Method and apparatus for transmitting and receiving DMRS in a wireless communication system

Abstract

A method performed by a terminal according to an embodiment of the present specification includes receiving configuration information related to DMRS, receiving DCI for scheduling a PDSCH, receiving the DMRS for the PDSCH, and receiving the PDSCH. When the DMRS configuration is based on the enhanced DMRS type, and the value indicated in the antenna port field is 2, remaining orthogonal antenna ports based on the same CDM group are assigned to other terminals configured with the enhanced DMRS type. It is characterized by being related to PDSCH transmission.

Description

[Technical Field]

[0001] The present specification relates to a method and apparatus for transmitting and receiving a DMRS in a wireless communication system. [Background technology]

[0002] Mobile communication systems were developed to provide voice services while ensuring user activity. However, the scope of mobile communication systems has expanded beyond voice to include data services, and currently, explosive traffic growth is causing resource shortages and users are demanding faster services, so more advanced mobile communication systems are required.

[0003] The requirements for next-generation mobile communication systems are significant: they must be able to accommodate explosive data traffic, dramatically increase the transmission rate per user, accommodate a significantly increased number of connected devices, provide extremely low end-to-end latency, and support high energy efficiency. To achieve this, various technologies are being researched, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking.

[0004] On the other hand, multi-UE scheduling can be restricted as follows: If a specific value (e.g., value 2 -> [CDM group 1, ports 0 & 1]) among the values ​​defined by the DMRS type table is indicated by the antenna port field, all remaining orthogonal antenna ports are not associated with PDSCH transmission for other UEs. Summary of the Invention [Problem to be solved by the invention]

[0005] With the Rel-18 enhancement, the number of DMRS ports has doubled compared to the previous version. As mentioned above, if MU scheduling is limited as in the previous method, it can act as a constraint on maximizing the use of the increased antenna ports.

[0006] This specification proposes a method for solving the above-mentioned problems.

[0007] The technical problems to be solved in this specification are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the description below. [Means for solving the problem]

[0008] In one embodiment of the present specification, a method performed by a terminal in a wireless communication system includes (comprises; configures; establishes; sets up; encompasses; contains; has) the steps of receiving configuration information related to a demodulation reference signal (DMRS), receiving downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH), receiving the DMRS for the PDSCH, and receiving the PDSCH.

[0009] The DMRS configuration based on the configuration information is based on the DMRS type or enhanced (enhance) DMRS type. The DCI includes an antenna port field. The antenna port field indicates one of the values ​​defined by a table.

[0010] Each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port.

[0011] Two of the values ​​defined in the table are associated with one CDM group and antenna ports 1000, 1001.

[0012] The DMRS configuration is based on the DMRS type, and the value indicated based on the antenna port field is 2: the remaining orthogonal antenna ports are not associated with PDSCH transmission to other terminals.

[0013] When the DMRS configuration is based on the enhanced DMRS type, the value indicated in the antenna port field is 2: the remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS type.

[0014] The DMRS type may be DMRS type 1 or DMRS type 2. The enhanced DMRS type may be enhanced DMRS type 1 or enhanced DMRS type 2.

[0015] For the DMRS type 1, i) antenna ports 1000 to 1003, or ii) antenna ports 1000 to 1003 and 1008 to 1011 can be supported.

[0016] For the DMRS TYPE 2, i) antenna ports 1000 to 1005 or ii) antenna ports 1000 to 1011 can be supported.

[0017] For the enhanced DMRS TYPE 1, i) antenna ports 1000 to 1003, 1008 to 1011, or ii) antenna ports 1000 to 1015 may be supported.

[0018] For the enhanced DMRS TYPE 2, i) antenna ports 1000 to 1005 and 1012 to 1017, or ii) antenna ports 1000 to 1023 can be supported.

[0019] The table may be one of a plurality of tables determined based on i) the DMRS configuration and ii) a maximum number of symbols associated with the DMRS.

[0020] The plurality of tables may include i) a first table, a second table, a third table, and a fourth table associated with the DMRS type, and ii) a fifth table, a sixth table, a seventh table, and an eighth table associated with the enhanced DMRS type.

[0021] Based on the DMRS configuration being DMRS type 1 and the maximum number being 1, the table may be determined as the first table.

[0022] Based on the fact that the DMRS configuration is enhanced DMRS type 1 and the maximum number is 1, the table may be determined as the fifth table.

[0023] The fifth table may include i) a first value defined in the first table and ii) a second value.

[0024] Each of the first values ​​may be associated with at least one of the antenna ports 1000-1003.

[0025] Each of the second values ​​may be associated with at least one of the antenna ports 1008-1011.

[0026] A particular one of the first values ​​may be associated with one CDM group and antenna port 1000, 1001. A particular one of the second values ​​may be associated with one CDM group and antenna port 1008, 1009.

[0027] Based on the DMRS configuration being based on the enhanced DMRS type 1 and the value indicated based on the antenna port field being the specific second value: remaining orthogonal antenna ports based on the same CDM group can be associated with PDSCH transmission for other terminals configured with the enhanced DMRS type 1.

[0028] The fifth table may further include third values ​​associated with three or more antenna ports among the antenna ports 1000 to 1011. A particular third value among the third values ​​may be associated with one CDM group and antenna ports 1000, 1001, 1008, and 1009.

[0029] Based on the DMRS configuration being based on the enhanced DMRS type 1 and the value indicated based on the antenna port field being the specific third value: the remaining orthogonal antenna ports may not be associated with PDSCH transmission to other terminals.

[0030] A terminal operating in a wireless communication system according to another embodiment of the present specification includes one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and configured to store instructions.

[0031] The instructions, when executed by the one or more processors, configure the one or more processors to perform all of the steps of any one of the methods.

[0032] According to still another embodiment of the present disclosure, an apparatus includes one or more memories and one or more processors operatively coupled to the one or more memories.

[0033] The one or more memories are characterized by storing instructions that, when executed by the one or more processors, cause the one or more processors to perform all steps of any one of the methods.

[0034] In accordance with still other embodiments of the present disclosure, one or more non-transitory computer-readable media store instructions executable by one or more processors to configure the one or more processors to perform all of the steps of any one of the methods.

[0035] According to another embodiment of the present specification, a method performed by a base station in a wireless communication system includes transmitting configuration information related to a demodulation reference signal (DMRS), transmitting downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH), transmitting the DMRS for the PDSCH, and transmitting the PDSCH.

[0036] The DMRS configuration based on the configuration information is based on the DMRS type or the enhanced DMRS type. The DCI includes an antenna port field. The antenna port field indicates one of the values ​​defined by a table.

[0037] Each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port.

[0038] Of the values ​​defined in the table, 2 is associated with one CDM group and antenna ports 1000, 1001.

[0039] The DMRS configuration is based on the DMRS type, and the value indicated based on the antenna port field is 2: the remaining orthogonal antenna ports are not associated with PDSCH transmission to other terminals.

[0040] When the DMRS configuration is based on the enhanced DMRS type, the value indicated in the antenna port field is 2: the remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS type.

[0041] A base station operating in a wireless communication system according to another embodiment of the present specification includes one or more transceivers, one or more processors, and one or more memories coupled to the one or more processors and configured to store instructions.

[0042] The instructions, when executed by the one or more processors, configure the one or more processors to perform all of the steps of the method. [Effects of the Invention]

[0043] According to the embodiments of the present specification, the same values ​​as previously defined (values ​​related to the same number of CDM groups and antenna ports as conventional) are used for the DMRS type and enhanced DMRS type, but a specific value indicated by the antenna port field (e.g., a value that restricts MU scheduling for a DMRS type) allows MU scheduling for the enhanced DMRS type. Therefore, it is possible to maximize the scheduling performance based on the enhanced DMRS type while minimizing implementation complexity.

[0044] The effects obtained in this specification are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those having ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawings]

[0045] [Figure 1] 1 is a flowchart illustrating an example of a DL DMRS procedure. [Figure 2] 10 shows an example of a downlink transmission and reception operation. [Figure 3] 1 is a flowchart illustrating a method performed by a terminal according to an embodiment of the present specification. [Figure 4] 10 is a flowchart illustrating a method performed by a base station according to another embodiment of the present disclosure. [Figure 5] 1 is a diagram illustrating the configuration of a first device and a second device according to an embodiment of the present specification. DETAILED DESCRIPTION OF THE INVENTION

[0046] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The detailed description disclosed below, together with the accompanying drawings, is intended to describe exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention can be practiced. The following detailed description includes specific details to provide a thorough understanding of the present invention. However, those skilled in the art will recognize that the present invention can be practiced without such specific details.

[0047] In some cases, well-known structures and devices may be omitted or shown in block diagram form, focusing on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention.

[0048] Hereinafter, downlink (DL) refers to communication from a base station to a terminal, and uplink (UL) refers to communication from a terminal to a base station. In the downlink, the transmitter may be part of the base station, and the receiver may be part of the terminal. In the uplink, the transmitter may be part of the terminal, and the receiver may be part of the base station. The base station may also be expressed as a first communication device, and the terminal as a second communication device. A base station (BS) may be replaced with terms such as a fixed station, Node B, evolved Node B (eNB), Next Generation Node B (gNB), base transceiver system (BTS), access point (AP), network (5G network), AI system, road side unit (RSU), vehicle, robot, unmanned aerial vehicle (UAV), augmented reality (AR) device, and virtual reality (VR) device. In addition, a terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, robot, AI module, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, and VR (Virtual Reality) device.

