Method for providing DM-RS configuration information in wireless communication system and apparatus therefor

Abstract

The present disclosure relates to a method performed by a user equipment (UE) in a wireless communication system. Specifically, the method comprises the steps of: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS); and receiving the PDSCH from the BS on the basis of port information of a demodulation reference signal (DM-RS) included in the DCI, where the port information of the DM-RS identifies at least one of a DM-RS port included in the first DM-RS port group and a DM-RS port included in the second DM-RS port group, and determining a DM-RS port included in the second DM-RS port group on the basis of the DM-RS port included in the first DM-RS port group and the at least one offset.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system, and more particularly, to a method for providing DM-RS configuration information in a wireless communication system and an apparatus thereof. Background Art

[0002] Wireless communication systems are being widely deployed to provide various types of communication services, such as voice and data. Generally, a wireless communication system is a multiple-access system that is capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple-access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems. Summary of the invention

[0003] Technical issues

[0004] Based on the above discussion, a method and apparatus for providing DM-RS configuration information in a wireless communication system will be proposed hereinafter.

[0005] Those skilled in the art to which the embodiments pertain will appreciate that the objectives that can be achieved using the embodiments are not limited to the above specific descriptions, and the above objectives and other objectives will be more clearly understood from the following detailed description.

[0006] Technical Solution

[0007] In one technical aspect of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system is provided, the method comprising: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS), and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from among DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS port included in the second DM-RS port group is determined based on the DM-RS port included in the first DM-RS port group and at least one offset.

[0008] In another technical aspect of the present disclosure, a user equipment (UE) in a wireless communication system is provided, the UE including at least one transceiver, at least one processor, and at least one computer memory, the computer memory being operably connected to the at least one processor and storing instructions, which when executed enable the at least one processor to perform operations, the operations including: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS) and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0009] In another technical aspect of the present disclosure, a device for processing in a wireless communication system is provided, the device including at least one processor and at least one computer memory, the computer memory being operably connected to the at least one processor and storing instructions, which when executed enable the at least one processor to perform operations for a user equipment (UE), the operations including: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS), and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0010] In another technical aspect of the present disclosure, a computer-readable storage medium is provided, which stores at least one program code, the program code including instructions that, when executed, enable at least one processor to perform operations for a user equipment (UE), the operations including: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS), and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0011] In another technical aspect of the present disclosure, a method performed by a base station (BS) in a wireless communication system is provided, the method including sending downlink control information (DCI) for a physical downlink shared channel (PDSCH) to a user equipment (UE), and sending the PDSCH to the UE based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0012] In a further technical aspect of the present disclosure, a base station (BS) in a wireless communication system is provided, the BS including at least one transceiver, at least one processor and at least one computer memory, the computer memory being operably connected to the at least one processor and storing instructions, which when executed enable the at least one processor to perform operations, the operations including: sending downlink control information (DCI) for a physical downlink shared channel (PDSCH) to a user equipment (UE); and sending the PDSCH to the UE based on port information of a demodulation reference signal (DM-RS) included in the DCI, wherein the port information of the DM-RS identifies at least one DM-RS port from DM-RS ports included in a first DM-RS port group and DM-RS ports included in a second DM-RS port group, and wherein the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0013] Preferably, the minimum value of at least one offset may be zero, the maximum value of at least one offset may be 8 based on the DM-RS type being the first type, and the maximum value of at least one offset may be 12 based on the DM-RS type being the second type.

[0014] Preferably, based on the number of DM-RS ports identified by the DM-RS port information being two or more, the DM-RS port information may include information of an offset associated with each of the two or more DM-RS ports.

[0015] Preferably, DCI schedules a single codeword through PDSCH, and the number of leading (FL) symbols of DM-RS is 2.

[0016] Preferably, the DCI may include information about the number of DM-RS CDM groups without data, and based on the number of leading (FL) symbols of multiple codewords or DM-RSs scheduled by the DCI through the PDSCH being 1, the number of DM-RS CDM groups without data of the DM-RS may be twice the number of DM-RS CDM groups without data included in the DCI.

[0017] The above-mentioned schemes are only some of the examples of the present disclosure, and those skilled in the art can derive and understand various examples reflecting the technical features of the present disclosure from the following detailed description.

[0018] Beneficial Effects

[0019] According to the present disclosure, wireless signal transmission and reception can be efficiently performed in a wireless communication system.

[0020] Those skilled in the art will appreciate that the technical effects that can be achieved using the present disclosure are not limited to the contents specifically described above, and the above and other technical effects that can be achieved by the present disclosure will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are provided together with the detailed description to help understand the embodiments. However, the technical features of the embodiments are not limited to specific drawings, and the features disclosed in each drawing can be combined with each other to form new embodiments. The reference numerals in each drawing represent structural elements.

[0022] Figure 1 Illustrated are physical channels used in a 3rd Generation Partnership Project (3GPP) system as an example of a wireless communication system and a general signal transmission method using the physical channels.

[0023] Figure 2 The radio frame structure is shown.

[0024] Figure 3 A resource grid of time slots is illustrated.

[0025] Figure 4 illustrates an exemplary mapping of physical channels in time slots;

[0026] Figure 5 An exemplary process of transmitting a physical downlink shared channel (PDSCH) and acknowledgement / negative acknowledgement (ACK / NACK) is illustrated.

[0027] Figure 6 An exemplary physical uplink shared channel (PUSCH) transmission procedure is illustrated.

[0028] Figure 7 Examples of DM-RS configuration types are shown.

[0029] Figure 8 is a flowchart illustrating a process of receiving a PDSCH according to the present disclosure.

[0030] Figures 9 to 12 The diagram is applicable to the communication system (1) and wireless device of the present disclosure. DETAILED DESCRIPTION

[0031] The technology described herein can be used in various wireless access systems such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. CDMA can be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as a radio technology such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented as a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS). 3GPP LTE is part of Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE adopts OFDMA for downlink and SC-FDMA for uplink. LTE-A is the evolution of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is the evolution version of 3GPP LTE / LTE-A / LTE-A pro.

[0032] As more and more communication devices require greater communication capacity when sending and receiving signals, there is a demand for improved mobile broadband communications from legacy radio access technologies. Therefore, communication systems that take into account services / UEs that are sensitive to reliability and latency are being discussed. The next generation radio access technology that takes into account enhanced mobile broadband communications, massive machine type communications (MTC), and ultra-reliable and low-latency communications (URLLC) may be referred to as new radio access technologies (RATs) or new radios (NRs).

[0033] Although the present disclosure is mainly described in the context of 3GPP NR for clarity of description, the technical concept of the present disclosure is not limited to 3GPP NR.

[0034] In this specification, the expression "setting" may be replaced with the expression "configuration / configuration", and the two may be used interchangeably. In addition, conditional expressions (e.g., "if ~~", "in the case of ~~", "when ~~", etc.) may be replaced with the expression "based on the ~~" or "under the state / condition of ~~". In addition, the operation or SW / HW configuration of the user equipment (UE) / base station (BS) performed according to the satisfaction of the condition may be inferred / understood. In addition, when the process of the receiving (or transmitting) side can be inferred / understood from the process of the transmitting (or receiving) side in the signal transmission / reception between the wireless communication device (e.g., BS and UE), its description may be omitted. For example, signal determination / generation / encoding / transmission on the transmitting side may be understood as signal monitoring reception / decoding / determination on the receiving side. In addition, when it is said that the UE performs (or does not perform) a specific operation, this may also be interpreted as the meaning that the BS expects / assumes that the UE performs a specific operation (or expects / assumes that the UE does not perform a specific operation) and operates. In addition, when it is said that the BS performs (or does not perform) a specific operation, this can also be interpreted as the meaning that the UE expects / assumes that the BS performs a specific operation (or expects / assumes that the BS does not perform a specific operation) and operates. In addition, the identification and indexing of each part, embodiment, example, option, method, plan, etc. in the following description are for the convenience of description and should not be interpreted as meaning that each part forms an independent disclosure or that each part should be implemented separately. In addition, unless there is an explicitly conflicting / contradictory description when describing each chapter, embodiment, example, option, method, plan, etc., it can be inferred / interpreted that at least some of them can be implemented in combination, or can be implemented by omitting at least some of them.

