Method and apparatus for transmitting and receiving downlink reference signal in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. According to one embodiment, a method performed by a terminal (user equipment) in a wireless communication system can include receiving, from a base station, at least one of downlink control information (DCI) including demodulation reference signal (DMRS) allocation information, scheduling information, and a medium access control (MAC) control element (CE); identifying, based on the DMRS allocation information, a DMRS port allocated to a data signal and a DMRS for a physical downlink shared channel (PDSCH); receiving the data signal and the DMRS based on the identified DMRS port; and demodulating the PDSCH based on the DMRS and the data signal. Various other embodiments identified by the specification are possible.

Description

Technical Field

[0001] This disclosure relates to wireless communication systems, and more specifically, to methods and apparatus for transmitting / receiving downlink reference signals in wireless communication systems. Background Technology

[0002] Given the evolution of wireless communication technologies, these technologies have primarily been developed for human-centric services such as voice calls, multimedia services, and data services. With the commercialization of 5G (fifth-generation) communication systems, the number of connected devices is expected to grow exponentially. These will increasingly connect to communication networks. Examples of connected things can include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve in various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. Efforts are underway to develop improved 6G communication systems to provide a wide range of services by connecting hundreds of billions of devices and things in the 6G (sixth-generation) era. For these reasons, 6G communication systems are referred to as "beyond 5G" systems.

[0003] The 6G communication system, which is expected to be commercialized around 2030, will have a peak data rate of trillions (1,000 gigabits) of bits per second (bps) and a radio latency of less than 100 microseconds. Therefore, it will be 50 times that of the 5G communication system and have 1 / 10 of its radio latency.

[0004] To achieve such high data rates and ultra-low latency, 6G communication systems have been considered for implementation in the terahertz (THz) band (e.g., the 95 GHz to 3 THz band). It is anticipated that technologies capable of ensuring signal transmission distance (i.e., coverage) will become even more critical due to the more severe path loss and atmospheric absorption in the terahertz band compared to the millimeter-wave band introduced in 5G. As key technologies for ensuring coverage, it is necessary to develop radio frequency (RF) components, antennas, and novel waveforms with better coverage than orthogonal frequency division multiplexing (OFDM), beamforming and massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, and multi-antenna transmission technologies such as massive MIMO. Furthermore, new technologies for improving the coverage of terahertz band signals have been discussed, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable smart surfaces (RIS).

[0005] Furthermore, to improve spectrum efficiency and overall network performance, the following technologies have been developed for 6G communication systems: full-duplex technology to enable uplink and downlink transmissions to use the same frequency resources simultaneously; network technologies to utilize satellites, high-altitude platform stations (HAPS), etc., in an integrated manner; improved network architectures to support mobile base stations and achieve network operation optimization and automation; dynamic spectrum sharing technology to avoid conflicts through predictions based on spectrum usage; the use of artificial intelligence (AI) in wireless communication, improving overall network operation by leveraging AI in the design phase to develop 6G and internalizing end-to-end AI support functions; and next-generation distributed computing technologies to overcome the limitations of UE computing capabilities through ultra-high-performance communication and computing resources accessible on the network, such as mobile edge computing (MEC), cloud, etc. In addition, efforts are ongoing to enhance connectivity between devices, optimize networks, promote the software-defined networking of network entities, and increase the openness of wireless communication by designing new protocols for use in 6G communication systems, developing mechanisms for achieving hardware-based secure environments and secure data usage, developing technologies for maintaining privacy, and improving network connectivity, software-defined networking of network entities.

[0006] Research and development of 6G communication systems in hyper-connectivity (including human-to-machine (P2M) and machine-to-machine (M2M)) is expected to enable the next hyper-connected experience. Specifically, services such as truly immersive extended reality (XR), high-fidelity mobile holograms, and digital replicas are anticipated to be available through 6G communication systems. Additionally, services such as remote surgery, industrial automation, and emergency response for enhanced security and reliability will be provided through 6G communication systems, enabling these technologies to be applied in various fields such as industry, healthcare, automotive, and home appliances. Summary of the Invention

[0007] Technical issues

[0008] Based on the discussion above, this disclosure will provide an apparatus and method for efficiently transmitting / receiving downlink reference signals in a wireless communication system.