[0049] DMRS (demodulation reference signal)

[0050] DMRS reception procedure

[0051] A careful look at the DMRS related operations for receiving PDSCH.

[0052] When receiving a PDSCH scheduled by DCI format 1_0, or dmrs‐AdditionalPosition, maxLength and dmrs‐Type When receiving a PDSCH before any dedicated upper layer configuration of parameters, the terminal assumes that there is no PDSCH in any symbol carrying a DM-RS except for a PDSCH with a 2-symbol allocation duration having PDSCH mapping type B, that a single-symbol front-loaded DM-RS of configuration type 1 is transmitted on DM-RS port 1000, and that all remaining orthogonal antenna ports are not associated with transmitting PDSCHs to other terminals.

[0053] Additionally, for a PDSCH with mapping type A, the terminal assumes that dmrs-AdditionalPosition='pos2' and up to two additional single-symbol DM-RSs are present in the slot according to the PDSCH duration indicated in the DCI. For a PDSCH with an allocation duration of 7 symbols for a normal CP or 6 symbols for an extended CP with mapping type B, when a frontloaded DM-RS symbol is in the first or second symbol of the PDSCH allocation duration, the terminal assumes that one additional single-symbol DM-RS is present in the fifth or sixth symbol. Otherwise, the terminal assumes that no additional DM-RS symbols are present. Then, for a PDSCH with an allocation duration of 4 symbols with mapping type B, the terminal assumes that no additional DM-RSs are present. For a PDSCH with an allocation duration of 2 symbols with mapping type B, the terminal assumes that no additional DM-RSs are present and that the PDSCH is present in the symbol carrying the DM-RS.

[0054] When receiving a PDSCH scheduled by DCI format 1_1 by a PDCCH having a CRC scrambled by a C-RNTI, an MCS-C-RNTI, or a CS (configured scheduling)-RNTI,

[0055] - The terminal may be configured with the upper layer parameter dmrs-Type, and the configured DM-RS configuration type is used to receive the PDSCH.

[0056] The terminal may be configured with the maximum number of front-loaded DM-RS symbols for the PDSCH by the upper layer parameter maxLength provided by the DMRS-DownlinkConfig.

[0057] The terminal can be scheduled for the number of DM-RS ports according to the antenna port index of DCI format 1_1.

[0058] The DMRS configuration type is set by the dmrs-Type parameter in the DMRS-DownlinkConfig IE in Table 1. DMRS configuration type 1 has higher RS ​​density in the frequency domain and supports up to 4 (8) ports for single (double)-symbol DMRS. DMRS configuration type 1 also supports length 2F-CDM and FDM for single-symbol DMRS and length 2F / T-CDM and FDM for double-symbol DMRS. DMRS configuration type 2 supports more DMRS antenna ports and supports up to 6 (12) ports for single (double)-symbol DMRS.

[0059] Table 1 below shows an example of a DMRS-DownlinkConfig IE used to configure downlink DMRS for a PDSCH.

[0060] [Table 1]

[0061] In Table 1, the dmrs-AdditionalPosition parameter indicates the position for the additional DM-RS in DL, and if this parameter does not exist, the terminal applies the pos2 value. The Dmrs-Type parameter indicates the selection of the DMRS type to be used in DL, and if this parameter does not exist, the terminal uses DMRSTYPE1. The Max-Length parameter indicates the maximum number of OFDM symbols for DL ​​front loaded DMRS, and len1 corresponds to a value of 1. The PhaseTrackingRS parameter configures DL PTRS, and if this parameter does not exist or is cleared, the terminal assumes that there is no DL PTRS.

[0062] The dmrs‐TypeEnh parameter enables the use of enhanced DMRS type 1 or enhanced DMRS type 2. If the dmrs‐TypeEnh parameter is set and dmrs‐TypeEnh is not set, the terminal uses enhanced DMRS type 1 (DMRS eType 1). If the dmrs‐TypeEnh parameter and dmrs‐Type are set, the terminal uses enhanced DMRS type 2 (DMRS eType 2).

[0063] Regarding DM‐RS configuration type 1,

[0064] If the terminal is scheduled with one codeword and the antenna port mapping is assigned to an index of {2, 9, 10, 11, or 30}, or if the terminal is scheduled with two codewords,

[0065] The terminal may assume that all of the remaining orthogonal antenna ports are not associated with transmitting PDSCH to other terminals.

[0066] Regarding DM-RS configuration type 2,

[0067] If the terminal is scheduled for one codeword and the antenna port mapping is assigned to an index of {2,10,23}, or if the terminal is scheduled for two codewords,

[0068] The terminal may assume that all of the remaining orthogonal antenna ports are not associated with transmitting PDSCH to other terminals.

[0069] FIG. 1 is a flowchart illustrating an example of a DL DMRS procedure.

[0070] The base station transmits DMRS configuration information to the terminal (S110).

[0071] The DMRS configuration information may refer to a DMRS-DownlinkConfig IE, which may include a dmrs-Type parameter, a dmrs-AdditionalPosition parameter, a maxLength parameter, a phaseTrackingRS parameter, and the like.

[0072] The dmrs-Type parameter is a parameter for selecting the DMRS configuration type used for DL. In NR, DMRS can be divided into two configuration types: (1) DMRS configuration type 1 and (2) DMRS configuration type 2. DMRS configuration type 1 has higher RS ​​density in the frequency domain, and DMRS configuration type 2 has more DMRS antenna ports.

[0073] The dmrs-AdditionalPosition parameter indicates the position of an additional DMRS in DL. If this parameter does not exist, the UE applies the value of pos2. The first position of the front-loaded DMRS is determined according to the PDSCH mapping type (Type A or Type B), and an additional DMRS can be configured to support high-speed UEs. The front-loaded DMRS occupies one or two consecutive OFDM symbols and is indicated by RRC signaling and downlink control information (DCI).

[0074] The maxLength parameter indicates the maximum number of OFDM symbols for DL ​​front-loaded DMRS. The phaseTrackingRS parameter is a parameter for setting DL PTRS. If the parameter does not exist or is cleared, the UE assumes that there is no DL PTRS.

[0075] The base station generates a sequence to be used for the DMRS (S120).

[0076] The DMRS sequence is generated according to Equation 1 below.

[0077]

number

[0078] The pseudo-random sequence c(i) is defined in 3GPP TS 38.211 5.2.1. That is, c(i) can be a Gold sequence of length 31 using two m-sequences. The pseudo-random sequence generator is initialized by the following Equation 2:

[0079]

number

[0080] The base station maps the generated sequence to resource elements (S130), where a resource element may mean at least one of a time, a frequency, an antenna port, or a code.

[0081] The base station transmits the DMRS to the terminal on the resource elements (S140), and the terminal receives a PDSCH using the received DMRS.

[0082] UE DMRS transmission procedure

[0083] Let's take a closer look at the DMRS-related operations for receiving PUSCH. As you can see, UL means signal transmission (or communication) from the terminal to the base station. UL DMRS-related operations are similar to the DL DMRS-related operations we looked at earlier, and the names of the DL-related parameters can be replaced with the names of the UL-related parameters.

[0084] That is, the DMRS-DownlinkConfig IE can be replaced with the DMRS-UplinkConfig IE, the PDSCH mapping type can be replaced with the PUSCH mapping type, and the PDSCH can be replaced with the PUSCH. In DL DMRS-related operations, the base station can be replaced with the UE, and the UE can be replaced with the base station. The sequence generation for the UL DMRS can be defined differently depending on whether transform precoding is enabled.

[0085] More specifically, DMRS uses a PN sequence when using cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) (or when transform precoding is not enabled), and uses a ZC sequence with a length of 30 or more when using Discrete Fourier Transform-spread-OFDM (DFT-s-OFDM) (when transform precoding is enabled).

[0086] Table 2 below shows an example of a DMRS-UplinkConfigIE used to configure an uplink DMRS for a PUSCH.

[0087] [Table 2]

[0088] In Table 2, the dmrs-AdditionalPosition parameter indicates the position of the additional DM-RS in the UL; if this parameter does not exist, the terminal applies the value pos2. The DMRS-Type parameter indicates the selection of the DMRS type to be used for the UL; if this parameter does not exist, the terminal uses DMRS type 1.

[0089] The Max-Length parameter indicates the maximum number of OFDM symbols for UL front loaded DMRS, and len1 corresponds to a value of 1. The PhaseTrackingRS parameter sets the UL PTRS. The transformPrecodingdisabled parameter indicates DMRS-related parameters for Cyclic Prefix OFDM. The transformPrecodingEnabled parameter indicates DMRS-related parameters for DFT-S-OFDM (Transform Precoding).

[0090] The UE DM-RS transmission procedure will now be looked at in more detail.

[0091] If the transmitted PUSCH is not scheduled by DCI format 0_1 ​​having a CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI, and may not correspond to a configured grant, the UE uses a single-symbol front-loaded DM-RS of configuration type 1 in DM-RS port 0, and the remaining REs not used for the DM-RS in the symbol are not used for any PUSCH transmission except for a PUSCH having an allocation duration of two or less OFDM symbols with disabled transform precoding. Additional DM-RS may be transmitted according to the scheduling type and PUSCH duration, taking into account whether frequency hopping is enabled.

