio Network Temporary Identifier (RNTI) used to scramble the Cyclic Redundancy Check (CRC) bits assigned to the DCI, the format of the DCI, etc.

[0155] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0156] [Information notification from UE] In the above-described embodiments, notification of any information from the UE (to the NW) (in other words, transmission / reporting of any information from the UE to the BS) may be performed using physical layer signaling (e.g., UCI), higher layer signaling (e.g., RRC signaling, MAC CE), specific signals / channels (e.g., PUCCH, PUSCH, PRACH, reference signals), or a combination thereof.

[0157] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new LCID, which is not defined in existing standards, in the MAC subheader.

[0158] If the notification is performed by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0159] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0160] [Application of each embodiment] At least one of the above-described embodiments may be applied when a specific condition is met, which may be specified in a standard or may be notified to a UE / BS using higher layer signaling / physical layer signaling.

[0161] At least one of the above embodiments may be applied only to UEs that have reported or support a particular UE capability.

[0162] The specific UE capabilities may indicate at least one of the following: Supporting specific processing / operations / control / information for at least one of the above embodiments. Supports a greater number of DMRS ports for PDSCH / PUSCH than in existing specifications. Supports a greater number of DMRS ports than existing specifications using TD-OCC / FD-OCC / FDM for PDSCH / PUSCH DMRS. Supports FD OCC of length 4 / 6. Support new antenna port table. Support for new DCI fields.

[0163] Furthermore, the above-mentioned specific UE capability may be a capability that is applied across all frequencies (commonly regardless of frequency), or may be a capability for each frequency (e.g., one or a combination of a cell, band, band combination, BWP, component carrier, etc.), or may be a capability for each frequency range (e.g., Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), or may be a capability for each subcarrier spacing (SubCarrier Spacing (SCS)), or may be a capability for each Feature Set (FS) or Feature Set Per Component-carrier (FSPC).

[0164] Furthermore, the specific UE capability may be a capability that is applied across all duplexing methods (commonly regardless of the duplexing method), or may be a capability for each duplexing method (for example, Time Division Duplex (TDD) or Frequency Division Duplex (FDD)).

[0165] Furthermore, at least one of the above-described embodiments may be applied when specific information related to the above-described embodiments (or performing the operations of the above-described embodiments) is configured / activated / triggered in the UE by higher layer signaling / physical layer signaling. For example, the specific information may be information indicating that the functions of the respective embodiments are enabled, any RRC parameters for a specific release (e.g., Rel. 18 / 19), etc.

[0166] If the UE does not support at least one of the specific UE capabilities or is not configured with the specific information, the UE may apply, for example, Rel. 15 / 16 behavior.

[0167] (Addendum) The following inventions are added regarding one embodiment of the present disclosure. [Appendix 1] a receiver for receiving downlink control information (DCI) indicating a port of a second DMRS among a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied; a control unit that controls reception or transmission of the second DMRS, A terminal, wherein the size of the second information for indicating the port of the second DMRS is larger than the size of the first information for indicating the port of the one DMRS. [Appendix 2] The terminal described in Supplementary Note 1, wherein the second information is an antenna port field. [Appendix 3] the second information includes an antenna port field and a field indicating an offset to be added to a value indicated by the antenna port field; The terminal according to Supplementary Note 1 or 2, wherein the control unit determines the port of the second DMRS by a sum of the value and the offset. [Appendix 4] 4. The terminal according to any one of Supplementary Note 1 to Supplementary Note 3, wherein one value of the second information is associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

[0168] (wireless communication system) The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

[0169] 13 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 (which may be simply referred to as system 1) may be a system that realizes communication using Long Term Evolution (LTE), 5th generation mobile communication system New Radio (5G NR), or the like, which are specified by the Third Generation Partnership Project (3GPP).

[0170] The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0171] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (MN), and the NR base station (gNB) is the secondary node (SN). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0172] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity in which both the MN and the SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

[0173] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form small cells C2 that are smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The locations and numbers of the cells and user terminals 20 are not limited to the embodiment shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as base station 10.

[0174] The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CC) and dual connectivity (DC).

[0175] Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). The macro cell C1 may be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band above 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may be a frequency band higher than FR2.

[0176] Furthermore, the user terminal 20 may perform communication using at least one of Time Division Duplex (TDD) and Frequency Division Duplex (FDD) in each CC.