[0035] In a wireless communication system, a UE receives information from a BS through a downlink (DL) and transmits information to the BS through an uplink (UL). The information transmitted and received by the BS and the UE includes data and various control information, and includes various physical channels according to the type / purpose of the information transmitted and received by the UE and the BS.

[0036] Figure 1 is a diagram illustrating physical channels in a 3GPP NR system and a signal transmission method using the physical channels.

[0037] When powered on or when the UE initially enters a cell, the UE performs an initial cell search involving synchronization with the BS in step S101. For the initial cell search, the UE receives a synchronization signal block (SSB). The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes with the BS and acquires information such as a cell identifier (ID) based on the PSS / SSS. The UE can then receive broadcast information from the cell on the PBCH. At the same time, the UE can check the downlink channel status by receiving a downlink reference signal (DL RS) during the initial cell search.

[0038] After the initial cell search, the UE may acquire more specific system information by receiving a physical downlink control channel (PDCCH) and receiving a physical downlink shared channel (PDSCH) based on information of the PDCCH in step S102 .

[0039] Subsequently, in order to complete the connection with the eNB, the UE may perform a random access procedure with the eNB (S103 to S106). In the random access procedure, the UE may send a preamble on a physical random access channel (PRACH) (S103), and may receive a PDCCH and a random access response (RAR) to the preamble on a PDSCH associated with the PDCCH (S104). The UE may send a physical uplink shared channel (PUSCH) by using the scheduling information in the RAR (S105), and perform a contention resolution procedure including receiving a PDCCH signal and a PDSCH signal corresponding to the PDCCH signal (S106).

[0040] After the above process, the UE may receive PDCCH and / or PDSCH from the eNB (S107), and send a physical uplink shared channel (PUSCH) and / or a physical uplink control channel (PUCCH) to the eNB (S108), which is a general DL and UL signal transmission process. Specifically, the UE receives downlink control information (DCI) on the PDCCH. The control information sent from the UE to the eNB is collectively referred to as uplink control information (UCI). UCI includes hybrid automatic repeat and request acknowledgement / negative acknowledgement (HARQACK / NACK), scheduling request (SR), channel state information (CSI), etc. CSI includes channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), etc. Although UCI is usually sent through PUCCH, it can be sent through PUSCH when control information and business data should be sent at the same time. In addition, UCI can be sent irregularly through PUSCH by request / instruction of the network.

[0041] Figure 2 The structure of the radio frame is shown in the figure. The radio frame can be used for UL transmission and DL transmission in NR. The length of the radio frame is 10ms and can be defined by two 5ms half frames. HF can include five 1ms subframes. The subframe can be divided into one or more time slots, and the number of time slots in the SF can be determined according to the subcarrier spacing (SCS). Each time slot can include 12 or 14 OFDM (A) symbols according to the cyclic prefix (CP). In the case of normal CP (NCP), each time slot can include 14 symbols, and in the case of extended CP (ECP), each time slot can include 12 symbols. Here, the symbol can be an OFDM symbol (or CP-OFDM symbol) or an SC-FDMA symbol (or DFT-s-OFDM symbol).

[0042] Table 1 below lists the number of symbols N per time slot according to SCS configuration μ in the NCP case slot symb , the number of time slots per frame N frame,u slot and the number of time slots per subframe N subframe,u slot .

[0043] [Table 1]

[0044]

[0045] The following Table 2 lists the number of symbols per time slot, the number of time slots per frame, and the number of time slots per subframe according to SCS in the ECP case.

[0046] [Table 2]

[0047]

[0048] The structure of the frame is only an example. The number of subframes, the number of time slots, and the number of symbols in a frame may vary.

[0049] In the NR system, OFDM parameter sets (e.g., SCS) can be configured differently for multiple cells aggregated for one UE. Therefore, the (absolute time) duration of a time resource (e.g., SF, time slot, or TTI) consisting of the same number of symbols (referred to as a time unit (TU) for simplicity) can be configured differently among the aggregated cells. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol).

[0050] Figure 3 An exemplary resource grid for the duration of a time slot is illustrated. A time slot includes a plurality of symbols in the time domain. For example, in the case of normal CP, a time slot includes 14 symbols, and in the case of extended CP, a time slot includes 12 symbols. A carrier includes a plurality of subcarriers in the frequency domain. A resource block (RB) is defined as a plurality of (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) may be defined as a plurality of physical RBs (PRBs) in the frequency domain and corresponds to a parameter set (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., 5) BWPs. Data communication may be performed in active BWPs, and only one BWP may be activated for a UE. Each element of the resource grid may be referred to as a resource element (RE) and is mapped to a composite symbol.

[0051] Figure 4 An example of mapping physical channels in a time slot is shown. PDCCH can be sent in the DL control region, and PDSCH can be sent in the DL data region. PUCCH can be sent in the UL control region, and PUSCH can be sent in the UL data region. GP provides a time gap for switching from transmission mode to reception mode or from reception mode to transmission mode at the BS and UE. Some symbols of the DL to UL switching time point within a subframe can be configured as GP.

[0052] Each physical channel is described in more detail below.

[0053] PDCCH delivers DCI. For example, PDCCH (i.e., DCI) may carry information about the transport format and resource allocation of the DL shared channel (DL-SCH), resource allocation information of the uplink shared channel (UL-SCH), paging information about the paging channel (PCH), system information about the DL-SCH, information about resource allocation of higher layer control messages such as RAR sent on the PDSCH, transmit power control commands, information about activation / release of configured scheduling, etc. DCI includes a cyclic redundancy check (CRC). Depending on the owner or purpose of the PDCCH, the CRC is masked by various identifiers (IDs) (e.g., radio network temporary identifier (RNTI)). For example, if the PDCCH is for a specific UE, the CRC is masked by the UE ID (e.g., cell RNTI (C-RNTI)). If the PDCCH is for a paging message, the CRC is masked by the paging RNTI (P-RNTI). If the PDCCH is for system information (e.g., system information block (SIB)), the CRC is masked by the system information RNTI (SI-RNTI). When the PDCCH is used for RAR, the CRC is masked by the random access RNTI (RA-RNTI).

[0054] Depending on the aggregation level (AL), the PDCCH includes 1, 2, 4, 8 or 16 control channel elements (CCEs). CCE is a logical allocation unit for providing PDCCH with a specific code rate according to the radio channel state. CCE includes six resource element groups (REGs). REG is defined as one OFDM symbol and one (P)RB. PDCCH is transmitted in a control resource set (CORESET). CORESET is defined as a set of REGs with a given parameter set (e.g., SCS, CP length, etc.). Multiple CORESETs for one UE may overlap with each other in the time / frequency domain. CORESET can be configured by system information (e.g., master information block (MIB)) or UE-specific higher layer (e.g., radio resource control (RRC) layer) signaling. Specifically, the number of RBs and the number of OFDM symbols (up to 3) included in the CORESET can be configured by higher layer signaling.

[0055] For PDCCH reception / detection, the UE monitors PDCCH candidates. PDCCH candidates represent the CCEs that the UE should monitor for PDCCH detection. Depending on the AL, each PDCCH candidate is defined as 1, 2, 4, 8 or 16 CCEs. Monitoring includes (blind) decoding of PDCCH candidates. The set of PDCCH candidates monitored by the UE is defined as the PDCCH search space (SS). The SS includes a common search space (CSS) or a UE-specific search space (USS). The UE can acquire DCI by monitoring PDCCH candidates in one or more SSs configured by MIB or higher layer signaling. Each CORESET is associated with one or more SSs, and each SS is associated with one COREST. The SS can be defined based on the following parameters.