[0092] If frequency hopping is disabled: The terminal assumes that dmrs-AdditionalPosition is equal to "pos2" and that up to two Additional DM-RSs can be transmitted according to the PUSCH duration.

[0093] If frequency hopping is enabled: The terminal assumes that dmrs-AdditionalPosition is equal to "pos1" and that at most one additionalDM-RS can be transmitted according to the PUSCH duration.

[0094] When the transmitted PUSCH is scheduled by activation DCI format 0_0 with a CRC scrambled by the CS-RNTI, the terminal uses a single-symbol front-loaded DM-RS of the configuration type provided by the upper layer parameter dmrs-Type of configuredGrantConfig on DM-RS port 0, and the remaining REs not used for the DM-RS in the symbol are not used for any PUSCH transmission except for a PUSCH with an allocation duration of two or less OFDM symbols with disabled transform precoding, and an additional DM-RS with dmrs-AdditionalPosition from configuredGrantConfig can be transmitted based on the scheduling type and PUSCH duration, taking into account whether frequency hopping is enabled.

[0095] When the transmitted PUSCH corresponds to a scheduled or configured grant according to DCI format 0_1 ​​with a CRC scrambled by the C-RNTI, CS-RNTI, or MCS-RNTI,

[0096] - The terminal can set the upper layer parameter dmrs-Type in DMRS-UplinkConfig, and the set DM-RS configuration type is used for PUSCH transmission.

[0097] The terminal can be configured with the maximum number of front-loaded DM-RS symbols for the PUSCH by the upper layer parameter maxLength in the DMRS-Uplink Config.

[0098] If a terminal transmitting a PUSCH is configured with the upper layer parameter phaseTrackingRS in DMRS-UplinkConfig, the terminal can assume that the next configuration does not occur simultaneously for the transmitted PUSCH.

[0099] - For DM-RS configuration type 1 and type 2, any DM-RS port among 4-7 or 6-11 is scheduled for the UE, and the PT-RS is transmitted from the terminal.

[0100] For a PUSCH scheduled by DCI format 0_1, by activated DCI format 0_1 ​​with CRC scrambled by CS-RNTI or by configured grant type 1 setting, the terminal assumes that the DM-RS CDM group is not used for data transmission.

[0101] In the following, we will carefully consider downlink and uplink transceiver operations in turn.

[0102] Downlink transmit / receive operation

[0103] FIG. 2 shows an example of downlink transmission and reception operations.

[0104] The base station schedules downlink transmission, including frequency / time resources, transmission layers, downlink precoders, MCSs, etc. (S210). As an example, the base station can determine a beam for transmitting a PDSCH to a terminal.

[0105] The terminal receives downlink control information (DCI) for downlink scheduling (ie, including scheduling information of the PDSCH) from the base station on the PDCCH (S220).

[0106] DCI format 1_0 or DCI format 1_1 is used for downlink scheduling, and DCI format 1_1 includes the following exemplary information: For example, DCI format 1_1 includes at least one of a DCI format identifier, a bandwidth part indicator, a frequency domain resource assignment, a time domain resource assignment, a PRB bundling size indicator, a rate matching indicator, a ZP CSI-RS trigger, antenna port(s), a transmission configuration indication (TCI), an SRS request, and a DMRS (Demodulation Reference Signal) sequence initialization.

[0107] In particular, for each state indicated in the Antenna port(s) field, the number of DMRS ports can be scheduled, and SU (Single-user) / MU (Multi-user) transmission scheduling is possible.

[0108] The TCI field is composed of 3 bits, and by indicating up to eight TCI states according to the TCI field value, the QCL for the DMRS can be dynamically indicated.

[0109] The terminal receives downlink data from the base station on the PDSCH (S230).

[0110] When the UE detects a PDCCH including DCI format 1_0 or 1_1, the UE can decode the PDSCH according to the instruction of the corresponding DCI. Here, when the UE receives a PDSCH scheduled according to DCI format 1, the UE is configured with a DMRS configuration type according to an upper layer parameter 'dmrs-Type', and the DMRS type is used to receive the PDSCH. In addition, the UE is configured with a maximum number of DMRS symbols to be inserted before (front-loaded) for the PDSCH according to an upper layer parameter 'maxLength'.

[0111] In the case of DMRS configuration type 1, if a terminal is scheduled with a single codeword and an antenna port mapped with an index of {2, 9, 10, 11, or 30} is specified, or if a terminal is scheduled with two codewords, the terminal assumes that all remaining orthogonal antenna ports are also not involved in PDSCH transmission to other terminals. Alternatively, in the case of DMRS configuration type 2, if a terminal is scheduled with a single codeword and an antenna port mapped with an index of {2, 10, or 23} is specified, or if a terminal is scheduled with two codewords, the terminal assumes that all remaining orthogonal antenna ports are also not involved in PDSCH transmission to other terminals.

[0112] When a terminal receives a PDSCH, it can assume that a precoding granularity P' is a contiguous resource block in the frequency domain. Here, P' corresponds to one of the values ​​{2, 4, wideband}. If P' is determined to be wideband, the terminal does not expect to be scheduled with non-contiguous PRBs, and it can assume that the same precoding is applied to the assigned resources. On the other hand, if P' is determined to be one of {2, 4}, a precoding resource block group (PRG) is divided into P' contiguous PRBs. The number of actual contiguous PRBs in each PRG can be one or more. The UE can assume that the same precoding is applied to consecutive downlink PRBs in a PRG.

[0113] In order for the UE to determine the modulation order, target code rate, and transport block size in the PDSCH, the UE first reads the 5-bit MCD field in the DCI to determine the modulation order and target code rate. The UE can then read the redundancy version field in the DCI to determine the redundancy version. The UE can then determine the transport block size using the number of layers and the total number of allocated PRBs before rate matching.

[0114] Uplink transmit and receive operations

[0115] The base station schedules uplink transmissions such as frequency / time resources, transmission layers, uplink precoders, MCS, etc. In particular, the base station can determine a beam for PUSCH transmission by the terminal through a beam management operation. Then, the terminal receives DCI for uplink scheduling (i.e., including PUSCH scheduling information) from the base station on the PDCCH. For uplink scheduling, DCI format 0_0 or 0_1 can be used. In particular, DCI format 0_1 ​​includes the following information: DCI format identifier (Identifier for DCI formats), UL / SUL (Supplementary uplink) indicator (UL / SUL indicator), Bandwidth part indicator, Frequency domain resource assignment, Time domain resource assignment, Frequency hopping flag, Modulation and coding scheme (MCS), SRS resource indicator (SRI), Precoding information and number of layers, Antenna port(s), SRS request, DMRS sequence initialization, and UL-SCH (Uplink Shared Channel) indicator.

[0116] In particular, the SRS resource indicator field can indicate the SRS resource set in the SRS resource set associated with the upper layer parameter 'usage'. In addition, 'spatialRelationInfo' can be set for each SRS resource, and its value can be one of {CRI, SSB, SRI}.

[0117] The UE then transmits uplink data to the base station over the PUSCH. If the UE detects a PDCCH containing DCI format 0_0 or 0_1, it transmits the corresponding PUSCH according to the instruction of the corresponding DCI. Two transmission methods are supported for PUSCH transmission: codebook-based transmission and non-codebook-based transmission.

[0118] For codebook-based transmission, when the upper layer parameter "txConfig" is set to "codebook," the terminal is configured for codebook-based transmission. On the other hand, when the upper layer parameter "txConfig" is set to "nonCodebook," the terminal is configured for non-codebook-based transmission. If the upper layer parameter "txConfig" is not set, the terminal does not expect to be scheduled by DCI format 0_1. When the PUSCH is scheduled by DCI format 0_0, PUSCH transmission is based on a single antenna port. For codebook-based transmission, the PUSCH can be scheduled by DCI format 0_0, DCI format 0_1, or semi-statically. When this PUSCH is scheduled by DCI format 0_1, the terminal determines a PUSCH transmit precoder based on the SRI, TPMI (Transmit Precoding Matrix Indicator), and transmission rank from the DCI, as given by the SRS resource indicator field and the Precoding information and number of layers field. The TPMI is used to indicate the precoder to be applied across antenna ports and corresponds to the SRS resource selected by the SRI when multiple SRS resources are configured. Alternatively, when a single SRS resource is configured, the TPMI is used to indicate the precoder to be applied across antenna ports and corresponds to the single SRS resource. A transmission precoder is selected from an uplink codebook having the same number of antenna ports as the upper layer parameter "nrofSRS-Ports." When the upper layer in which the terminal is set to "codebook" is set to the parameter "txConfig," at least one SRS resource is configured in the terminal. The SRI indicated in slot n relates to the most recent transmission of the SRS resource identified by the SRI, where the SRS resource precedes the PDCCH (i.e., slot n) carrying the SRI.

[0119] For non-codebook-based transmission, the PUSCH can be scheduled using DCI format 0_0, DCI format 0_1, or semi-statically. When multiple SRS resources are configured, the terminal can determine the PUSCH precoder and transmission rank based on the wideband SRI, where the SRI is given by the SRS resource indicator in the DCI or the upper layer parameter "srs-ResourceIndicator." The terminal uses one or multiple SRS resources for SRS transmission, where the number of SRS resources can be configured for simultaneous transmission within the same RB based on UE capabilities. Only one SRS port is configured for each SRS resource. Only one SRS resource can be configured with the upper layer parameter "usage" set to "nonCodebook." The maximum number of SRS resources that can be configured for non-codebook-based uplink transmission is four. An SRI designated in slot n is associated with the most recent transmission on the SRS resource identified by the SRI, where the SRS transmission precedes the PDCCH (ie, slot n) carrying the SRI.