[0177] The multiple base stations 10 may be connected by wire (for example, optical fiber conforming to the Common Public Radio Interface (CPRI), an X2 interface, or the like) or wirelessly (for example, NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11 corresponding to the upper station may be called an Integrated Access Backhaul (IAB) donor, and the base station 12 corresponding to the relay station (relay) may be called an IAB node.

[0178] The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

[0179] The core network 30 may include network functions (NFs) such as a User Plane Function (UPF), an Access and Mobility management Function (AMF), a Session Management Function (SMF), a Unified Data Management (UDM), an Application Function (AF), a Data Network (DN), a Location Management Function (LMF), and an Operation, Administration and Maintenance (Management) (OAM). Note that a single network node may provide multiple functions. Furthermore, communication with an external network (e.g., the Internet) may be performed via the DN.

[0180] The user terminal 20 may be a terminal compatible with at least one of communication methods such as LTE, LTE-A, and 5G.

[0181] An Orthogonal Frequency Division Multiplexing (OFDM)-based radio access scheme may be used in the radio communication system 1. For example, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), or the like may be used in at least one of the downlink (DL) and the uplink (UL).

[0182] The radio access scheme may also be called a waveform. Note that in the wireless communication system 1, other radio access schemes (for example, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0183] In the wireless communication system 1, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20, a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. may be used as the downlink channel.

[0184] Furthermore, in the wireless communication system 1, an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc. may be used as an uplink channel.

[0185] The PDSCH transmits user data, higher layer control information, System Information Block (SIB), etc. The PUSCH may transmit user data, higher layer control information, etc. Furthermore, the PBCH may transmit Master Information Block (MIB).

[0186] Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

[0187] Note that the DCI for scheduling the PDSCH may be referred to as a DL assignment, a DL DCI, etc., and the DCI for scheduling the PUSCH may be referred to as an UL grant, a UL DCI, etc. Note that the PDSCH may be interpreted as DL data, and the PUSCH may be interpreted as UL data.

[0188] A control resource set (CORESET) and a search space may be used to detect the PDCCH. The CORESET corresponds to resources to search for DCI. The search space corresponds to a search region and a search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor a CORESET associated with a certain search space based on the search space configuration.

[0189] One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be called a search space set. Note that the terms "search space," "search space set," "search space setting," "search space set setting," "CORESET," "CORESET setting," etc. in the present disclosure may be read interchangeably.

[0190] The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), acknowledgement information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

[0191] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

[0192] In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted as DL-RS.

[0193] The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including the SS (PSS, SSS) and the PBCH (and DMRS for the PBCH) may be referred to as an SS / PBCH block, an SS Block (SSB), or the like. Note that the SS, SSB, and the like may also be referred to as reference signals.

[0194] Furthermore, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), etc. may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may also be called a user equipment-specific reference signal (UE-specific reference signal).

[0195] (base station) 14 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

[0196] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the base station 10 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0197] The control unit 110 performs overall control of the base station 10. The control unit 110 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0198] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data to be transmitted as signals, control information, sequences, etc., and transfer them to the transceiver unit 120. The control unit 110 may perform call processing (setting up, releasing, etc.) of communication channels, status management of the base station 10, management of radio resources, etc.

[0199] The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0200] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 1211 and an RF unit 122. The receiving unit may be composed of a reception processing unit 1212, an RF unit 122, and a measurement unit 123.

[0201] The transmitting and receiving antenna 130 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure pertains, such as an array antenna.

[0202] The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

[0203] The transceiver 120 may form at least one of a transmission beam and a reception beam using digital beamforming (for example, precoding), analog beamforming (for example, phase rotation), or the like.

[0204] The transceiver 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0205] The transceiver 120 (transmission processor 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0206] The transmitting / receiving unit 120 (RF unit 122) may perform modulation to a radio frequency band, filtering, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmitting / receiving antenna .

[0207] On the other hand, the transmitting / receiving unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transmitting / receiving antenna .

[0208] The transceiver 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

[0209] The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

[0210] The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30 (e.g., network nodes providing NFs), other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0211] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0212] The transceiver 120 may transmit downlink control information (DCI) indicating a port for a second demodulation reference signal (DMRS) of a first DMRS to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied. The controller 110 may control reception or transmission of the second DMRS. The size of the second information for indicating the port for the second DMRS may be larger than the size of the first information for indicating the port for the one DMRS.