[0056] - controlResourceSetId: indicates the CORESET associated with the SS

[0057] - surveillanceSlotPeriodicityAndOffset: indicates the PDCCH monitoring periodicity (in time slots) and the PDCCH monitoring period offset (in time slots)

[0058] - surveillanceSymbolsWithinSlot: indicates the PDCCH monitoring symbols within a slot (e.g., the first symbol of CORESET)

[0059] - nrofCandidates: AL = {1, 2, 4, 8, 16} indicates the number of PDCCH candidates (one of 0, 1, 2, 3, 4, 5, 6 and 8)

[0060] * An occasion (eg, time / frequency resource) in which a PDCCH candidate is to be monitored is defined as a PDCCH (monitoring) occasion. One or more PDCCH (monitoring) occasions may be configured in one time slot.

[0061] Table 3 illustrates the characteristics of each SS type.

[0062] [Table 3]

[0063]

[0064] Table 4 shows the DCI format transmitted on the PDCCH.

[0065] [Table 4]

[0066]

[0067] DCI format 0_0 may be used to schedule TB-based (or TB-level) PUSCH, and DCI format 0_1 ​​may be used to schedule TB-based (or TB-level) PUSCH or code block group (CBG)-based (or CBG-level) PUSCH. DCI format 1_0 may be used to schedule TB-based (or TB-level) PDSCH, and DCI format 1_1 may be used to schedule TB-based (or TB-level) PDSCH or CBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0 / 0_1 may be referred to as UL grant DCI or UL scheduling information, and DCI format 1_0 / 1_1 may be referred to as DL grant DCI or DL ​​scheduling information. DCI format 2_0 is used to deliver dynamic slot format information (e.g., dynamic SFI) to the UE, and DCI format 2_1 may be used to deliver DL preemption information to the UE. DCI format 2_0 and / or DCI format 2_1 may be transmitted to UEs within the group through a group-common PDCCH, which is a PDCCH delivered to UEs defined as a group.

[0068] DCI format 0_0 and DCI format 1_0 may be referred to as fallback DCI formats, while DCI format 0_1 ​​and DCI format 1_1 may be referred to as non-fallback DCI formats. In the fallback DCI format, the DCI size / field configuration remains the same regardless of the UE configuration. In contrast, in the non-fallback DCI format, the DCI size / field configuration varies depending on the UE configuration.

[0069] The PDSCH carries DL data (e.g., DL-SCH transport block (DL-SCH TB)), and modulation schemes such as quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (16 QAM), 64 QAM, 256 QAM, etc. are applied to the PDSCH. The TB is encoded to generate a codeword. The PDSCH can carry up to two codewords. Each codeword can be subjected to scrambling and modulation mapping, and the modulation symbol generated from the codeword can be mapped to one or more layers. Each layer is mapped to a resource together with a demodulation reference signal (DMRS), generated as an OFDM symbol signal, and transmitted through a corresponding antenna port.

[0070] PUCCH carries UCI. UCI includes the following.

[0071] -SR (Scheduling Request): Information used to request UL-SCH resources

[0072] -HARQ (Hybrid Automatic Repeat Request) -ACK (Acknowledgement): A response to a DL data packet (e.g., codeword) on the PDSCH. This indicates whether the DL data packet has been successfully received. One HARQ-ACK bit can be sent in response to a single codeword, and two HARQ-ACK bits can be sent in response to two codewords. HARQ-ACK responses include positive ACK (ACK for short), negative ACK (NACK), DTX, or NACK / DTX. HARQ-ACK is used interchangeably with HARQ ACK / NACK and ACK / NACK.

[0073] -CSI (Channel State Information): Feedback information for DL ​​channels. Multiple-input multiple-output (MIMO) related feedback information includes RI and PMI.

[0074] Table 5 illustrates an example of a PUCCH format. Depending on PUCCH transmission duration, they may be classified into short PUCCH (formats 0 and 2) and long PUCCH (formats 1, 3, and 4).

[0075] [Table 5]

[0076]

[0077] PUCCH format 0 carries up to 2 bits of UCI and is mapped and transmitted based on a sequence. Specifically, the UE transmits one of multiple sequences through the PUCCH of PUCCH format 0 to send specific UCI to the BS. The UE transmits the PUCCH of PUCCH format 0 in the PUCCH resource for the corresponding SR configuration only when transmitting a positive SR.

[0078] PUCCH format 1 carries up to 2 bits of UCI, and the modulation symbol is spread in the time domain with an orthogonal cover code (OCC) (configured differently depending on whether frequency hopping is performed). DMRS is transmitted in symbols that do not carry modulation symbols (ie, transmitted in time division multiplexing (TDM)).

[0079] PUCCH format 2 carries more than two bits of UCI, and the modulation symbols are sent with DMRS in frequency division multiplexing (FDM). DMRS are located in symbol indexes #1, #4, #7, and #10 within a given RB with a density of 1 / 3. Pseudo-noise (PN) sequences are used for DMRS sequences. Frequency hopping can be activated for 2-symbol PUCCH format 2.

[0080] In PUCCH format 3, UEs do not multiplex within the same PRB and deliver UCI with more than two bits. In other words, PUCCH resources of PUCCH format 3 do not include OCC. Modulation symbols are transmitted in TDM together with DMRS.

[0081] PUCCH format 4 supports multiplexing up to four UEs within the same physical RS and carries UCI with more than two bits. In other words, the PUCCH resources of PUCCH format 3 include OCC. The modulation symbols are transmitted in TDM together with the DMRS.

[0082] At least one of the one or more cells configured for the UE may be configured for PUCCH transmission. At least one primary cell may be configured as a cell for PUCCH transmission. Based on at least one cell configured for PUCCH transmission, at least one PUCCH cell group may be configured for the UE, and each PUCCH cell group includes one or more cells. The PUCCH cell group may be referred to as a PUCCH group for short. PUCCH transmission may be configured not only for the primary cell, but also for the SCell, and the primary cell belongs to the primary PUCCH group, while the PUCCH-SCell configured for PUCCH transmission belongs to the secondary PUCCH group. The PUCCH on the primary cell may be used for cells belonging to the primary PUCCH group, and the PUCCH on the PUCCH-SCell may be used for cells belonging to the secondary PUCCH group.

[0083] The PUSCH carries UL data (e.g., UL-SCH TB) and / or UCI, and is transmitted based on a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform or a discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-s-OFDM) waveform. When the PUSCH is transmitted based on the DFT-s-OFDM waveform, the UE transmits the PUSCH by applying transform precoding. For example, when transform precoding is not possible (e.g., transform precoding is disabled), the UE may transmit the PUSCH based on the CP-OFDM waveform, and when transform precoding is possible (e.g., transform precoding is enabled), the UE may transmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDM waveform. PUSCH transmission may be dynamically scheduled by a UL grant in the DCI, or semi-statically scheduled based on higher layer (e.g., RRC) signaling (and / or layer 1 (L1) signaling (e.g., PDCCH)). PUSCH transmission can be performed in a codebook-based or non-codebook-based manner.

[0084] Figure 5 Figure ACK / NACK transmission process. Figure 5 , the UE may detect the PDCCH in slot #n. The PDCCH includes DL scheduling information (e.g., DCI format 1_0 or DCI format 1_1). The PDCCH indicates DL assignment to PDSCH offset K0 and PDSCH to HARQ-ACK report offset K1. For example, DCI format 1_0 or DCI format 1_1 may include the following information.

[0085] - Frequency domain resource assignment: indicates the RB set assigned to the PDSCH.

[0086] - Time domain resource assignment: Indicates K0 (e.g., slot offset), the starting position of PDSCH in slot #n+K0 (e.g., OFDM symbol index), and the length of PDSCH (e.g., number of OFDM symbols)

[0087] -PDSCH to HARQ_feedback timing indicator: indicates K1.

[0088] -HARQ process number (4 bits): Indicates the HARQ process ID used for data (e.g., PDSCH or TB)

[0089] -PUCCH resource indicator (PRI): indicates the PUCCH resource to be used for UCI transmission among multiple PUCCH resources in a PUCCH resource set.