[0120] The contents carefully reviewed above (DMRS, DL transmission / reception operation, etc.) may be applied in combination with the methods proposed in this specification, which will be described later, or may be supplemented to clarify the technical features of the methods proposed in this specification. The methods described below are only divided for the convenience of explanation, and it goes without saying that some components of any method may be replaced with some components of other methods, or may be applied in mutual combination.

[0121] In this specification, the terms "port" and "antenna port" may be interpreted interchangeably. For example, a DMRS port may refer to a DMRS antenna port, and vice versa.

[0122] In this specification, "DMRS" can mean "DM-RS" and vice versa.

[0123] When scheduling one codeword to a UE during DMRS configuration, a specific DMRS port index is used / configured only in the SU. As an example, when a specific DMRS port index is indicated / assigned to a UE, the remaining orthogonal DMRS port indexes are not associated with PDSCH transmissions for other UEs. As an example, when a specific DMRS port index is indicated / assigned to a UE, the remaining orthogonal DMRS port indexes in the CDM group based on the indicated DMRS port index are not associated with PDSCH transmissions for other UEs. The specific DMRS port index may include one or more DMRS port indexes.

[0124] As described above, when a PDSCH is scheduled for one UE (when a DMRS port(s) is indicated by the antenna port field of the DCI that schedules the PDSCH), the remaining orthogonal DMRS port(s) excluding the indicated DMRS port(s) / the remaining orthogonal DMRS ports in the indicated CDM group(s) may not be associated with PDSCH transmission for other UEs.

[0125] As described above, when a specific DMRS port "port(s)" is indicated for a certain UE, the case where PDSCH scheduling for other UEs is restricted can be referred to as follows in this specification: "the specific DMRS port is used only for SU (Single UE)", "the specific DMRS port is not used for MU (Multi-UE)", or "MU restriction".

[0126] In this specification, when a DMRS port index(es) corresponding to SU 'only' is indicated, the remaining DMRS port index(es) excluding the indicated DMRS port index(es) can be interpreted as "DMRS port index(es) that cannot be used for scheduling MU / Multi-UEs."

[0127] In this specification, when a specific DMRSport / port index is not available for MUs, it can mean that the specific DMRSport / port index is used only for SUs. Furthermore, when a specific DMRSport / port index is indicated, it can mean that the remaining DMRSport / port indexes are not used for MUs.

[0128] In this specification, the DMRS port indicated by the antenna port field of the DCI for scheduling the PDSCH may be interpreted / substituted as a port, an antenna port, or a DMRS antenna port. As an example, "port" may be interpreted / substituted as a DMRS port, an antenna port, or a DMRS antenna port.

[0129] In this specification, ports 0 to 15 can be interpreted / substituted as ports 1000 to 1015, and ports 0 to 23 can be interpreted / substituted as ports 1000 to 1023.

[0130] The supported ports for existing DMRS type 1 / 2 (DMRSconfiguration type1 / 2) are as follows:

[0131] [1] For single-symbol DMRS, i) ports 1000 to 1003 (Type 1) or ii) ports 1000 to 1005 (Type 2) are supported.

[0132] [2] "For double symbol DMRS, i) port 1000-1007 (type 1) or ii) port 1000-1011 (type 2) are supported.

[0133] The supported ports for enhanced DMRS type 1 / 2 (DMRSconfiguration enhanced type1 / 2) are:

[0134] [1] For single-symbol DMRS, i) ports 1000-1003, 1008-1011 (Type 1) or ii) ports 1000-1005, 1012-1017 (Type 2) are supported.

[0135] [2] For double symbol DMRS, i) ports 1000-1015 (Type 1) or ii) ports 1000-1023 (Type 2) are supported.

[0136] On the other hand, if two codewords are scheduled, all orthogonal DMRS ports for the PDSCH are used only for the SUs.

[0137] In Rel-18, the number of orthogonal DMRS ports is doubled. That is, referring to Table 3 below, the maximum number of ports supported for enhanced DMRS ports / enhanced DMRS TYPEs is twice the maximum number of ports supported for existing DMRS ports / DMRS TYPEs. Depending on the increased number of DMRS ports, changes to DMRS ports related to MU restriction (SU only) may be considered. This specification allows for more DMRS port combinations by removing or reducing restrictions on MU operation. We propose a method to flexibly utilize this in MU scheduling.

[0138] [Table 3]

[0139] Referring to the agreement in Table 3, it was agreed to double the maximum number of DMRS ports to increase the number of configurable DMRS ports. Furthermore, to this end, it was agreed to multiplex the increased DMRS ports by increasing the length of the previously defined Frequency Domain Orthogonal Cover Code (FD-OCC). Specifically, the length of the FD-OCC was increased from 2 to 4. The doubled DMRS ports are multiplexed based on the corresponding FD-OCC.

[0140] For the newly supported enhanced DMRS ports, the antenna port tables (Tables 5 to 12 below) defined for the existing DMRS ports need to be newly created taking into account SU-MIMO and MU-MIMO.

[0141] In particular, legacy standards below R17 do not allow MU for certain ports, and there are port combinations that are used only by SU. Port combinations based on enhanced DMRS TYPE (Rel-18) also need to be designed taking into account SU-only ports.

[0142] [Table 4]

[0143] Referring to Table 4, when scheduling a UE with one codeword during DMRS configuration, the orthogonal DMRS port index corresponding to a specific DMRS field value (e.g., the value of the antenna port field in the DCI for scheduling a PDSCH) is used only for the SU (PDSCH scheduling for Mu is not possible). In other words, the remaining orthogonal DMRS ports, excluding the DMRS port indicated for the UE, are not associated with PDSCH transmission for other UEs.

[0144] When a UE is scheduled with two codewords, all orthogonal DMRS ports are used only by SUs, not MUs, for PDSCH transmission. For convenience, DMRS port indexes are referred to as indexes, and DMRS field values ​​(antenna port field values) are referred to as values.

[0145] In legacy NR standards below R17, when DMRS type=1 and max length=1, the DMRS port table (antenna port table) supports 4 ports (see Tables 5 and 6 below).

[0146] When DMRS type=1 and max length=2, 8 ports are supported (see Tables 7 and 8 below).

[0147] When DMRS type=2 and max length=1, 6 ports are supported (see Tables 9 and 10 below).

[0148] When DMRS type=2 and max length=2, 12 ports are supported (see Tables 11 and 12 below).

[0149] [Table 5]

[0150] Table 6

[0151] Table 7

[0152] Table 8

[0153] Table 9

[0154] Table 10

[0155] Table 11

[0156] JPEG2026506614000015.jpg146148

[0157] Table 12

[0158] JPEG2026506614000017.jpg146149

[0159] According to the enhanced DMRS type supported in Rel-18, eight ports are supported. As a specific example, based on (enhanced) DMRS type = 1 and max length = 1, the DMRS port table can support eight ports. Table 13 below illustrates an antenna port table for the enhanced DMRS type. The antenna port tables defined for the increased DMRS ports can be divided into Cat. 1, Cat. 2, and Cat. 3.

[0160] Cat.1 reuses the legacy antenna port table, while Cat.2 is designed by applying an offset to Cat.1. Cat.3 includes port combinations that simultaneously indicate ports indicated by Cat.1 and Cat.2.

[0161] In this case, Cat.1 to Cat.3 are only references used to distinguish / reference the values ​​of the antenna port field in the new antenna port table, and are not information actually defined in the corresponding antenna port table. For example, in Table 13, values ​​0 to 11 can be divided into the first value of the antenna port field, values ​​12 to 23 can be divided into the second value of the antenna port field, and values ​​24 to 29 can be divided into the third value of the antenna port field.

[0162] [Table 13]

[0163] JPEG2026506614000019.jpg39148

[0164] Regarding the port combinations in square brackets "[ ]" in the new table, discussions were held on the following points. Specifically, discussions were held on the combinations of Number of DMRS CDM group(s) without data=1 excluding S-TRP, M-TRP combinations, and MU-related combinations.

[0165] The doubled number of orthogonal DMRS ports allows for changes to MU restrictions (i.e., changes to the settings / operations already defined for MU restrictions). Below, we will specifically describe a method for flexibly utilizing more DMRSport combinations for MU scheduling by removing or reducing restrictions on MU operation.

[0166] <Proposal 1>

[0167] According to the previously defined behavior, ports restricted to be used only for SUs are not scheduled for MUs (see Table 14 below). The New DMRSport table can be designed taking into account the ports of only the SUs.

[0168] For DMRS configuration enhanced type 1, the DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 8 to 11.

[0169] For DMRS configuration enhanced type 2, a DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 12 to 15.

[0170] [Table 14]

[0171] According to the existing defined behavior (legacy NR standard) in Rel-17 and below, the number of SU-only ports based on the maximum number of orthogonal ports per UE in MU-MIMO is limited according to the agreement in Table 15 below.

[0172] [Table 15]

[0173] According to existing operations (operation set for DMRS type), index {0, 1, 2} is indicated based on value {9}, and index {0, 1, 2, 3} is indicated based on value {10}. In other words, more than two ports (3 ports / 4 ports) are configured / indicated. Although the maximum number of orthogonal ports per UE is 2 in MU-MIMO for type 1 with 1-symbol DMRS, these are used only for SUs. In other words, ports (0-2 or 0-3) indicated based on values ​​{9} and {10} in the new DMRS table can only be used for SUs.