[0213] (user terminal) 15 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the user terminal 20 may include one or more of each of the control unit 210, the transceiver unit 220, and the transceiver antenna 230.

[0214] Note that this example mainly shows functional blocks of the characteristic parts of the present embodiment, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0215] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0216] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may also control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transceiver unit 220.

[0217] The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured from a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0218] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiving unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

[0219] The transmitting / receiving antenna 230 can be configured as an antenna described based on common understanding in the technical field to which the present disclosure pertains, such as an array antenna.

[0220] The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0221] The transceiver 220 may form at least one of a transmission beam and a reception beam using digital beamforming (for example, precoding), analog beamforming (for example, phase rotation), or the like.

[0222] The transceiver 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0223] The transceiver 220 (transmission processor 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0224] Whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform, and when transform precoding is not enabled, the transceiver unit 220 may not perform DFT processing as the transmission processing.

[0225] The transmitting / receiving unit 220 (RF unit 222) may perform modulation to a radio frequency band, filtering, amplification, etc. on the baseband signal, and transmit the radio frequency band signal via the transmitting / receiving antenna 230.

[0226] On the other hand, the transmitting / receiving unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transmitting / receiving antenna 230.

[0227] The transceiver 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal to acquire user data, etc.

[0228] The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurement, CSI measurement, etc. based on the received signal. The measurement unit 223 may measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 210.

[0229] The transmitting section and receiving section of the user terminal 20 in the present disclosure may be configured by at least one of the transmitting / receiving section 220 and the transmitting / receiving antenna 230.

[0230] The transceiver 220 may receive downlink control information (DCI) indicating a port for a second demodulation reference signal (DMRS) of a first DMRS to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied. The controller 210 may control reception or transmission of the second DMRS. The size of the second information for indicating the port for the second DMRS may be larger than the size of the first information for indicating the port for the one DMRS.

[0231] The second information may be an antenna port field.

[0232] The second information may include an antenna port field and a field indicating an offset to be added to the value indicated by the antenna port field, and the controller 210 may determine the port of the second DMRS by adding the value and the offset.

[0233] One value of the second information may be associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

[0234] (Hardware configuration) The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may also be realized by combining the single device or multiple devices with software.

[0235] Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission may be called a transmitting unit, transmitter, etc. As mentioned above, the implementation method of each is not particularly limited.

[0236] For example, a base station, a user terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 16 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. The above-described base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0237] In this disclosure, terms such as apparatus, circuit, device, section, unit, etc. may be read interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0238] For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, serially, or in other ways. Furthermore, processor 1001 may be implemented by one or more chips.

[0239] Each function in the base station 10 and the user terminal 20 is realized, for example, by loading predetermined software (programs) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0240] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), transmission / reception unit 120 (220), etc. may be realized by the processor 1001.

[0241] The processor 1001 also reads programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 110 (210) may be realized by a control program stored in the memory 1002 and running on the processor 1001, and the other functional blocks may be realized in a similar manner.

[0242] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, a cache, a main memory, or the like. The memory 1002 may store executable programs (program codes), software modules, and the like for implementing a wireless communication method according to an embodiment of the present disclosure.

[0243] Storage 1003 is a computer-readable recording medium and may be constituted by at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disc (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, stick, key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as a secondary storage device.

[0244] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmission / reception unit 120 (220), transmission / reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission / reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

[0245] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (for example, a display, a speaker, a light emitting diode (LED) lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0246] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0247] Furthermore, the base station 10 and the user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized using such hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0248] (Variation) Note that terms explained in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

[0249] A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0250] Here, the numerology may be a communication parameter applied to at least one of transmission and reception of a signal or channel, and may indicate at least one of, for example, a subcarrier spacing (SCS), a bandwidth, a symbol length, a cyclic prefix length, a transmission time interval (TTI), the number of symbols per TTI, a radio frame structure, a specific filtering process performed by a transceiver in the frequency domain, and a specific windowing process performed by a transceiver in the time domain.

[0251] A slot may be composed of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol), and may be a time unit based on numerology.