[0009] More specifically, this disclosure provides an apparatus and method for reducing the overhead of downlink reference signal transmission.

[0010] Solution to the problem

[0011] According to the embodiments disclosed herein, a method performed by a user equipment in a wireless communication system may include: receiving from a base station at least one of downlink control information (DCI) including demodulation reference signal (DMRS) allocation information and scheduling information, and media access control (MAC) control element (CE); identifying a data signal for a physical downlink shared channel (PDSCH) and a DMRS port allocated to the DMRS based on the DMRS allocation information; receiving the data signal and the DMRS based on the identified DMRS port; and demodulating the PDSCH based on the DMRS and the data signal.

[0012] According to embodiments of the present disclosure, a user equipment in a wireless communication system may include a transceiver and a controller coupled to the transceiver, wherein the controller is configured to receive from a base station at least one of downlink control information (DCI) including demodulation reference signal (DMRS) allocation information, scheduling information, and media access control (MAC) control element (CE); identify a data signal for a physical downlink shared channel (PDSCH) and a DMRS port allocated to the DMRS based on the DMRS allocation information; receive the data signal and the DMRS based on the identified DMRS port; and demodulate the PDSCH based on the DMRS and the data signal.

[0013] According to embodiments disclosed herein, a method performed by a base station in a wireless communication system may include: identifying a DMRS port that transmits data signals but does not transmit a demodulation reference signal (DMRS); and sending at least one of downlink control information (DCI) and media access control (MAC) control element (CE) to a user equipment, including demodulation reference signal (DMRS) allocation information, scheduling information, wherein the user equipment uses the DMRS allocation information to identify data signals for the physical downlink shared channel (PDSCH) and DMRS ports allocated to the DMRS.

[0014] According to embodiments disclosed herein, a base station in a wireless communication system may include a transceiver and a controller coupled to the transceiver, wherein the controller is configured to identify DMRS ports that do not transmit demodulation reference signals (DMRS) but transmit data signals, and to send at least one of downlink control information (DCI) and media access control (MAC) control element (CE) to a user equipment, including demodulation reference signal (DMRS) allocation information and scheduling information, wherein the user equipment uses the DMRS allocation information to identify data signals for the physical downlink shared channel (PDSCH) and DMRS ports allocated to the DMRS. Attached Figure Description

[0015] Figure 1 An example of a radio resource area in a wireless communication system according to an embodiment of the present disclosure is shown.

[0016] Figure 2 The resource structure in the case of switching the demodulation reference signal (DMRS) port according to an embodiment of the present disclosure is shown.

[0017] Figure 3 An example of DMRS port switching according to an embodiment of the present disclosure is shown.

[0018] Figure 4 An example is shown of a base station sending a signal including a DMRS null indicator to a UE in the event of a DMRS port handover, according to an embodiment of the present disclosure.

[0019] Figure 5 The resource structure in the case of DMRS port switching according to an embodiment of the present disclosure is shown.

[0020] Figure 6 An example is shown of a base station sending a signal to a UE including an inactive DMRS field value and an active DMRS field value during a DMRS port handover in a time slot, according to an embodiment of this disclosure.

[0021] Figure 7 An example is shown of a base station sending a signal including an interference reuse field to a UE in the case of a DMRS port handover in a time slot, according to an embodiment of the present disclosure.

[0022] Figure 8 An example is shown of a base station sending a DMRS port switching mode to a UE in the case of a DMRS port switching in a super time slot according to an embodiment of the present disclosure.

[0023] Figure 9 An example is shown of a base station sending a DMRS port switching mode to a UE in the case of a DMRS port switching in a super time slot according to an embodiment of the present disclosure.

[0024] Figure 10 An example is shown of a base station sending a signal to a UE including a DMRS port switching mode and an inactive DMRS field during a DMRS port handover in a super time slot, according to an embodiment of this disclosure.