[0174] Index{0,1} is indicated based on Value{2}. In the case of DMRS TYPE, all ports capable of transmission within the corresponding CDM group are indicated, so it is used only by SUs. In the case of enhanced DMRS type, the number of DMRS ports within the corresponding CDM group is doubled from 2 to 4, and the previously defined restriction (DMRS type restriction) can be lifted. In other words, in the new table, value{2} does not need to be restricted to only SUs, as it indicates only a portion of the ports capable of transmission within the corresponding CDM group.

[0175] In the case of a Legacy DMRS table (e.g., DMRS configuration type 1 / 2), when port index {0, 1} with CDM group=1 is instructed to a UE, the remaining ports excluding the instructed port are not associated with PDSCH transmissions to other UEs.

[0176] In the case of a new DMRS DMRS table (e.g., for DMRS configuration enhanced type 1 / 2), when port index {0, 1} with CDM group = 1 is indicated, the UE may not assume that all other orthogonal ports are not associated with PDSCH transmission to other UEs, or the UE may make no assumptions about all remaining orthogonal ports.

[0177] Index {0, 1} with CDM group=1 based on value {2} is capable of MU scheduling. In other words, for enhanced DMRS type 1 / 2, the remaining ports (e.g., ports 8-9) in the corresponding CDM group other than ports 0-1 with one CDM group indicated based on value {2} can be associated with PDSCH transmission to other UEs.

[0178] If the DMRS type is enhanced DMRS type (1 / 2), MU scheduling is restricted as shown in Table 16 below (only value{2}:index {0, 1}with CDM group = 1 is excluded from the MU scheduling restriction).

[0179] Table 16 below illustrates MU scheduling restrictions (SU only ports) for enhanced DMRS type.

[0180] [Table 16]

[0181] <Proposal 2>

[0182] For DMRS types (e.g., legacy DMRS settings below Rel-17), the corresponding DMRS is multiplexed into FD-OCC length 2. For enhanced DMRS types (e.g., enhanced DMRS settings in Rel-18), the corresponding DMRS is multiplexed into FD-OCC length 4. For enhanced DMRS types, the number of orthogonal DMRS ports is doubled compared to existing DMRS types, and the number of ports that can be instructed to SUs or MUs also increases. The new DMRS port table can be designed taking into account the increased ports (maximum number of orthogonal ports per UE).

[0183] For existing DMRS types, the maximum number of orthogonal ports per UE in MU-MIMO (type 1 with 1-symbol DMRS) is 2.

[0184] In the case of the enhance DMRS type, the maximum number of orthogonal ports per UE in MU-MIMO (type 1 with 1-symbol DMRS) can be four, which is twice the maximum number of orthogonal ports of the existing DMRS type.

[0185] For DMRS configuration enhanced type 1, a DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 8-11.

[0186] For DMRS configuration enhanced type 2, a DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 12-15.

[0187] Based on the Legacy DMRS table / new DMRS table, port index {0, 1} with CDM group=1 and port index {0, 1, 2}, {0, 1, 2, 3} can be instructed to the UE.

[0188] [1] In the case of a legacy DMRS table (for example, in the case of DMRS configuration type 1 / 2), the remaining ports excluding the indicated port are not associated with PDSCH transmissions for other UEs.

[0189] [2] In the case of a new DMRS DMRS table (e.g., for DMRS configuration type 1 / 2), the UE may not assume that all remaining orthogonal ports are not associated with PDSCH transmissions to other UEs, or the UE may make no assumptions about all remaining orthogonal ports.

[0190] If port index {0, 1} with CDM group=1 in the new table, MU scheduling is possible when only some of the ports available for transmission within the corresponding CDM group are specified. If index {0, 1, 2} or index {0, 1, 2, 3} in the new table, MU scheduling is possible when the maximum number of orthogonal ports per UE, which is 4, is not exceeded.

[0191] As described above, based on the increased maximum number of orthogonal ports per UE for the enhanced DMRS type, ports defined as existing SU-only ports can be used for MUs. Table 17 illustrates the increased maximum number of orthogonal ports per UE for the enhanced DMRS type.

[0192] [Table 17]

[0193] Referring to Table 17, the maximum number of orthogonal ports per UE for type 1 with 1-symbol DMRS in the enhanced DMRS type has been changed to 4 (for example, for the DMRS type, the maximum number of orthogonal ports per UE for type 1 with 1-symbol DMRS is 2, see Table 15).

[0194] When DMRS ports are multiplexed to FD-OCClength 4 (enhanced DMRS type), MU scheduling is restricted as shown in Table 18 below (i.e., index {0, 1}, index {0, 1, 2}, and index {0, 1, 2, 3} are excluded from SU only ports).

[0195] Table 18 below illustrates MU scheduling restrictions (SU only ports) for the enhanced DMRS type.

[0196] [Table 18]

[0197] For index {0, 2}, the new port table can also indicate one port per CDM group with a single symbol. For SU UEs, there is no descrambling issue for FD-OCC, and channel estimation is performed on a per-RE basis, improving channel estimation accuracy in frequency selective channels. Therefore, even if the per-UE rank restriction for MUs is doubled, the number of legacy and CDM groups does not change, so MU scheduling is restricted as in legacy.

[0198] For index {0, 2, 4, 6}, two ports are assigned to each CDM group using double symbols and scrambled using TD-OCC. For SU UEs, there is no descrambling issue for FD-OCC. Channel estimation is performed on a per-RE basis, and frequency selective channels improve channel estimation accuracy, so MU scheduling is restricted like in Legacy.

[0199] The above example applies to DMRS port indexes corresponding to Cat.1.

[0200] For DMRS port index operations corresponding to Cat.2, an offset of 8 or an offset of 12 can be applied to the above examples (index {0, 1}, index {0, 1, 2}, index {0, 1, 2, 3}).

[0201] For example, for enhanced DMRS type 1, at least one of the indices {8, 9}, {8, 9, 10}, or {8, 9, 10, 11} may be excluded from the SU only ports (MU scheduling restriction).

[0202] For example, for enhanced DMRS type 2, at least one of the indices {12, 13}, {12, 13, 14}, or {12, 13, 14, 15} may be excluded from the SU ONLY PORTS (MU scheduling restriction).

[0203] <Proposal 3>

[0204] According to Cat.1 or Cat.2, ranks 3 & 4 are not designated based on one CDM group. Cat.3 is defined to designate ranks 3 & 4 based on one CDM group. Here, rank can mean the number of layers, and rank can be determined by the number of designated ports (e.g., if 3 ports are designated, rank 3).

[0205] For example, in the case of CDM group 1, Cat.1 indicates 2 ports {0, 1}, and Cat.2 indicates 2 ports {8, 9}. In other words, Cat.1 / 2 indicates rank 2 based on one CDM group.

[0206] Cat. 3 allows the configuration / indication of rank 4 based on one CDM group. Specifically, Cat. 3 can indicate 4 ports {0, 1, 8, 9} based on the number of DMRS CDM group(s) without data=1.

[0207] Also, when number of DMRS CDM group(s) without data=2, four ports {0, 1, 2, 3} in Cat.1 and four ports {8, 9, 10, 11} in Cat.2 allow for rank 4 indication based on two CDM groups, respectively. Cat.3 allows for rank 8 indication based on two CDM groups.

[0208] Specifically, Cat. 3 can specify 4 ports {0, 1, 8, 9} (CDM group 1) + 4 ports {2, 3, 10, 11} (CDM group 2). In other words, Cat. 3 can specify / set rank 8 based on CDM groups 1 & 2.

[0209] However, when the number of DMRS CDM group(s) without data=1 is specified, four ports {0, 1, 8, 9} of Cat.3 are specified, and all ports capable of transmission within the corresponding CDM group are specified, so they are used as SU only.

[0210] In the case of DMRS configuration enhanced type 1, a DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 8-11.

[0211] For DMRS configuration enhanced type 2, a DMRS port table (antenna port table) may be defined to include values ​​based on at least one of indexes 12-15.

[0212] In the new DMRS table, for Cat. 3 DMRS port(s) & number of DMRS CDM group(s) without data=2, the maximum number of orthogonal ports per UE in MU-MIMO for type 1 with 1-symbol DMRS is doubled (2 → 4).

[0213] In the new DMRS table, the following values ​​(e.g., values ​​26 and 27 in Table 13) can be defined: i) port index {0, 1, 8} with number of DMRS CDM group(s) without data=2, ii) port index {0, 1, 8, 9} with number of DMRS CDM group(s) without data=2.

[0214] When i) and / or ii) are indicated to the UE, the UE may assume / operate as follows: The UE may not assume that the remaining ports excluding the indicated ports (i) 0, 1, 8 or i) 0, 1, 8, 9 are not associated with PDSCH transmission for other UEs, or the UE may make no assumptions about the remaining ports excluding the indicated ports. That is, when CDM group = 2, even if index {0, 1, 8} and index {0, 1, 8, 9} are indicated, the indicated ports do not exceed four ports, so MU scheduling is possible.

[0215] Table 19 below illustrates MU scheduling restrictions (SU only ports) for the enhanced DMRS type.