[0252] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

[0253] A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting signals. The radio frame, the subframe, the slot, the minislot, and the symbol may be referred to by other names corresponding to the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in the present disclosure may be interchangeable.

[0254] For example, one subframe may be referred to as a TTI, or multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0255] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. However, the definition of TTI is not limited to this.

[0256] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0257] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0258] A TTI having a time length of 1 ms may be called a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0259] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0260] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may also be determined based on numerology.

[0261] In addition, an RB may include one or more symbols in the time domain and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0262] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0263] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0264] A Bandwidth Part (BWP), which may also be referred to as a fractional bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0265] The BWP may include an UL BWP (a BWP for UL) and a DL BWP (a BWP for DL). One or more BWPs may be configured for a UE within one carrier.

[0266] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0267] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0268] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

[0269] The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical expressions and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0270] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0271] Furthermore, information, signals, etc. may be output from a higher layer to a lower layer and / or from a lower layer to a higher layer. Information, signals, etc. may be input / output via multiple network nodes.

[0272] Input and output information, signals, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

[0273] Notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0274] Note that the physical layer signaling may be called Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. Furthermore, the RRC signaling may be called an RRC message, such as an RRC connection setup message or an RRC connection reconfiguration message. Furthermore, the MAC signaling may be notified using, for example, a MAC Control Element (CE).

[0275] Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

[0276] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value represented by true or false, or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0277] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0278] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0279] As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., base stations).

[0280] In the present disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," etc. may be used interchangeably.

[0281] In this disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "cell," "sector," "cell group," "carrier," "component carrier," etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0282] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0283] In the present disclosure, a base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control / operate based on the information.

[0284] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0285] A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0286] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a wireless communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc.

[0287] The mobile body is a movable object that can move at any speed and naturally includes cases where the mobile body is stationary. Examples of the mobile body include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and objects mounted thereon. The mobile body may also be a mobile body that moves autonomously based on an operation command.

[0288] The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Note that at least one of the base station and the mobile station may also include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0289] 17 is a diagram showing an example of a vehicle according to an embodiment. Vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, an electronic control unit 49, various sensors (including a current sensor 50, an RPM sensor 51, an air pressure sensor 52, a vehicle speed sensor 53, an acceleration sensor 54, an accelerator pedal sensor 55, a brake pedal sensor 56, a shift lever sensor 57, and an object detection sensor 58), an information service unit 59, and a communication module 60.

[0290] The drive unit 41 is configured with at least one of an engine, a motor, and a hybrid of an engine and a motor, for example. The steering unit 42 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on the operation of the steering wheel operated by the user.

[0291] The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and a communication port (e.g., an input / output (IO) port) 63. Signals are input to the electronic control unit 49 from various sensors 50-58 provided in the vehicle. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

[0292] The signals from the various sensors 50-58 include a current signal from a current sensor 50 that senses the current of the motor, a rotation speed signal of the front wheels 46 / rear wheels 47 obtained by a rotation speed sensor 51, an air pressure signal of the front wheels 46 / rear wheels 47 obtained by an air pressure sensor 52, a vehicle speed signal obtained by a vehicle speed sensor 53, an acceleration signal obtained by an acceleration sensor 54, a depression amount signal of the accelerator pedal 43 obtained by an accelerator pedal sensor 55, a depression amount signal of the brake pedal 44 obtained by a brake pedal sensor 56, an operation signal of the shift lever 45 obtained by a shift lever sensor 57, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 58.

[0293] The information service unit 59 is composed of various devices, such as a car navigation system, an audio system, speakers, a display, a television, and a radio, for providing (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 59 uses information acquired from external devices via the communication module 60 or the like to provide various information / services (for example, multimedia information / multimedia services) to the occupants of the vehicle 40.

[0294] The information service unit 59 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0295] The driving assistance system unit 64 is configured with various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Units (IMUs), Inertial Navigation Systems (INSs)), Artificial Intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driving assistance functions or autonomous driving functions.

[0296] The communication module 60 can communicate with the microprocessor 61 and components of the vehicle 40 via the communication port 63. For example, the communication module 60 transmits and receives data (information) via the communication port 63 to and from the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and the various sensors 50-58, which are provided in the vehicle 40.