[0025] Figure 11 The operation of the base station and UE in the event of a DMRS port handover is illustrated according to an embodiment of the present disclosure.

[0026] Figure 12 Operation of a UE according to an embodiment of this disclosure is illustrated.

[0027] Figure 13 The operation of a base station according to an embodiment of the present disclosure is illustrated.

[0028] Figure 14 The structure of a UE according to an embodiment of the present disclosure is shown.

[0029] Figure 15 The structure of a base station according to an embodiment of the present disclosure is shown.

[0030] Regarding the description of the accompanying drawings, the same or similar reference numerals may be used to refer to the same or similar elements. Detailed Implementation

[0031] The various aspects of the claimed subject matter will now be described with reference to the accompanying drawings, wherein the same reference numerals are used throughout to refer to the same elements. In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of one or more embodiments. However, it will be apparent, however, that such embodiments may be practiced without these specific details.

[0032] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. The terminology used herein, including technical and scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms used herein, such as those defined in commonly used dictionaries, may be interpreted as having the same meaning as in the context of the relevant technical field and should not be construed as having an ideal or overly formal meaning unless explicitly defined in this disclosure. In some cases, even terms defined in this disclosure should not be construed as excluding embodiments of this disclosure.

[0033] In the following description, for ease of description, terms referring to signals (e.g., message, signal, signaling, sequence, and stream), terms referring to resources (e.g., symbol, time slot, subframe, radio frame (RF), subcarrier, resource element (RE), resource block (RB), bandwidth portion (BWP), and timing) are used by way of example, terms for operation (e.g., step, method, processing, and procedure), terms referring to data (e.g., information, parameter, variable, value, bit, symbol, and codeword), terms referring to channels, terms referring to control information (e.g., downlink control information (DCI), media access control codeword element (MAC CE), and radio access control (RRC) signaling), terms referring to network entities, terms referring to device elements, etc., are used. Therefore, this disclosure is not limited to the terms described below, and other terms with equivalent technical meanings may be used.

[0034] This document describes various embodiments of the present disclosure in conjunction with wireless terminals and / or base stations. A wireless terminal can refer to a device that provides voice and / or data connectivity to a user. A wireless terminal can be connected to a computing device such as a laptop or desktop computer, or it can be a standalone device such as a personal digital assistant (PDA). A wireless terminal can also be referred to as a system, user unit, user station, mobile station, mobile station, remote station, remote terminal, access terminal, user terminal, terminal, wireless communication device, user agent, user apparatus, or user equipment. A wireless terminal can be a subscriber station, wireless device, cellular phone, PCS phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, personal digital assistant (PDA), handheld device with wireless connectivity, or other processing device connected to a wireless modem. A base station (e.g., an access point) can refer to a device in an access network that communicates with the wireless terminal over one or more sectors on an air interface. A base station can act as a router between the wireless terminal and the rest of the access network, which may include an Internet Protocol (IP) network, by converting received air interface frames into IP packets. The base station can also coordinate the management of the attributes of the air interface.

[0035] The embodiments disclosed herein consider a MIMO-OFDM system that uses a code division multiplexing (CDM) scheme as the signal multiplexing scheme. Furthermore, in this disclosure, it is assumed that the demodulation reference signal (DM-RS) known to the receiver passes through resource elements within a resource block. Resource element transfer is performed to estimate the channel for each CDM group.

[0036] The embodiments disclosed herein relate to wireless communication systems, and more specifically, assume multi-user multiple-input multiple-output (MU-MIMO) systems. MIMO communication systems are used as a key element technology in various wireless communication systems because they are technologies capable of significantly improving the transmission speed and communication stability of wireless communication.

[0037] In the normal operation of transmitting and receiving DMRS, the base station can send information about the time slot (N+1) in time slot N, used for scheduling, to the UE along with the DCI. In this case, antenna port field information is included in the DCI field, and the UE can identify information about the number of CDM groups transmitted in the resources scheduled by the DCI, the DMRS port index allocated to the UE, the number of layers, and the number of fronthaul symbols to which the DMRS is mapped, based on the received antenna port field. For example, if UE 1 receives information related to antenna port 45 from the base station, the UE can identify the information based on antenna port 45.