[0090] Subsequently, the UE may receive PDSCH from slot #(n+K0) according to the scheduling information in slot #n. After completing PDSCH reception in slot #n1 (where n+K0≤n1), the UE may send UCI via PUCCH in slot #(n1+K1). UCI may include a HARQ-ACK response to the PDSCH. Figure 5 In the description, for convenience, it is assumed that the SCS for PDSCH and the SCS for PUCCH are the same, and time slot #n1=time slot #n+K0, but the present disclosure is not limited thereto. When the SCSs are different, K1 can be indicated / interpreted based on the SCS of PUCCH.

[0091] When the PDSCH is configured to transmit up to one TB, the HARQ-ACK response may include one bit. When the PDSCH is configured to transmit up to two TBs, the HARQ-ACK response may include two bits if spatial bundling is not configured, and may include one bit if spatial bundling is configured. When the HARQ-ACK transmission time for multiple PDSCHs is specified as slot #(n+K1), the UCI transmitted in slot #(n+K1) includes HARQ-ACK responses for multiple PDSCHs.

[0092] Whether the UE should perform spatial bundling on the HARQ-ACK responses may be configured for each cell group (e.g., via RRC / higher layer signaling). For example, spatial bundling may be configured separately for each HARQ-ACK response sent over the PUCCH and / or each HARQ-ACK response sent over the PUSCH.

[0093] Spatial bundling can be supported when the maximum number of TBs (or codewords) that can be received at one time (or schedulable by one DCI) in the corresponding serving cell is 2 (or greater) (for example, when the higher layer parameter maxNrofCodeWordsScheduledByDCI corresponds to 2 TBs). At the same time, more than 4 layers can be used for 2-TB transmission, and up to 4 layers can be used for 1-TB transmission. Therefore, when spatial bundling is configured for the corresponding cell group, spatial bundling can be performed on the serving cells of the cell group that can schedule more than 4 layers. On the serving cell, a UE that wants to send a HARQ-ACK response through spatial bundling can generate a HARQ-ACK response by performing a bitwise logical AND operation on the A / N bits for multiple TBs.

[0094] For example, assuming that a UE receives a DCI that schedules two TBs and receives the two TBs through a PDSCH based on the DCI, the UE that performs spatial bundling can generate a single A / N bit by performing a logical AND operation on a first A / N bit for a first TB and a second A / N bit for a second TB. As a result, when both the first TB and the second TB are ACK, the UE reports an ACK bit value to the BS, and when any one of the TBs is NACK, the UE reports a NACK bit value to the BS.

[0095] For example, when only one TB is actually scheduled in a serving cell configured to receive two TBs, the UE may generate a single A / N bit by performing a logical AND operation on the A / N bits for one TB and a bit value of 1. As a result, the UE reports the A / N bits for one TB to the BS as is.

[0096] There are multiple parallel DL HARQ processes for DL ​​transmission in the BS / UE. Multiple parallel HARQ processes allow DL transmission to be performed continuously while the BS waits for HARQ feedback on the successful or failed reception of the previous DL transmission. Each HARQ process is associated with a HARQ buffer of the Media Access Control (MAC) layer. Each DL HARQ process manages state variables such as the number of transmissions of the MAC physical data block (PDU) in the buffer, the HARQ feedback for the MAC PDU in the buffer, and the current redundancy version. Each HARQ process is identified by a HARQ process ID.

[0097] Figure 6 An exemplary PUSCH transmission process is shown in FIG. Figure 6 , the UE may detect the PDCCH in time slot #n. The PDCCH may include UL scheduling information (eg, DCI format 0_0 or DCI format 0_1). DCI format 0_0 and DCI format 0_1 ​​may include the following information.

[0098] - Frequency domain resource assignment: indicates the RB set allocated to PUSCH.

[0099] -Time domain resource assignment: Specify the slot offset K2, which indicates the starting position (e.g., symbol index) and length (e.g., number of OFDM symbols) of the PUSCH in the slot. The starting symbol and length of the PUSCH can be indicated by the start and length indicator value (SLIV) or separately.

[0100] Then, the UE may transmit the PUSCH in slot #(n+K2) according to the scheduling information in slot #n. The PUSCH includes the UL-SCH TB.

[0101] QCL (quasi co-located)

[0102] The two antenna ports are quasi-co-located when the channel characteristics of one antenna port can be derived from the channel of another antenna port. Channel properties may include one or more of delay spread, Doppler spread, frequency / Doppler shift, average received power, receive timing / average delay, and spatial RX parameters.

[0103] The UE may be configured with a list of multiple TCI-State configurations via a higher layer parameter PDSCH-Config. Each TCI-State is associated with a QCL configuration parameter between one or two DL RS and the DMRS port of the PDSCH. The QCL may include qcl-Type1 for the first DS RS and qcl-Type2 for the second DL RS. The QCL type may correspond to one of the following types.

[0104] - "QCL-TypeA": {Doppler shift, Doppler spread, average delay, delay spread}

[0105] - "QCL-TypeB": {Doppler shift, Doppler spread}

[0106] - "QCL-TypeC": {Doppler shift, average delay}

[0107] - "QCL-TypeD": {spatial Rx parameters}

[0108] Beam Management (BM)

[0109] BM is a series of procedures for acquiring and maintaining BS (or Transmit and Receive Point (TRP)) beams and / or UE beams that can be used for DL ​​and UL transmission / reception. BM may include the following procedures and terms.

[0110] -Beam measurement: The BS or UE measures the characteristics of the received beamforming signal.

[0111] -Beam determination: The BS or UE selects its transmit (Tx) beam / receive (Rx) beam.

[0112] - Beam scanning: Covering the spatial domain by using Tx beams and / or Rx beams in a predetermined manner during a predetermined time interval.

[0113] -Beam reporting: The UE reports information about the beamformed signal based on beam measurements.

[0114] The BM process may be divided into (1) a DL BM process using SSB or CSI-RS and (2) a UL BM process using a sounding reference signal (SRS). In addition, each BM process may include Tx beam scanning for determining a Tx beam and Rx beam scanning for determining an Rx beam.

[0115] The DL BM process may include: (1) transmission of a beamformed DL RS (eg, CSI-RS or SSB) from the BS and (2) beam reporting from the UE.

[0116] The beam report may include a preferred DL RS ID and a reference signal received power (RSRP) corresponding to the DL RS ID. The DL RS ID may be a SSB resource indicator (SSBRI) or a CSI-RS resource indicator (CRI).

[0117] RS related to MIMO (Multiple Input Multiple Output) operation

[0118] Hereinafter, a DM-RS (Demodulation Reference Signal) among RSs related to a MIMO operation will be described.

[0119] In NR, the characteristic of DM-RS is that it is sent only when necessary to enhance network energy efficiency and ensure forward compatibility. The time domain density of DM-RS can vary depending on the speed or mobility of the UE. That is, the density for DM-RS in the time domain may be increased to facilitate tracking the rapid changes of the radio channel in NR.

[0120] (1) DM-RS reception process

[0121] DM-RS related operations for PDSCH reception are discussed.

[0122] When receiving a PDSCH scheduled by DCI format 1_0 or receiving a PDSCH preceded by a random dedicated higher layer configuration among the DM-RS-AdditionalPosition, maxLength, and DM-RS-Type parameters, the UE assumes that there is no PDSCH in the random symbols carrying the DM-RS except for the PDSCH with an allocation duration of PDSCH mapping type B of 2 symbols, a single symbol pre-DM-RS of configuration type 1 is sent on DM-RS port 1000, and all remaining orthogonal antenna ports are not related to the transmission of PDSCH to another UE. In addition,

[0123] - For PDSCH with mapping type A, the UE assumes DM-RS-Additional Position = "pos2" and depending on the PDSCH duration indicated in the DCI, there are up to 2 additional single-symbol DM-RS in one slot.