[0216] [Table 19]

[0217] In MU-MIMO, if the maximum number of orthogonal ports for type 1 with 1-symbol DMRS among the maximum number of orthogonal ports per UE does not increase from 2 to 4, MU scheduling will be restricted if three or more ports are indicated based on Cat. 3. In other words, if the number of ports indicated based on Cat. 3 in the new DMRS table exceeds two (e.g., index {0, 1, 8}), MU scheduling for the remaining ports excluding the indicated ports will be restricted.

[0218] <Extended>

[0219] The DMRS port index indicated based on the above DMRS field value (antenna port field value) can be matched to different values ​​in the table.

[0220] At least one combination / combination of Proposals 1 to 3 described above may be applied to the operation of a terminal / base station. As an example, the operation / settings based on Proposals 1 and 2 may be applied to the operation of a terminal / base station.

[0221] Whether the proposal is applied and factors used in the proposal can be configured / instructed by the base station to the UE through DCI / MAC-CE / RRC signaling. For example, the base station can transmit configuration information related to the DMRS to the UE based on RRC signaling. Based on the configuration information, the type related to the DMRS can be determined as DMRS TYPE 1 / 2 or enhanced DMRS TYPE 1 / 2.

[0222] Information regarding whether the proposal is applied and the factors used in the proposal may be reported by the UE to the base station.

[0223] In practical terms, the operation of the base station / terminal according to the above-described embodiments (e.g., operation based on at least one of Proposals 1 to 3) can be processed by the apparatus (e.g., 100, 200) of Figure 5 described later.

[0224] In addition, the operation of the base station / terminal according to the above embodiments (e.g., operation based on at least one of Proposals 1 to 3) may be stored in a memory (e.g., 140, 240 in FIG. 5) in the form of commands / programs (e.g., instructions, executable code) for driving at least one processor (e.g., 110, 210 in FIG. 5).

[0225] A DMRSport table (antenna port table) based on at least one of the above-mentioned proposals 1 to 3 can be based on the following Tables 20 to 27.

[0226] [Table 20]

[0227] Table 21

[0228] Table 22

[0229] JPEG2026506614000029.jpg159148

[0230] Table 23

[0231] JPEG2026506614000031.jpg164150

[0232] Table 24

[0233] JPEG2026506614000033.jpg93149

[0234] Table 25

[0235] JPEG2026506614000035.jpg97149

[0236] Table 26

[0237] JPEG2026506614000037.jpg214150

[0238] JPEG2026506614000038.jpg213148

[0239] JPEG2026506614000039.jpg52147

[0240] [Table 27]

[0241] JPEG2026506614000041.jpg213148

[0242] JPEG2026506614000042.jpg212150

[0243] JPEG2026506614000043.jpg57148

[0244] As an example, operations based on the above Tables 20 to 27 can be based on the following Table 28.

[0245] [Table 28]

[0246] Table 29 below illustrates DMRS type 1 (ports 1007) / enhanced DMRS type 1 (ports 1000-1015).

[0247] [Table 29]

[0248] As an example, the number of CDM groups (Number of DMRS CDM group(s) without data) 1 or 2, which is determined / indicated based on the value of the antenna port field, may correspond to CDM group {0} and CDM group {0, 1}, respectively.

[0249] The following Table 30 illustrates DMRS TYPE2 (ports 1000-1011) / enhanced DMRS TYPE2 (ports (circle 1) 000-1023).

[0250] [Table 30]

[0251] As an example, the number of CDM groups determined / indicated based on the value of the antenna port field (Number of DMRS CDM group(s) without data) 1, 2, or 3 may correspond to CDM group{0}, CDM group{0, 1}, or CDM group{0, 1, 2}, respectively.

[0252] Hereinafter, the above-mentioned embodiment will be described in detail from the viewpoint of the operation of a terminal and a base station with reference to Figures 3 and 4. The methods described below are only divided for the convenience of explanation, and it goes without saying that some components of any one method may be replaced with some components of another method or may be combined with each other and applied.

[0253] FIG. 3 is a flowchart illustrating a method performed by a terminal according to an embodiment of the present specification.

[0254] Referring to FIG. 3, a method performed by a terminal according to one embodiment of the present specification includes a step S310 of receiving configuration information related to a DMRS, a step S320 of receiving DCI for scheduling a PDSCH, a step S330 of receiving a DMRS for a PDSCH, and a step S340 of receiving a PDSCH.

[0255] As mentioned above, in the following description, when PDSCH scheduling for other terminals is restricted, it is defined as a case where one codeword is scheduled for the terminal.

[0256] In S310, the terminal receives configuration information related to a demodulation reference signal (DMRS) from the base station. The configuration information related to the DMRS may be based on the DMRS-DownlinkConfig in Table 1.

[0257] The DMRS configuration based on the configuration information may be based on a DMRS type (DMRS type) or an enhanced DMRS type (enhanced DMRS type).

[0258] Specifically, the DMRS type may be DMRS TYPE 1 or DMRS TYPE 2. The enhanced DMRS type may be enhanced DMRS TYPE 1 or enhanced DMRS type 2.

[0259] For the DMRS TYPE 1, i) antenna ports 1000 to 1003 (for example, single-symbol DMRS) or ii) antenna ports 1000 to 1003 and 1008 to 1011 (for example, double-symbol DMRS) can be supported.

[0260] For the DMRS TYPE 2, i) antenna ports 1000 to 1005 (for example, single-symbol DMRS) or ii) antenna ports 1000 to 1011 (for example, double-symbol DMRS) can be supported.

[0261] For the enhanced DMRS TYPE 1, i) antenna ports 1000 to 1003 and 1008 to 1011 (for example, single-symbol DMRS) or ii) antenna ports 1000 to 1015 (for example, double-symbol DMRS) can be supported.

[0262] For the enhanced DMRS TYPE 2, i) antenna ports 1000 to 1005 and 1012 to 1017 (eg, single-symbol DMRS) or ii) antenna ports 1000 to 1023 (eg, double-symbol DMRS) can be supported.

[0263] That is, the number of antenna ports supported for enhanced DMRS type1 / 2 may be twice the number of antenna ports supported for DMRS type1 / 2 (4, 6, 8, or 12).

[0264] For example, if dmrs-type (type2) is configured by the configuration information, the DMRS configuration may be based on DMRS type2.

[0265] For example, if the configuration information does not configure dmrs-type(type2), the DMRS configuration may be based on DMRS type1.

[0266] For example, if the configuration information sets dmrs-type(type2) and dmrs-TypeEnh(enabled), the DMRS configuration may be based on enhanced DMRS type2.

[0267] For example, if the configuration information does not set dmrs-type(type2) but sets dmrs-TypeEnh(enabled), the DMRS configuration may be based on enhanced DMRS type1.

[0268] At S320, the UE receives downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH) from the base station. The DCI may include an antenna port field.

[0269] The antenna port field may indicate one of the values ​​defined in a table. For example, if the DMRS configuration is the DMRS type 1 / 2, the antenna port field may indicate a value defined in one of the tables (e.g., Tables 1 to 4) based on one of Tables 5 to 12. For example, if the DMRS configuration is the enhanced DMRS type 1 / 2, the antenna port field may indicate a value defined in one of the tables (e.g., Tables 5 to 8, Tables 20 to 27) defined based on at least one of Proposal 1 to Proposal 3.

[0270] Each of the values ​​defined by the table may be associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port.

[0271] Two of the values ​​defined in the table can be associated with one CDM group and antenna ports 1000 and 1001. In this case, whether or not the PDSCH scheduling restriction for other terminals is applicable may vary depending on whether the DMRS configuration is a DMRS type or an enhanced DMRS type. This will be described in detail below.

[0272] As an example, if the DMRS configuration is based on the DMRS type and the value indicated based on the antenna port field is 2, the remaining orthogonal antenna ports may not be associated with PDSCH transmission to other terminals.

[0273] As an example, based on the DMRS configuration being based on the enhanced DMRS type and the value indicated based on the antenna port field being 2, the remaining orthogonal antenna ports based on the same CDM group can be associated with PDSCH transmission for other terminals configured with the enhanced DMRS type.

[0274] According to one embodiment, the table may be a table determined based on i) the DMRS configuration and ii) the maximum number of symbols associated with the DMRS (e.g., the maximum number of OFDM symbols indicated by the max-length parameter of the configuration information) from among a plurality of tables.

[0275] The plurality of tables may include i) a first table, a second table, a third table, and a fourth table associated with the DMRS type, and ii) a fifth table, a sixth table, a seventh table, and an eighth table associated with the enhanced DMRS TYPE.

[0276] The first table may be for the DMRS type 1, max-length 1 (e.g., Table 5 or Table 6). The second table may be for the DMRS type 1, max-length 2 (e.g., Table 7 or Table 8). The third table may be for the DMRS type 2, max-length 1 (e.g., Table 9 or Table 10). The fourth table may be for the DMRS type 2, max-length 2 (e.g., Table 11 or Table 12).

[0277] The fifth table may be for the enhanced DMRS type 1, max-length 1 (e.g., Table 13, Table 20, or Table 21). The sixth table may be for the enhanced DMRS type 1, max-length 2 (e.g., Table 22 or Table 23). The seventh table may be for the enhanced DMRS type 2, max-length 1 (e.g., Table 24 or Table 25). The eighth table may be for the enhanced DMRS type 2, max-length 2 (e.g., Table 26 or Table 27).