[0038] The embodiments presented in this document propose a method for reducing the overhead of the demodulation reference signal (DMRS) associated with multilayer transmission in MU-MIMO systems.

[0039] In MU-MIMO systems, a large number of DMRS ports may be required when transmitting multi-layer DMRS. In this case, since DMRS is transmitted in every time slot, overhead due to DMRS transmission can occur when transmitting a large number of layers. As the number of DMRS ports increases, the number of resource elements (REs) occupied by DMRS increases, thus reducing the number of REs available for data signal transmission, potentially leading to a rapid decline in UE transmission performance. For example, in the case of Type 2 DMRS, approximately 14.3% overhead due to DMRS transmission may occur for multi-layer (12-layer) transmission, and 57.1% overhead may occur for multi-layer (48-layer) transmission.

[0040] Therefore, this disclosure proposes a DMRS operation method that can reduce the overhead of DMRS transmission when DMRS is transmitted through a large number of layers in a 6G communication system.

[0041] Embodiments of this disclosure assume a scheme in which, when DMRS is transmitted through multiple layers in a MU-MIMO system, DMRS is transmitted intermittently (or in a segmented manner) rather than in every time slot, depending on the UE's transmission environment (e.g., modulation and coding scheme (MCS), signal-to-noise ratio (SNR), or mobility). For example, as Figure 2 and Figures 4 to 10 As shown, the embodiments of this disclosure assume that DMRS is not transmitted in a specific time slot or that some DMRS ports in a specific time slot are not transmitted.

[0042] Figure 1 An example of a radio resource area in a wireless communication system according to an embodiment of the present disclosure is shown.

[0043] In various embodiments of this disclosure, the radio resource domain may include a time-frequency domain structure. According to embodiments, the wireless communication system may include an NR communication system.

[0044] Reference Figure 1 In the radio resource area, the horizontal axis indicates the time domain, and the vertical axis indicates the frequency domain. Radio frame 104 is 10 ms long. Radio frame 104 can be configured with a time-domain interval of 10 subframes. Subframe 203 is 1 ms long. The constituent units in the time domain can be Orthogonal Frequency Division Multiplexing (OFDM) and / or Discrete Fourier Transform (DFT)-Extended-OFDM (DFT-s-OFDM) symbols, and a set of... One OFDM symbol and / or DFT-s-OFDM symbol 101 can constitute a time slot 102. In various embodiments, OFDM symbols may include symbols for transmitting / receiving signals using an OFDM multiplexing scheme, and DFT-s-OFDM symbols may include symbols for transmitting / receiving signals using a DFT-s-OFDM or single-carrier frequency division multiple access (SC-FDMA) multiplexing scheme. The smallest transmission unit in the frequency domain is a subcarrier, and the carrier bandwidth constituting the resource grid can be composed of a total Each subcarrier is configured 105 times. Furthermore, for ease of description, this document will describe an embodiment relating to downlink signal transmission / reception, but this also applies to embodiments relating to uplink signal transmission / reception.

[0045] In some embodiments, the number of time slots 103 constituting a subframe 102 and the length of time slot 102 can vary according to the subcarrier spacing. This subcarrier spacing can be referred to as a parameter set (μ). That is, the subcarrier spacing, the number of time slots included in the subframe, the length of the time slots, and the length of the subframe can be variably configured. For example, in an NR communication system, when the subcarrier spacing (SCS) is 15 kHz, one time slot 102 can constitute one subframe 103, and the lengths of time slot 102 and subframe 103 can each be 1 ms. Furthermore, for example, when the subcarrier spacing is 30 kHz, two time slots can constitute one subframe 103. In this case, the length of the time slot is 0.5 ms, and the length of the subframe is 1 ms.