[0124] - For PDSCH with an allocation duration of 7 symbols (for normal CP with mapping type B) or 6 symbols (for extended CP), when the pre-DM-RS symbol is located in each of the 1st and 2nd symbols of the PDSCH allocation duration, the UE assumes that there is an additional single-symbol DM-RS in the 5th or 6th symbol. Otherwise, the UE assumes that there is no additional DM-RS symbol. And,

[0125] - For PDSCH with an allocation duration of 4 symbols of mapping type B, the UE assumes that there are no additional DM-RS,

[0126] - For PDSCH with an allocation duration of 2 symbols of mapping type B, the UE assumes that no additional DM-RS is present and the UE assumes that the PDSCH exists within the symbol carrying the DM-RS.

[0127] When a PDSCH scheduled by DCI format 1_1 is received through a PDCCH using a CRC scrambled by C-RNTI, MCS-C-RNTI, or CS (Configuration Scheduling)-RNTI,

[0128] - The UE may be configured with a higher layer parameter DM-RS-Type, and the configured DM-RS configuration type is used to receive PDSCH.

[0129] - The UE may be configured with a maximum number of leading DM-RS symbols for PDSCH via the higher layer parameter maxLength given in DM-RS-DownlinkConfig.

[0130] In the UE, the number of DM-RS ports can be scheduled by the antenna port index of DCI format 1_1.

[0131] Figure 7 An example of DM-RS configuration type is shown. Specifically, Figure 7 (a) shows a type 1 DM-RS, and Figure 7 (b) shows a type 2 DM-RS.

[0132] Type 1 DM-RS has a higher RS ​​density in the frequency domain and supports up to 4 (8) ports for single (double) symbol DM-RS. In addition, Type 1 DM-RS supports length 2 F-CDM and FDM for single symbol DM-RS and length 2 F / T-CDM and FDM for double symbol DM-RS. Type 2 DM-RS supports more DM-RS antenna ports and supports up to 6 (12) ports for single (double) symbol DM-RS.

[0133] For Type 1 DM-RS, if the UE is scheduled with one codeword and the antenna port mapping is assigned an index of {2, 9, 10, 11, or 30}, or if the UE is scheduled with two codewords, the UE may assume that all remaining orthogonal antenna ports are not associated with transmission of PDSCH to another UE.

[0134] For Type 2 DM-RS, if the UE is scheduled with one codeword and the antenna port mapping is assigned with indices of {2, 10, 23}, or if the UE is scheduled with two codewords, the UE may assume that all remaining orthogonal antenna ports are not associated with transmission of PDSCH to another UE.

[0135] (2) DM-RS transmission process

[0136] A DM-RS related operation for PUSCH reception will be described. A DM-RS transmission operation is similar to the DM-RS reception related operation examined above, and the DL-related parameter names may be replaced with UL-related parameter names.

[0137] Indication of Demodulation Reference Signal (DM-RS) configuration

[0138] When the UE receives a PDSCH scheduled by DCI, the UE may be configured with the configuration type of the DM-RS through DM-RS-Type as a higher layer parameter, and the DM-RS type is used to receive the PDSCH. In addition, the UE may be configured with the maximum number of leading (FL) DM-RS symbols for pre-insertion of the PDSCH through a higher layer parameter maxLength.

[0139] In the case of Type 1 DM-RS, if the UE is scheduled with a single codeword and specifies DM-RS antenna ports mapped to indices of {2, 9, 10, 11, or 30}, or if the UE is scheduled with two codewords, the UE assumes that all remaining orthogonal DM-RS antenna ports are not associated with the transmission of PDSCH to another UE.

[0140] Alternatively, in the case of Type 2 DM-RS, if the UE is scheduled with a single codeword and specifies DM-RS antenna ports that are mapped to indices of {2, 10, or 23}, or if the UE is scheduled with two codewords, the UE assumes that all remaining orthogonal DM-RS antenna ports are not associated with PDSCH transmissions to another UE.

[0141] According to the current 3GPP NR standard, for 2 FL (preamble) symbols, Type 1 DM-RS has a total of 8 DM-RS antenna ports from DM-RS antenna port 0 to DM-RS antenna port 7, and a DM-RS antenna port combination consisting of a subset of the 8 DM-RS antenna ports (i.e., DM-RS antenna port 0 to DM-RS antenna port 7) can be indicated through the DM-RS antenna port indicator table / field of the DCI.

[0142] On the other hand, in 3GPP NR standard version 18, a total of 16 DM-RS antenna ports are introduced. Since DM-RS antenna port 8 to DM-RS antenna port 15 are added in addition to DM-RS antenna port 0 to DM-RS antenna port 7, if the existing DM-RS antenna port indicator table / field is used as is, only DM-RS antenna port 0 to DM-RS antenna port 7 can be indicated, resulting in the problem that the added DM-RS antenna ports 8 to 15 cannot be indicated.

[0143] In the present disclosure, if the number of orthogonal DM-RS antenna ports is doubled compared to before, a method of indicating the corresponding DM-RS antenna ports through DCI is proposed.

[0144] Although the proposed scheme described below is described based on the downlink DM-RS antenna port indication, the uplink DM-RS antenna port indication can be indicated in the same manner. However, in the uplink DM-RS antenna port indication, since the DM-RS antenna port indicator table is determined for each rank indicated by the SRS resource indicator (SRI) or the precoding matrix index (PMI), only the DM-RS antenna port indicator value of the corresponding rank in the downlink DM-RS antenna port indicator table proposed in the present disclosure can be configured.

[0145] <Proposal 1>

[0146] In Proposal 1 of the present disclosure, the DM-RS antenna port may be indicated by adding an offset f to a DM-RS antenna port combination of each value defined in the existing DM-RS antenna port indicator table. Although Proposal 1 described below is described based on Type 1 DM-RS, the proposed method may be applied regardless of the DM-RS type.

[0147] The value of "f" may be set differently for each UE by the base station and indicated by RRC / MAC CE / DCI. In addition, in the case of type 1 DM-RS, the value of "f" may be indicated as at least one value in the range of 0 to 8, and in the case of type 2 DM-RS, the value of "f" may be indicated as at least one value in the range of 0 to 12.

[0148] The existing DM-RS indicator table is described by taking an example.

[0149] Table 6 exemplarily shows an existing DM-RS indicator table when the maximum number of leading (FL) DM-RS symbols is 2.

[0150] [Table 6]

[0151]

[0152] When the indication value is 20 (i.e., rank is 2, DM-RS antenna port 0 and DM-RS antenna port 1) through the existing DM-RS indicator table of Table 6, the UE interprets that DM-RS antenna port 0+f and DM-RS antenna port 1+f are indicated. When the offset is set to 0 for UE1, UE1 uses the existing DM-RS indicator table as is and makes the DM-RS antenna port indication a subset of DM-RS antenna port 0 to DM-RS antenna port 7. In other words, when the indication value is 20, UE1 interprets the rank as 2 as is, and DM-RS antenna port 0 and DM-RS antenna port 1 are indicated.

[0153] On the other hand, by setting the offset to 8 for UE 1, the DM-RS antenna port indication is made a subset of DM-RS antenna port 8 to DM-RS antenna port 15. For example, if the indication value is 20, UE 2 adds 8 to each DM-RS antenna port and interprets the rank as 2, and indicates DM-RS antenna port 8 and DM-RS antenna port 9.

[0154] Thus, a UE that has received an indication of an offset set to 0 uses DM-RS antenna ports 0 to 7 for MU (multi-user)-MIMO scheduling, and a UE that has received an indication of an offset set to 8 uses DM-RS antenna ports 8 to 15 for MU-MIMO scheduling. In addition, a UE that has received an indication of an offset set to 0 and a UE that has received an indication of an offset set to may perform MU-MIMO scheduling together. In this case, MU-MIMO scheduling is performed using DM-RS antenna port 0 to DM-RS antenna port 15.

[0155] The DM-RS indicator value to which the offset is applied in the above proposed scheme can be applied only when it is 2 FL symbols and / or when only codeword 0 is enabled. In the case of 1 FL symbol, there are only 4 orthogonal DM-RS antenna ports, and even if the number of DM-RS antenna ports is doubled by introducing a new DM-RS pattern in 3GPP NR standard Release 18, there are 8, which is the same as the number of existing 2 FL symbol DM-RS antenna ports, so it can be considered that there is no reason or benefit to introduce a new DM-RS pattern, and therefore, the application of the offset is unnecessary. When both codeword 0 and codeword 1 are enabled, this is a high rank case from the perspective of each UE (i.e., a single user (SU) perspective), and because MU MIMO is mainly used when the rank of each UE is small, there is little reason and benefit to use the new DM-RS pattern.