[0297] The communication module 60 is a communication device that can be controlled by the microprocessor 61 of the electronic control unit 49 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 60 may be located either inside or outside the electronic control unit 49. The external device may be, for example, the above-mentioned base station 10 or user terminal 20. Furthermore, the communication module 60 may be, for example, at least one of the above-mentioned base station 10 and user terminal 20 (or may function as at least one of the base station 10 and user terminal 20).

[0298] The communication module 60 may transmit at least one of signals from the above-mentioned various sensors 50-58 input to the electronic control unit 49, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 59 to an external device via wireless communication. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include information based on the above-mentioned input.

[0299] The communication module 60 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on an information service unit 59 provided in the vehicle. The information service unit 59 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH received by the communication module 60 (or data / information decoded from the PDSCH)).

[0300] Furthermore, the communication module 60 stores various information received from external devices in a memory 62 that can be used by the microprocessor 61. Based on the information stored in the memory 62, the microprocessor 61 may control the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, various sensors 50-58, and the like provided in the vehicle 40.

[0301] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "sidelink"). For example, terms such as uplink channel and downlink channel may be read as sidelink channel.

[0302] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0303] In the present disclosure, an operation described as being performed by a base station may be performed by its upper node in some cases. It is apparent that in a network including one or more network nodes having a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (such as, but not limited to, a Mobility Management Entity (MME) and a Serving-Gateway (S-GW)), or a combination thereof.

[0304] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, the order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the specific order presented.

[0305] Each aspect / embodiment described in the present disclosure may be a technology other than Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG (x is, for example, an integer or decimal number)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE The present invention may be applied to systems that use 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other appropriate wireless communication methods, or to next-generation systems that are expanded, modified, created, or defined based on these. It may also be applied to a combination of multiple systems (e.g., a combination of LTE or LTE-A and 5G).

[0306] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0307] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0308] The term "determining," as used in this disclosure, may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, etc.

[0309] Additionally, "determining" may be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

[0310] Also, "decision" may be considered to be "deciding" resolving, selecting, choosing, establishing, comparing, etc. In other words, "decision" may be considered to be "deciding" on some action.

[0311] Furthermore, "judgment (decision)" may be interpreted as "assuming," "expecting," "considering," or the like.

[0312] The "maximum transmit power" in this disclosure may mean the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0313] As used in this disclosure, the terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

[0314] In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

[0315] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0316] When used in this disclosure, the terms "include," "including," and variations thereof are intended to be inclusive, similar to the term "comprising." Furthermore, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0317] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0318] In the present disclosure, terms such as "less than or equal to," "less than," "greater than," "more than," "equal to," etc. may be interchangeable. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative, as expressions with the prefix "i-th" (i is any integer) (for example, "highest" may be interchangeable as "i-th highest").

[0319] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0320] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The invention according to the present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the description of the claims. Therefore, the description of the present disclosure is intended to be illustrative and explanatory and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. A receiver that receives downlink control information (DCI) indicating a port of a second demodulation reference signal (DMRS) of a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied; A control unit that controls reception or transmission of the second DMRS, A terminal, wherein one value of the information for indicating a port for the second DMRS is associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

2. The terminal of claim 1 , wherein the information is an antenna port field.

3. The terminal of claim 2 , wherein whether the antenna port field refers to an association for the first DMRS or an association for the second DMRS is configured by higher layer signaling.

4. receiving downlink control information (DCI) indicating a port of a second demodulation reference signal (DMRS) of a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied; and controlling reception or transmission of the second DMRS; A wireless communication method for a terminal, wherein one value of the information for indicating a port for the second DMRS is associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

5. a transmitter that transmits downlink control information (DCI) indicating a port of a second DMRS of a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied; A control unit that controls reception or transmission of the second DMRS, A base station, wherein one value of the information for indicating a port for the second DMRS is associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

6. A system having a terminal and a base station, The terminal includes a receiver that receives downlink control information (DCI) indicating a port of a second DMRS among a first demodulation reference signal (DMRS) to which a first frequency domain orthogonal cover code (FD-OCC) of length 2 is applied and a second DMRS to which a second FD-OCC longer than 2 is applied; A control unit that controls reception or transmission of the second DMRS, The base station includes a transmitter that transmits the DCI; A control unit that controls reception or transmission of the second DMRS, A system, wherein one value of the information for indicating a port for the second DMRS is associated with one or more ports for the first DMRS and one or more ports for the second DMRS.

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