[0046] In some embodiments, the subcarrier spacing, the number of time slots included in a subframe, the length of the time slots, and the length of the subframe can be variably applied depending on the communication system. For example, in the case of an LTE system, the subcarrier spacing is 15 kHz, two time slots constitute a subframe, and in this case, the length of the time slot can be 0.5 ms, and the length of the subframe can be 1 ms. For another example, in the case of an NR system, the subcarrier spacing (μ) can be one of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz, and the number of time slots included in a subframe can be 1, 2, 4, 8, and 16 depending on the subcarrier spacing (μ).

[0047] The basic unit of a resource in the time-frequency domain can be a resource element (RE) 106, and the resource element 106 can be represented by an OFDM symbol index and a subcarrier index. A resource block can include multiple resource elements. In an NR system, a resource block (RB) (or physical resource block (PRB)) 107 can be defined as a continuous array in the frequency domain. The number of subcarriers. The frequency domain can be 12. The frequency domain can include shared resource blocks (CRBs). Physical resource blocks (PRBs) can be defined within the bandwidth portion (BWP) of the frequency domain. CRB and PRB numbers can be determined based on the subcarrier spacing. In LTE systems, RBs can be defined as consecutive units in the time domain. OFDM symbols and continuous frequency domain Subcarriers.

[0048] In NR and / or LTE systems, scheduling information for downlink data or uplink data can be transmitted from the base station to the UE via downlink control information (DCI). In various embodiments, the DCI can be defined according to various formats, and each format can indicate whether the DCI includes scheduling information for uplink data (e.g., UL authorization), whether the DCI includes scheduling information for downlink data (DL resource allocation), whether the DCI is a compact DCI with small-size control information, whether the DCI is a backoff DCI, whether spatial multiplexing using multiple antennas is applied, and / or whether the DCI is a DCI for power control. For example, NR DCI format 1_0 or NR DCI format 1_1 may include scheduling for downlink data. Additionally, for example, NR DCI format 0_0 or NR DCI format 0_1 ​​may include scheduling for uplink data.

[0049] As mentioned above, Figure 1 An example of downlink and uplink time slot structure in a wireless communication system is illustrated. Specifically, Figure 1 The structure of the resource grid in a 3GPP NR system is illustrated. (Reference) Figure 1 A time slot can include multiple Orthogonal Frequency Division Multiplexing (OFDM) symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. The signal can be configured using a portion or all of the resource grid. Furthermore, the number of OFDM symbols included in a time slot can typically vary depending on the length of the cyclic prefix (CP). Figure 1 For ease of description, a time slot configured with 14 OFDM symbols is shown, but in the case of the signals mentioned in this disclosure, the symbol configuration is not specified. Furthermore, the modulation scheme of the generated signal is not limited to a specific value of Quadrature Amplitude Modulation (QAM) and can follow modulation schemes of various communication standards, such as Binary Phase Shift Keying (BPSK) and Quadrature Phase Shift Keying (QPSK).

[0050] Although various embodiments of this disclosure have been described based on LTE or NR communication systems, the scope of this disclosure is not limited thereto and can be applied to various wireless communication systems for transmitting downlink or uplink control information. Furthermore, it is apparent that the scope of this disclosure can also be applied to unlicensed and licensed frequency bands as needed.

[0051] In the following description of this disclosure, higher-layer signaling can be executed or higher-layer signals can be transmitted via signaling transmission methods, in which a base station transmits signals to a user terminal (UE) using a downlink data channel of the physical layer, or a UE transmits signals to a base station using an uplink data channel of the physical layer. According to embodiments, higher-layer signaling may include at least one of Radio Resource Control (RRC) signaling, signaling based on the F1 interface between a centralized unit (CU) and a distributed unit (DU), or a method of transmitting signals via a Media Access Control (MAC) control element (MAC CE). Additionally, according to embodiments, higher-layer signaling or higher-layer signals may include system information, such as a System Information Block (SIB), typically transmitted to multiple UEs.