[0156] Because a common offset is applied regardless of the value of the DM-RS indicator table in Proposal 1, a UE configured with a type 1 DM-RS offset 0 has indication performed within DM-RS antenna port 0 to DM-RS antenna port 7, and a UE configured with a type 1 DM-RS offset 8 has indication performed within DM-RS antenna port 8 to DM-RS antenna port 15. That is, from the perspective of one UE, some of DM-RS antenna port 0 to DM-RS antenna port 7 and some of DM-RS antenna port 8 to DM-RS antenna port 15 cannot be indicated together. For example, in the case of rank 4, DM-RS antenna port 0, DM-RS antenna port 1, DM-RS antenna port 10, and DM-RS antenna port 11 cannot be indicated.

[0157] To alleviate such problems and indicate DM-RS antenna ports more flexibly, different offsets may be applied to each port or each port set. For example, at rank 4 or higher, the first two DM-RS antenna ports may be increased by offset f1, and the remaining two DM-RS antenna ports may be increased by offset f2. In addition, at rank 4 or lower, DM-RS antenna port indication may be performed by increasing the indicated DM-RS antenna port by offset f.

[0158] For more flexible application, the offset can be set by increasing the first and second DM-RS antenna ports among the indicated DM-RS antenna ports by f1, increasing the third and fourth DM-RS antenna ports by f2, and increasing the fifth and sixth DM-RS antenna ports by f3.

[0159] <Proposal 2>

[0160] Proposal 1 of the present disclosure can be used to increase the length of TD (time domain)-OCC (orthogonal cover code), the length of frequency domain (FD)-OCC, or the number of DM-RS antenna ports through TDM, but is invalid under FDM (i.e., a scheme of increasing the number of DM-RS antenna ports by increasing the number of DM-RS CDM groups). This is because the number of DM-RS CDM groups without data is indicated in the DM-RS indicator table, and the increased number of DM-RS CDM groups is not reflected in the DM-RS indicator table.

[0161] Therefore, Proposal 2 of the present disclosure proposes to double the number of DM-RS CDM groups without data in the DM-RS indicator table for ease of interpretation. That is, if the number of DM-RS CDM groups without data is 1, 2, and 3, they are interpreted as 2, 4, and 6, respectively.

[0162] There are only 3 existing type 2 DM-RS CDM groups, DM-RS CDM group 0 to DM-RS CDM group 2, but if a new DM-RS pattern is created by FDM, there may be a total of 6 DM-RS CDM groups, DM-RS CDM group 0 to DM-RS CDM group 5.

[0163] The existing DM-RS indicator table is described by taking an example.

[0164] Table 7 shows an example of an existing DM-RS indicator table when the maximum number of FL (leading) DM-RS symbols is 2.

[0165] [Table 7]

[0166]

[0167] For example, Proposal 1 is applied only when it is a single codeword case and the number of FL symbols in the above Table 7 is 2. If the number of DM-RS CDM groups without data is 1 to 3, the numbers of DM-RS CDM groups are interpreted as 2, 4, and 6, respectively.

[0168] Specifically, if the number of DM-RS CDM groups is interpreted as 2, DM-RS CDM group 0 and DM-RS CDM group 1 are considered to be indicative, if the number of DM-RS CDM groups is interpreted as 4, DM-RS CDM group 0 to DM-RS CDM group 3 are considered to be indicative, and if the number of DM-RS CDM groups is interpreted as 6, DM-RS CDM group 0 to DM-RS CDM group 5 are considered to be indicative.

[0169] In this case, DM-RS antenna port 0, DM-RS antenna port 1, DM-RS antenna port 6 and DM-RS antenna port 7 are set in DM-RS CDM group 0, and DM-RS antenna port 12, DM-RS antenna port 13, DM-RS antenna port 18 and DM-RS antenna port 19 generated by adding 12 as an offset thereto are set in DM-RS CDM group 1.

[0170] In addition, DM-RS antenna port 2, DM-RS antenna port 3, DM-RS antenna port 8 and DM-RS antenna port 9 are set in DM-RS CDM group 2, and DM-RS antenna port 14, DM-RS antenna port 15, DM-RS antenna port 20 and DM-RS antenna port 21 generated by adding 12 as an offset thereto are set in DM-RS CDM group 3.

[0171] Similarly, DM-RS antenna port 4, DM-RS antenna port 5, DM-RS antenna port 10 and DM-RS antenna port 11 are set in DM-RS CDM group 4, and DM-RS antenna port 16, DM-RS antenna port 17, DM-RS antenna port 22 and DM-RS antenna port 23 generated by adding 12 as an offset thereto are set in DM-RS CDM group 5.

[0172] In addition, for backward compatibility with legacy UEs, the RE combination of DM-RS CDM group 0 and DM-RS CDM group 1 has the same RE position as the existing DM-RS CDM group 0, the RE combination of DM-RS CDM group 2 and DM-RS CDM group 3 has the same RE position as the existing DM-RS CDM group 1, and the RE combination of DM-RS CDM group 4 and DM-RS CDM group 5 should have the same RE position as the existing DM-RS CDM group 2.

[0173] Proposal 2 is applied in Type 1 DM-RS as follows.

[0174] If the number of DM-RS CDM groups without data is 1 or 2, the number of DM-RS CDM groups without data should be interpreted as 2 or 4, respectively.

[0175] For example, in Table 6 above, Proposal 1 is applied only if it is a single codeword case and the number of FL symbols is 2. In addition, if the number of DM-RS CDM groups without data is 1 or 2, the number of DM-RS CDM groups without data should be interpreted as 2 or 4, respectively.

[0176] If the number of DM-RS CDM groups without data is interpreted as 2, DM-RS CDM group 0 and DM-RS CDM group 1 are considered to be indicative, and if the number of DM-RS CDM groups without data is interpreted as 4, DM-RS CDM group 0 to DM-RS CDM group 3 are considered to be indicative.

[0177] DM-RS antenna port 0, DM-RS antenna port 1, DM-RS antenna port 4 and DM-RS antenna port 5 are set in DM-RS CDM group 0, and DM-RS antenna port 8, DM-RS antenna port 9, DM-RS antenna port 12 and DM-RS antenna port 13 generated by adding 8 as an offset thereto are set in DM-RS CDM group 1.

[0178] In addition, DM-RS antenna port 2, DM-RS antenna port 3, DM-RS antenna port 6 and DM-RS antenna port 7 are set in DM-RS CDM group 2, and DM-RS antenna port 10, DM-RS antenna port 11, DM-RS antenna port 14 and DM-RS antenna port 15 generated by adding 8 as an offset thereto are set in DM-RS CDM group 3.

[0179] In addition, for backward compatibility with legacy UEs, the RE combination of DM-RS CDM group 0 and DM-RS CDM group 1 should have the same RE position as the existing DM-RS CDM group 0, and the RE combination of DM-RS CDM group 2 and DM-RS CDM group 3 should have the same RE position as the existing DM-RS CDM group 1.

[0180] The DM-RS antenna port indication method may be ultimately applied through a union / combination of the proposals mentioned in this disclosure.

[0181] Figure 8 is a flowchart illustrating a process of receiving a PDSCH according to the present disclosure.

[0182] refer to Figure 8In step A05, the UE receives downlink control information (DCI) for the PDSCH from the BS. Here, the DCI may include port information of a DM-RS (demodulation reference signal) and information on the number of DM-RS CDM groups having no data.

[0183] Next, in step A10, the UE identifies at least one DM-RS port among the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group by using the port information of the DM-RS included in the DCI. Specifically, the DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

[0184] Preferably, DCI schedules a single codeword through PDSCH and is limited to a case where the number of leading (FL) symbols of a DM-RS is 2, and thus DM-RS ports included in the second DM-RS port group may be determined based on one offset.