[0278] As an example, the table may be determined as the first table (e.g., Table 5) based on the DMRS configuration being DMRS type 1 and the maximum number being 1. The table may be determined as the fifth table (e.g., Table 13, Table 20) based on the DMRS configuration being enhanced DMRS type 1 and the maximum number being 1.

[0279] The fifth table may include i) first values ​​defined in the first table, and ii) second values. Each of the first values ​​(e.g., values ​​0-8 in Table 5) may be associated with at least one of antenna ports 1000-1003. Each of the second values ​​(e.g., values ​​12-20 in Table 13) may be associated with at least one of antenna ports 1008-1011. That is, each second value may be associated with an index obtained by adding 8 to the antenna port index indicated by the first value. For example, if a first value is associated with port index x, the second value corresponding to the corresponding first value may be associated with port index x+8.

[0280] A particular one of the first values ​​may be associated with one CDM group and antenna port 1000, 1001. A particular one of the second values ​​may be associated with one CDM group and antenna port 1008, 1009.

[0281] According to one embodiment, the DMRS configuration is based on the enhanced DMRS type 1, and the value indicated based on the antenna port field is the specific second value:

[0282] The remaining orthogonal antenna ports based on the same CDM group may be associated with PDSCH transmission to other terminals configured with enhanced DMRS type 1. That is, based on Proposal 1 and Proposal 2, MU scheduling restrictions are not applied to a first value (e.g., 2 in Cat. 1). In this case, MU scheduling restrictions may also not be applied to a second value (e.g., 14 in Cat. 2) corresponding to the first value.

[0283] According to an embodiment, the fifth table may further include a third value associated with three or more antenna ports among antenna ports 1000 to 1011. When the DMRS configuration is based on the enhanced DMRS type 1, the value indicated based on the antenna port field is the specific third value:

[0284] The remaining orthogonal antenna ports may not be associated with PDSCH transmissions to other terminals. This embodiment may be based on Proposal 3.

[0285] At S330, the terminal receives the DMRS for the PDSCH from the base station.

[0286] In S340, the terminal receives the PDSCH from the base station.

[0287] The operations based on S310 to S340 described above can be realized by the device of Fig. 5. For example, the terminal 200 can control one or more transceivers 230 and / or one or more memories 240 to perform the operations based on S310 to S340.

[0288] In the method, some steps may be omitted or added. For example, the operation according to S340 may be omitted in the method.

[0289] The above-described embodiment will now be described in detail from the perspective of the operation of the base station.

[0290] S410 to S440 described below correspond to S310 to S340 described in FIG. 3. In consideration of this correspondence, duplicated descriptions will be omitted. That is, specific descriptions of base station operations described below can be replaced with the descriptions / embodiments of FIG. 3 corresponding to the operations. As an example, the descriptions / embodiments of S310 to S340 in FIG. 3 can also be applied to the base station operations of S410 to S440 described below.

[0291] FIG. 4 is a flowchart illustrating a method performed by a base station according to another embodiment of the present disclosure.

[0292] Referring to FIG. 4, a method performed by a base station according to another embodiment of the present specification includes a step of transmitting configuration information related to a DMRS (S410), a step of transmitting DCI for scheduling a PDSCH (S420), a step of transmitting a DMRS for a PDSCH (S430), and a step of transmitting a PDSCH (S440).

[0293] At S410, the base station transmits configuration information related to a demodulation reference signal (DMRS) to the terminal.

[0294] In S420, the base station transmits downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH) to the terminal.

[0295] At S430, the base station transmits the DMRS for the PDSCH to the terminal.

[0296] At S440, the base station transmits the PDSCH to the terminal.

[0297] The operations based on S410 to S440 described above can be realized by the device of Fig. 5. For example, the base station 100 can control one or more transceivers 130 and / or one or more memories 140 to perform the operations based on S410 to S440.

[0298] Some steps may be omitted or added in the method, for example, the operation according to S440 may be omitted in the method.

[0299] An apparatus to which the embodiments of the present specification can be applied (an apparatus that implements the methods / operations according to the embodiments of the present specification) will be described below with reference to FIG.

[0300] FIG. 5 is a diagram showing the configurations of the first device and the second device according to the embodiment of the present specification.

[0301] The first device 100 may include a processor 110 , an antenna unit 120 , a transceiver 130 , and a memory 140 .

[0302] The processor 110 performs baseband-related signal processing and may include an upper layer processing unit 111 and a physical layer processing unit 115. The upper layer processing unit 111 may process operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit 115 may process operations of the PHY layer. For example, if the first device 100 is a base station device in base station-terminal communication, the physical layer processing unit 115 may perform uplink reception signal processing, downlink transmission signal processing, etc. For example, if the first device 100 is a first terminal device in terminal-terminal communication, the physical layer processing unit 115 may perform downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc. In addition to performing baseband-related signal processing, the processor 110 may control the overall operation of the first device 100.

[0303] The antenna unit 120 may include one or more physical antennas, and when multiple antennas are included, it may support MIMO transmission and reception. The transceiver 130 may include an RF (Radio Frequency) transmitter and an RF receiver. The memory 140 may store information processed by the processor 110, software related to the operation of the first device 100, an operating system, applications, etc., and may also include components such as buffers.

[0304] The processor 110 of the first device 100 may be configured to implement the operation of a base station in base station-terminal communication (or the operation of a first terminal device in terminal-terminal communication) in the embodiments described in this disclosure.

[0305] The second device 200 may include a processor 210 , an antenna unit 220 , a transceiver 230 , and a memory 240 .

[0306] The processor 210 performs baseband-related signal processing and may include an upper layer processing unit 211 and a physical layer processing unit 215. The upper layer processing unit 211 may process operations of the MAC layer, the RRC layer, or higher layers. The physical layer processing unit 215 may process operations of the PHY layer. For example, when the second device 200 is a terminal device in base station-terminal communication, the physical layer processing unit 215 may perform downlink reception signal processing, uplink transmission signal processing, etc. For example, when the second device 200 is a second terminal device in terminal-terminal communication, the physical layer processing unit 215 may perform downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc. In addition to performing baseband-related signal processing, the processor 210 may control the overall operation of the second device 210.

[0307] The antenna unit 220 may include one or more physical antennas, and when multiple antennas are included, it may support MIMO transmission and reception. The transceiver 230 may include an RF transmitter and an RF receiver. The memory 240 may store information processed by the processor 210, as well as software, an operating system, applications, etc. related to the operation of the second device 200, and may also include components such as buffers.

[0308] The processor 210 of the second device 200 may be configured to implement the operation of a terminal in base station-terminal communication (or the operation of a second terminal device in terminal-terminal communication) in embodiments described in this disclosure.

[0309] In the operation of the first device 100 and the second device 200, the matters described in the examples of the present disclosure regarding the base station and terminal in base station-terminal communication (or the first terminal and second terminal in terminal-terminal communication) may be similarly applied, and duplicated explanations will be omitted.

[0310] Here, wireless communication technologies implemented by the devices 100 and 200 of the present disclosure may include LTE, NR, and 6G as well as Narrowband Internet of Things (NB-IoT) for low-power communication. For example, the NB-IoT technology may be an example of a Low Power Wide Area Network (LPWAN) technology, and may be implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the aforementioned names.

[0311] Additionally or alternatively, the wireless communication technology implemented in the devices 100, 200 of the present disclosure may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and may be referred to by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in at least one of various standards such as 1) LTE Cat 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, but is not limited to the aforementioned names.

[0312] Additionally or alternatively, the wireless communication technology implemented in the devices 100, 200 of the present disclosure may include, but is not limited to, at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN), which allow for low-power communication. For example, ZigBee technology may be referred to by various names and may create personal area networks (PANs) related to small / low-power digital communication based on various standards such as IEEE 802.15.4.