[0052] In 5G wireless communication systems, a synchronization signal block (SSB) (or SS block, SS / PBCH block, etc.) can be sent for initial access, and the synchronization signal block can be configured by a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). During the initial access procedure when a UE first accesses the system, the UE can obtain downlink time-domain and frequency-domain synchronization and obtain the cell ID from the synchronization signal through a cell search process. The synchronization signal can include the PSS and SSS. The UE can receive the PBCH, including the primary information block (MIB), from the base station to obtain basic parameter values ​​and system information related to transmission and reception, such as system bandwidth or related control information. Based on the received PBCH, the UE can obtain the system information block (SIB) by decoding the physical downlink control channel (PDCCH) and the physical downlink shared channel (PDSCH). Afterward, the UE can exchange identities with the base station through random access procedures and can initially access the network through steps such as registration and authentication.

[0053] Figure 2 The resource structure in the case of switching the demodulation reference signal (DMRS) port according to an embodiment of the present disclosure is shown.

[0054] Figure 2 An example of DMRS port handover is provided, assuming a scenario where 24 DMRS ports are divided into two subsets (G=2) and six UEs are scheduled simultaneously. Figure 2The resource structure may include CDM groups 1 to 6 for DMRS. In this case, CDM groups 1 to 6 may refer to signals transmitted to UE 1 to UE 6 and signals received from UE 1 to UE 6, respectively.

[0055] refer to Figure 2 In the case of DMRS port switching mode ID 1, all DMRS ports can be sent in time slot 0, and no DMRS ports can be sent in time slot 1. Alternatively, all DMRS ports can be sent in time slot 2, and no DMRS ports can be sent in time slot 3.

[0056] In DMRS port switching mode ID 2, all DMRS ports can be sent in time slot 0, and no DMRS ports can be sent in time slot 1. In time slot 2, only the DMRS ports corresponding to CDM group 0, CDM group 1, and CDM group 2 can be sent, and in time slot 3, only the DMRS ports corresponding to CDM group 3, CDM group 4, and CDM group 5 can be sent.

[0057] Therefore, there may be time slots that do not transmit through the DMRS port.

[0058] Figure 3 An example of DMRS port switching according to an embodiment of the present disclosure is shown. Figure 3 The switch and Figure 2 The operation of the DMRS port corresponding to the resource structure shown.

[0059] Reference Figure 3 ,exist Figure 2 In the case of DMRS port switching mode ID 2, only the DMRS ports corresponding to CDM group 0, CDM group 1 and CDM group 2 can be sent in time slot 2, and the DMRS ports corresponding to CDM group 3, CDM group 4 and CDM group 5 can be omitted.

[0060] Therefore, in time slot 2, UEs 1 to UE 3, corresponding to CDM groups 0, 1, and 2 respectively, can receive DMRS. Since DMRS is not sent to UEs 4 to UE 6, corresponding to CDM groups 3, 4, and 5 respectively, the UEs can receive data signals.

[0061] Figure 4 An example is shown of a base station sending a signal including a DMRS null indicator to a UE in the event of a DMRS port handover, according to an embodiment of the present disclosure.

[0062] Figure 4This example illustrates a DMRS port handover scenario using 12 layers (L=12), performing DMRS transmission and reception through 12 DMRS ports, and simultaneously scheduling three UEs. Additionally, it is assumed that four layers are assigned to each UE.

[0063] According to embodiments of this disclosure, in resources where the base station does not transmit DMRS to the UE, data signals can be transmitted, but DMRS for data signals may not be transmitted. Accordingly, the base station can notify the UE via a DMRS null indicator that DMRS is not being transmitted on the DMRS port associated with the UE, and that the UE should reuse the most recently acquired DMRS. That is, the DMRS allocation information received by the UE from the base station may include a DMRS null indicator. The DMRS null indicator can indicate information about DMRS not being transmitted on the DMRS port associated with the UE and that the UE should reuse the DMRS port most recently received by the UE. Simultaneously, the DMRS null indicator can be transmitted from the base station to the UE via DCI or MAC CE.