[0185] More preferably, the minimum value of at least one offset is 0, and the maximum value of at least one offset is determined based on the type of DM-RS. Specifically, when the type of DM-RS is the first type, the maximum value of at least one offset may be 8, and when the type of DM-RS is the second type, the maximum value of at least one offset may be 12. In addition, when the number of DM-RS ports identified by the port information of the DM-RS is 2 or more, the port information of the DM-RS may include information about the offset corresponding to each of the two or more DM-RS ports.

[0186] Finally, in step A15, the UE receives the PDSCH from the BS based on the identified DM-RS port.

[0187] For reference, when DCI schedules multiple codewords through PDSCH or the number of leading (FL) symbols of DM-RS is 1, the number of DM-RS CDM groups without DM-RS data is interpreted as twice the number of DM-RS CDM groups without data included in DCI.

[0188] Fig. 9 An exemplary communication system to which an embodiment of the present disclosure is applied is illustrated.

[0189] refer to Fig. 9, the communication system 1 applied to the embodiment includes a wireless device, a base station (BS), and a network. In this article, the wireless device refers to a device that uses a radio access technology (RAT) (e.g., 5G new RAT (NR)) or long term evolution (LTE)) to perform communication and may be referred to as a communication / radio / 5G device. The wireless device may include, but is not limited to, a robot 100a, vehicles 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing communication between vehicles. In this article, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of head mounted devices (HMDs), head up displays (HUDs) installed in vehicles, televisions, smart phones, computers, wearable devices, home appliance devices, digital signage, vehicles, robots, etc. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebook computers). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters. For example, a BS and a network may be implemented as wireless devices and a specific wireless device 200a may operate as a BS / network node with respect to other wireless devices.

[0190] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without going through the BS / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0191] Wireless communication / connection 150a, 150b or 150c may be established between wireless devices 100a to 100f / BS 200 or BS 200 / BS 200. In this document, wireless communication / connection such as uplink / downlink communication 150a, sidelink communication 150b (or D2D communication) or inter-BS communication (e.g., relay, integrated access backhaul (IAB)) may be established through various RATs (e.g., 5G NR). The wireless device and the BS / wireless device may send / receive radio signals to each other through wireless communication / connection 150a and 150b. For example, wireless communication / connection 150a and 150b may send / receive signals through various physical channels. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation and resource mapping / demapping) and at least a portion of a resource allocation process may be performed based on various proposals of the embodiments.

[0192] Fig.10 An exemplary wireless device to which the embodiments are applicable is shown.

[0193] refer to Fig.10 , the first wireless device 100 and the second wireless device 200 may transmit radio signals via a plurality of RATs (e.g., LTE and NR). In this document, {the first wireless device 100 and the second wireless device 200} may correspond to Fig. 9 {wireless device 100x and BS 200} and / or {wireless device 100x and wireless device 100x}.

[0194] The first wireless device 100 may include one or more processors 102 and one or more memories 104 and additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flowcharts disclosed in this document. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a radio signal including the first information / signals through the transceiver 106. The processor 102 may receive a radio signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including commands for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, processes, proposals, methods and / or operational flowcharts disclosed in this document. In this article, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and send and / or receive radio signals through one or more antennas 108. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In an embodiment, the wireless device may represent a communication modem / circuit / chip.

[0195] The second wireless device 200 may include one or more processors 202 and one or more memories 204 and additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the description, functions, processes, proposals, methods and / or operational flowcharts disclosed in this document. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 106, and then store the information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including commands for executing part or all of the process controlled by the processor 202 or for executing the description, functions, processes, proposals, methods and / or operational flowcharts disclosed in this document. In this article, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and send and / or receive radio signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In an embodiment, the wireless device may represent a communication modem / circuit / chip.

[0196] In the following, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this document.

[0197] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware and software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 so as to be driven by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, commands, and / or command sets.

[0198] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0199] One or more transceivers 106 and 206 can send user data, control information and / or radio signals / channels mentioned in the method and / or operation flow chart of this document to one or more other devices. One or more transceivers 106 and 206 can receive user data, control information and / or radio signals / channels mentioned in the description, function, process, proposal, method and / or operation flow chart disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 can be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can send user data, control information or radio signals to one or more other devices. One or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can receive user data, control information or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208 and one or more transceivers 106 and 206 may be configured to send and receive user data, control information and / or radio signals / channels mentioned in the description, functions, processes, proposals, methods and / or operation flow charts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels, etc. from RF band signals into baseband signals so as to process received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals into RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0200] Fig.11 Other exemplary wireless devices to which this embodiment is applied are shown. The wireless device may be implemented in various forms according to use cases / services (see Fig. 9 ).

[0201] refer to Fig.11 , the wireless devices 100 and 200 may correspond to Fig.10The wireless devices 100 and 200 may be configured by various elements, components, units / parts and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130 and an additional component 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Fig.10 One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, the transceiver 114 may include Fig.10 The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls the overall operation of the wireless device. For example, the control unit 120 may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit 130. The control unit 120 may send information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface, or store information received from the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface in the memory unit 130.

[0202] The additional component 140 may be configured differently depending on the type of the wireless device. For example, the additional component 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device may be implemented in the form of, but not limited to, a robot ( Fig. 9 100a), vehicles ( Fig. 9 100b-1 and 100b-2), XR devices ( Fig. 9 100c), handheld devices ( Fig. 9 100d), household appliances ( Fig. 9 100e), IoT devices ( Fig. 9 100f), digital broadcasting terminals, hologram equipment, public security equipment, MTC equipment, medical equipment, fintech equipment (or financial equipment), security equipment, climate / environmental equipment, AI servers / equipment ( Fig. 9 400), BS ( Fig. 9 200), network nodes, etc. The wireless device can be used in a mobile or fixed location depending on the use case / service.

[0203] exist Fig.11In the wireless devices 100 and 200, all of the various elements, components, units / parts and / or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface, or at least a part thereof may be connected wirelessly through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected through a wire and the control unit 120 and the first unit (e.g., 130 and 140) may be connected wirelessly through the communication unit 110. Each element, component, unit / part and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit and a memory control processor. As another example, the memory 130 may be configured by a random access memory (RAM), a dynamic RAM (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory and / or a combination thereof.

[0204] Fig.12 An exemplary vehicle or autonomous vehicle to which the embodiments are applied is shown. The vehicle or autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0205] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0206] One or more transceivers 106 and 206 can send user data, control information and / or radio signals / channels mentioned in the method and / or operation flow chart of this document to one or more other devices. One or more transceivers 106 and 206 can receive user data, control information and / or radio signals / channels mentioned in the description, function, process, proposal, method and / or operation flow chart disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 can be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can send user data, control information or radio signals to one or more other devices. One or more processors 102 and 202 can perform control so that one or more transceivers 106 and 206 can receive user data, control information or radio signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208 and one or more transceivers 106 and 206 may be configured to send and receive user data, control information and / or radio signals / channels mentioned in the description, functions, processes, proposals, methods and / or operation flow charts disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels, etc. from RF band signals into baseband signals so as to process received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals into RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0207] Fig.11 Other exemplary wireless devices for which embodiments are applied are illustrated. The wireless device may be implemented in various forms depending on the use case / service (see Fig. 9 ).

[0208] refer to Fig.11 , the wireless devices 100 and 200 may correspond to Fig.10The wireless devices 100 and 200 may be configured by various elements, components, units / parts and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130 and an additional component 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Fig.10 One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, the transceiver 114 may include Fig.10 The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 140 and controls the overall operation of the wireless device. For example, the control unit 120 may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit 130. The control unit 120 may send information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface, or store information received from the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface in the memory unit 130.