[0313] [Claims at the time of international application] [Claim 1] 1. A method performed by a terminal in a wireless communication system, comprising: receiving configuration information related to a Demodulation Reference Signal (DMRS); the DMRS configuration based on the configuration information is based on a DMRS type or an enhanced DMRS type; receiving Downlink Control Information (DCI) for scheduling a Physical Downlink Shared Channel (PDSCH); The DCI includes an antenna port field, receiving the DMRS of the PDSCH; receiving the PDSCH; the antenna port field indicates one of the values ​​defined by a table; each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port; Two of the values ​​defined in the table are associated with one CDM group and antenna ports 1000, 1001; The DMRS configuration is based on the DMRS type, and the value indicated based on the antenna port field is 2. The remaining orthogonal antenna ports are not associated with PDSCH transmissions to other terminals, the DMRS configuration is based on the enhanced DMRS type, and the indicated value based on the antenna port field is 2; The method, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS type. [Claim 2] the DMRS type is DMRS Type 1 or DMRS Type 2; The method of claim 1 , wherein the enhanced DMRS type is an enhanced DMRS type 1 or an enhanced DMRS type 2. [Claim 3] Regarding DMRS Type 1, i) Antenna ports 1000 to 1003, or ii) The method according to claim 2, characterized in that antenna ports 1000 to 1003 and 1008 to 1011 are supported. [Claim 4] Regarding the DMRS Type 2, i) Antenna ports 1000 to 1005, or ii) The method according to claim 2, characterized in that antenna ports 1000 to 1011 are supported. [Claim 5] For the Enhanced DMRS Type 1, i) Antenna ports 1000 to 1003 and 1008 to 1011, or ii) The method according to claim 2, characterized in that antenna ports 1000 to 1015 are supported. [Claim 6] For the Enhanced DMRS Type 2: i) Antenna ports 1000 to 1005 and 1012 to 1017, or ii) The method according to claim 2, characterized in that antenna ports 1000 to 1023 are supported. [Claim 7] The table is one of a plurality of tables. i) the DMRS configuration; and ii) a table determined based on a maximum number of symbols associated with the DMRS. [Claim 8] The plurality of tables include: i) a first table, a second table, a third table, and a fourth table associated with the DMRS type; and ii) a fifth table, a sixth table, a seventh table and an eighth table associated with the improved DMRS TYPE. [Claim 9] determining the table as the first table based on the DMRS configuration being DMRS Type 1 and the maximum number being 1; determining the table as the fifth table based on the DMRS configuration being enhanced DMRS type 1 and the maximum number being 1; The fifth table is i) a first value defined in said first table; and ii) includes a second value; Each of the first values ​​is associated with at least one of the antenna ports 1000 to 1003; 9. The method of claim 8, wherein each of the second values ​​is associated with at least one of the antenna ports 1008-1011. [Claim 10] a particular first value among the first values ​​is associated with one CDM group and antenna port 1000, 1001; 10. The method of claim 9, wherein a particular one of the second values ​​is associated with one CDM group and antenna port 1008, 1009. [Claim 11] based on the DMRS configuration being based on the enhanced DMRS Type 1 and the value indicated based on the antenna port field being a specific second value; 11. The method of claim 10, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS Type 1. [Claim 12] The fifth table further includes a third value associated with three or more antenna ports among the antenna ports 1000 to 1011, 10. The method of claim 9, wherein a particular third value among the third values ​​is associated with one CDM group and antenna ports 1000, 1001, 1008 and 1009. [Claim 13] based on the DMRS configuration being based on the enhanced DMRS Type 1 and the value indicated based on the antenna port field being the specific third value; 13. The method of claim 12, wherein the remaining orthogonal antenna ports are not associated with PDSCH transmission to other terminals. [Claim 14] 1. A terminal operating in a wireless communication system, comprising: one or more transceivers; one or more processors; one or more memories coupled to the one or more processors and configured to store instructions; A terminal characterized in that the instructions, when executed by the one or more processors, configure the one or more processors to perform all steps of the method according to any one of claims 1 to 13. [Claim 15] 1. An apparatus comprising: one or more memories; and one or more processors operatively connected to said one or more memories, An apparatus, characterized in that the one or more memories store instructions that, when executed by the one or more processors, configure the one or more processors to perform all steps of the method described in any one of claims 1 to 13. [Claim 16] one or more non-transitory computer-readable media storing instructions, One or more non-transitory computer-readable media, characterized in that the instructions executable by one or more processors configure the one or more processors to perform all steps of the method of any one of claims 1 to 13. [Claim 17] 1. A method performed by a base station in a wireless communication system, comprising: transmitting configuration information related to a demodulation reference signal (DMRS); the DMRS configuration based on the configuration information is based on a DMRS type or an enhanced DMRS type; transmitting downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH); The DCI includes an antenna port field, transmitting the DMRS for the PDSCH; transmitting the PDSCH; The antenna port field indicates one of the values ​​defined by a table; Each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port; Among the values ​​defined in the table, 2 is associated with one CDM group and antenna ports 1000, 1001; The DMRS configuration is based on the DMRS TYPE, and the value indicated based on the antenna port field is 2. The remaining orthogonal antenna ports are not associated with PDSCH transmissions to other terminals, the DMRS configuration is based on the enhanced DMRS type, and the indicated value based on the antenna port field is 2; The method, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS type. [Claim 18] 1. A base station operating in a wireless communication system, comprising: one or more transceivers; one or more processors; one or more memories coupled to the one or more processors and configured to store instructions; 18. A base station, characterized in that the instructions, when executed by the one or more processors, configure the one or more processors to perform all steps of the method according to claim 17.

Claims

1. 1. A method performed by a terminal in a wireless communication system, comprising: receiving configuration information related to a demodulation reference signal (DMRS); The DMRS configuration based on the configuration information is based on a DMRS type or an enhanced DMRS type; receiving downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH); The DCI includes an antenna port field, receiving the DMRS of the PDSCH; receiving the PDSCH; The antenna port field indicates one of the values ​​defined by a table, Each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port; Two of the values ​​defined in the table are associated with one CDM group and antenna ports 1000, 1001; The DMRS configuration is based on the DMRS type, and the value indicated based on the antenna port field is 2. The remaining orthogonal antenna ports are not associated with PDSCH transmissions to other terminals; The DMRS configuration is based on the enhanced DMRS type, and the indicated value based on the antenna port field is 2; The method, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals to which the improved DMRS type is configured.

2. the DMRS type is DMRS type 1 or DMRS type 2; The method of claim 1 , wherein the enhanced DMRS type is enhanced DMRS type 1 or enhanced DMRS type 2.

3. Regarding DMRS Type 1, i) antenna ports 1000 to 1003, or ii) The method of claim 2, wherein antenna ports 1000 to 1003 and 1008 to 1011 are supported.

4. Regarding the DMRS Type 2, i) antenna ports 1000 to 1005, or ii) The method of claim 2, wherein antenna ports 1000 to 1011 are supported.

5. For the enhanced DMRS Type 1, i) antenna ports 1000-1003 and 1008-1011, or ii) The method of claim 2, wherein antenna ports 1000 to 1015 are supported.

6. For the enhanced DMRS Type 2, i) antenna ports 1000-1005 and 1012-1017, or ii) The method of claim 2, wherein antenna ports 1000 to 1023 are supported.

7. The table is one of a plurality of tables. i) the DMRS configuration; and ii) a table determined based on a maximum number of symbols associated with the DMRS.

8. The plurality of tables include: i) a first table, a second table, a third table, and a fourth table associated with the DMRS type; and 8. The method of claim 7, further comprising: ii) a fifth table, a sixth table, a seventh table, and an eighth table associated with the enhanced DMRS TYPE.

9. The table is determined as the first table based on the DMRS configuration being DMRS Type 1 and the maximum number being 1; The table is determined as the fifth table based on the DMRS configuration being an enhanced DMRS type 1 and the maximum number being 1; The fifth table is i) a first value defined in the first table; and ii) includes a second value; each of the first values ​​is associated with at least one of antenna ports 1000-1003; 9. The method of claim 8, wherein each of the second values ​​is associated with at least one of antenna ports 1008-1011.

10. a particular first value among the first values ​​is associated with one CDM group and antenna port 1000, 1001; 10. The method of claim 9, wherein a particular one of the second values ​​is associated with one CDM group and antenna port 1008, 1009.

11. The DMRS configuration is based on the enhanced DMRS Type 1, and the value indicated based on the antenna port field is a specific second value; The method of claim 10, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals configured with the enhanced DMRS type 1.

12. the fifth table further includes a third value associated with three or more antenna ports among the antenna ports 1000 to 1011; The method of claim 9, wherein a particular third value among the third values ​​is associated with one CDM group and antenna ports 1000, 1001, 1008 and 1009.

13. the DMRS configuration is based on the enhanced DMRS Type 1, and the value indicated based on the antenna port field is the specific third value; The method of claim 12, wherein the remaining orthogonal antenna ports are not associated with PDSCH transmission to other terminals.

14. 1. A terminal operating in a wireless communication system, comprising: one or more transceivers; one or more processors; one or more memories coupled to the one or more processors and configured to store instructions; A terminal characterized in that the instructions, when executed by the one or more processors, configure the one or more processors to perform all steps of the method according to any one of claims 1 to 13.

15. 1. An apparatus comprising: one or more memories; and one or more processors operatively connected to said one or more memories, The one or more memories store instructions that, when executed by the one or more processors, configure the one or more processors to perform all steps of the method of any one of claims 1 to 13.

16. one or more non-transitory computer-readable media storing instructions, One or more non-transitory computer-readable media, characterized in that the instructions executable by one or more processors configure the one or more processors to perform all the steps of the method of any one of claims 1 to 13.

17. 1. A method performed by a base station in a wireless communication system, comprising: transmitting configuration information related to a demodulation reference signal (DMRS); The DMRS configuration based on the configuration information is based on a DMRS type or an enhanced DMRS type; transmitting downlink control information (DCI) for scheduling a physical downlink shared channel (PDSCH); The DCI includes an antenna port field, transmitting the DMRS for the PDSCH; transmitting the PDSCH; The antenna port field indicates one of the values ​​defined by a table, Each of the values ​​defined by the table is associated with a number of Code Division Multiplexing (CDM) groups and at least one antenna port; Of the values ​​defined in the table, 2 is associated with one CDM group and antenna ports 1000, 1001; The DMRS configuration is based on the DMRS TYPE, and the value indicated based on the antenna port field is 2. The remaining orthogonal antenna ports are not associated with PDSCH transmissions to other terminals, The DMRS configuration is based on the enhanced DMRS type, and the indicated value based on the antenna port field is 2; The method, wherein remaining orthogonal antenna ports based on the same CDM group are associated with PDSCH transmission to other terminals to which the improved DMRS type is configured.

18. 1. A base station operating in a wireless communication system, comprising: one or more transceivers; one or more processors; one or more memories coupled to the one or more processors and configured to store instructions; 20. A base station, characterized in that the instructions, upon being executed by the one or more processors, configure the one or more processors to perform all steps of the method according to claim 17.

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