[0209] The additional component 140 may be configured differently depending on the type of the wireless device. For example, the additional component 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device may be implemented in the form of, but not limited to, a robot ( Fig. 9 100a), vehicles ( Fig. 9 100b-1 and 100b-2), XR devices ( Fig. 9 100c), handheld devices ( Fig. 9 100d), household appliances ( Fig. 9 100e), IoT devices ( Fig. 9 100f), digital broadcasting terminals, hologram equipment, public security equipment, MTC equipment, medical equipment, fintech equipment (or financial equipment), security equipment, climate / environmental equipment, AI servers / equipment ( Fig. 9 400), BS ( Fig. 9 200), network nodes, etc. The wireless device can be used in a mobile or fixed location depending on the use case / service.

[0210] exist Fig.11In the wireless devices 100 and 200, all of the various elements, components, units / parts and / or modules in the wireless devices 100 and 200 may be connected to each other through a wired interface, or at least a part thereof may be connected wirelessly through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be connected through a line and the control unit 120 and the first unit (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. Each element, component, unit / part and / or module within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a set of one or more processors. As an example, the control unit 120 may be configured by a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit and a memory control processor. As another example, the memory 130 may be configured by a random access memory (RAM), a dynamic RAM (DRAM), a read-only memory (ROM), a flash memory, a volatile memory, a non-volatile memory and / or a combination thereof.

[0211] Fig.12 An exemplary vehicle or autonomous vehicle to which the embodiments are applied is shown. The vehicle or autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0212] refer to Fig.12 , the vehicle or autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a drive unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110 / 130 / 140a to 140d correspond to Fig.11 Block 110 / 130 / 140.

[0213] The communication unit 110 may transmit and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 may perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 may include an electronic control unit (ECU). The drive unit 140a may enable the vehicle or autonomous driving vehicle 100 to drive on a road. The drive unit 140a may include an engine, a motor, a power train, wheels, brakes, a steering device, and the like. The power supply unit 140b may supply power to the vehicle or autonomous driving vehicle 100 and include a wired / wireless charging circuit, a battery, and the like. The sensor unit 140c may acquire vehicle status, surrounding environment information, user information, and the like. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, a light sensor, a pedal position sensor, etc. The autonomous driving unit 140d may implement a technology for maintaining a lane on which the vehicle is driving, a technology for automatically adjusting a speed (such as adaptive cruise control), a technology for autonomously driving along a determined path, a technology for driving by automatically setting a path with a destination set, and the like.

[0214] For example, the communication unit 110 may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving path and a driving plan from the obtained data. The control unit 120 may control the drive unit 140a so that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving path according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 may aperiodically / periodically obtain the latest traffic information data from an external server and obtain surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain vehicle status and / or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving path and driving plan based on the retrieved data / information. The communication unit 110 may transfer information about the vehicle position, autonomous driving path, and / or driving plan to an external server. The external server may predict traffic information data based on information collected from the vehicle or autonomous driving vehicle using AI technology, etc., and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0215] Those skilled in the art will appreciate that, without departing from the spirit and basic characteristics of the embodiments, the embodiments can be implemented in other specific ways than those described herein. Therefore, the above-described embodiments should be interpreted as illustrative and not restrictive in all aspects. The scope of the present disclosure should be determined by the attached claims and their legal equivalents, rather than by the above description, and it is intended that all changes falling within the meaning and equivalent range of the attached claims are included therein. It is obvious to those skilled in the art that claims that are not explicitly referenced to each other in the attached claims can be presented in combination as embodiments, or included as new claims by subsequent amendments after filing an application.

[0216] It will be apparent to those skilled in the art that the present disclosure can be implemented in other specific forms without departing from the scope of the present disclosure. Therefore, the above detailed description should not be interpreted as being restrictive in all aspects, but should be regarded as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the attached claims, and all changes within the equivalent range of the present disclosure are intended to be included in the scope of the present disclosure.

[0217] Industrial Applicability

[0218] The present disclosure is applicable to UE, BS or other devices in a wireless mobile communication system.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS); as well as receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

2. The method according to claim 1, wherein the minimum value of the at least one offset is zero, wherein the type based on the DM-RS is a first type, the maximum value of the at least one offset is 8, and wherein the type based on the DM-RS is a second type, the maximum value of the at least one offset is 12.

3. The method according to claim 1, wherein based on the number of the DM-RS ports identified by the port information of the DM-RS being two or more, the port information of the DM-RS includes information about an offset associated with each of the two or more DM-RS ports. The method according to claim 1 , wherein the DCI schedules a single codeword through the PDSCH, and wherein the number of leading (FL) symbols of the DM-RS is 2.

5. The method according to claim 1, wherein the DCI includes information about the number of DM-RS CDM groups without data, and wherein based on the number of leading (FL) symbols of the DM-RS scheduled by the DCI through the PDSCH or the plurality of codewords is 1, the number of the DM-RS CDM groups without data of the DM-RS is twice the number of the DM-RS CDM groups without data included in the DCI.

6. A user equipment (UE) in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, enable the at least one processor to perform operations comprising: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS); and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

7. The UE according to claim 1, wherein the minimum value of the at least one offset is zero, wherein the type based on the DM-RS is a first type, the maximum value of the at least one offset is 8, and wherein the type based on the DM-RS is a second type, the maximum value of the at least one offset is 12.

8. The UE according to claim 1, wherein based on the number of the DM-RS ports identified by the port information of the DM-RS being two or more, the port information of the DM-RS includes information about an offset associated with each of the two or more DM-RS ports. 9 . The UE of claim 1 , wherein the DCI schedules a single codeword through the PDSCH, and wherein the number of leading (FL) symbols of the DM-RS is 2.

10. The UE according to claim 1, wherein the DCI includes information about the number of DM-RS CDM groups without data, and wherein based on the number of leading (FL) symbols of the DM-RS scheduled by the DCI through the PDSCH or the DM-RS being 1, the number of the DM-RS CDM groups without data of the DM-RS is twice the number of the DM-RS CDM groups without data included in the DCI.

11. An apparatus for processing in a wireless communication system, the apparatus comprising: at least one processor; as well as at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, enable the at least one processor to perform operations for a user equipment (UE), the operations comprising: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS); and receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

12. A computer-readable storage medium storing at least one program code, the program code comprising instructions that, when executed, enable at least one processor to perform operations for a user equipment (UE), the operations comprising: receiving downlink control information (DCI) for a physical downlink shared channel (PDSCH) from a base station (BS); as well as receiving the PDSCH from the BS based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

13. A method performed by a base station (BS) in a wireless communication system, the method comprising: Sending downlink control information (DCI) for the physical downlink shared channel (PDSCH) to the user equipment (UE); as well as sending the PDSCH to the UE based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

14. The method of claim 13, wherein a minimum value of the at least one offset is zero, wherein a maximum value of the at least one offset based on the type of the DM-RS is a first type is 8, and wherein a maximum value of the at least one offset based on the type of the DM-RS is a second type is 12.

15. The method according to claim 13, wherein based on the number of the DM-RS ports identified by the DM-RS port information being two or more, the DM-RS port information includes information about an offset associated with each of the two or more DM-RS ports. 16 . The method of claim 13 , wherein the DCI schedules a single codeword through the PDSCH, and wherein the number of leading (FL) symbols of the DM-RS is 2.

17. The method according to claim 13, wherein the DCI includes information about the number of DM-RS CDM groups without data, and wherein based on the number of leading (FL) symbols of the DM-RS scheduled by the DCI through the PDSCH or the DM-RS being 1, the number of the DM-RS CDM groups without data of the DM-RS is twice the number of the DM-RS CDM groups without data included in the DCI.

18. A base station (BS) in a wireless communication system, the BS comprising: at least one transceiver; at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, enable the at least one processor to perform operations comprising: sending downlink control information (DCI) for a physical downlink shared channel (PDSCH) to a user equipment (UE); and sending the PDSCH to the UE based on port information of a demodulation reference signal (DM-RS) included in the DCI, The DM-RS port information identifies at least one DM-RS port from the DM-RS ports included in the first DM-RS port group and the DM-RS ports included in the second DM-RS port group, and The DM-RS ports included in the second DM-RS port group are determined based on the DM-RS ports included in the first DM-RS port group and at least one offset.

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