[0064] According to embodiments of this disclosure, when the DMRS null indicator is 1, DMRS is not transmitted; instead, data signals are transmitted within the resources allocated to the UE. Therefore, the DMRS null indicator can indicate the reuse of the most recently acquired DMRS port. When the DMRS null indicator received from the base station is 1, the UE can demodulate data signals of the Physical Downlink Shared Channel (PDSCH) scheduled by the DCI or data signals of the PDSCH indicated by the MAC CE by using the most recently acquired DMRS port. For example, refer to… Figure 4 In time slot 5, UEs 1 through UE 3 can be assigned to CDM groups 0, 1, and 2 respectively, and can transmit DMRS ports corresponding to CDM groups 0, 1, and 2. When a DCI is transmitted to UE 1 in time slot 5, which is used for scheduling time slot 6, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS null indicator is 1, indicating that there are no DMRS allocated resources in time slot 6. Based on the information received from the base station indicating that the DMRS null indicator for time slot 6 is 1, UE 1 can decode the PDSCH data signal using the DMRS port most recently acquired by UE 1.

[0065] According to embodiments of this disclosure, when the DMRS null indicator is 0, DMRS is transmitted in the resources allocated to the UE; therefore, the DMRS null indicator can indicate that the recently acquired DMRS port does not need to be reused. For example, in Figure 4In the context of a DCI being sent to UE 1 in time slot 6 (which is used for scheduling time slot 7), the base station can send a DCI that includes not only information about the antenna port but also information indicating that the DMRS null indicator is 0. This indicates that DMRS will be sent in time slot 7 on the DMRS port corresponding to CDM group 0 associated with UE 1. Based on the information received from the base station indicating that the DMRS null indicator for time slot 7 is 0, UE 1 can receive the DMRS.

[0066] Figure 5 The resource structure in the case of DMRS port switching according to an embodiment of the present disclosure is shown.

[0067] In resources associated with CDM groups that do not transmit DMRS, data signals for the UE can actually be transmitted. However, the UE may incorrectly identify that DMRS is being transmitted in a resource associated with a CDM group based on the antenna port value. In this case, the UE may be unable to receive data signals. Table 1 shows information regarding antenna port values ​​according to 3GPP TS 38.212. Specifically, Table 1 shows the number of CDM groups, DMRS ports, and the number of fronthaul symbols based on the antenna port values. In one example, the UE can identify the number of CDM groups, DMRS ports, and the number of fronthaul symbols based on Table 1 and the antenna port values.

[0068] [Table 1]

[0069] Table 7.3.1.2.2-4: Antenna Ports (1000+DMRS Ports) [38.212]

[0070]

[0071] For example, in Figure 5 In Table 1, UE 1, associated with CDM group 0 resources, can identify via antenna port 45 that DMRS is transmitted in time slot 6 in both CDM group 1 and CDM group 2. However, the data signal can actually be transmitted in the resources associated with CDM group 2. As another example, in Figure 5 In this context, UE 1, associated with CDM group 0 resources, can identify that DMRS is transmitted in CDM group 1 and CDM group 2 in time slot 7 via antenna port 45. However, in practice, data signals can be transmitted in the resources associated with CDM group 1.

[0072] A potential problem is that in resources that transmit data signals for other UEs but not DMRS, interference signals associated with UEs that are not transmitting DMRS cannot be correctly identified, and it may be difficult to mitigate inter-UE interference using MIMO receivers. For example, a UE may identify that DMRS is being transmitted based on antenna port values, but may not be able to identify interference signals caused by another UE (e.g., a hidden UE) that is actually transmitting data signals.

[0073] For example, in Figure 5 In this context, UE 1, associated with CDM group 0, can receive interference signals against UE 2 in time slot 6 via DMRS transmitted in CDM group 1, but may not be able to correctly receive interference signals against UE 3 in CDM group 2, which does not transmit DMRS. As another example, in... Figure 5 In this context, UE 1, associated with CDM group 0, can receive interference signals against UE 3 in time slot 7 via DMRS transmitted in CDM group 2, but may not be able to correctly receive interference signals against UE 2 in CDM group 1, which does not transmit DMRS.

[0074] Figure 6 An example is shown where, according to an embodiment of this disclosure, a base station transmits a signal to a UE including either an inactive DMRS field value or an active DMRS field value during a DMRS port handover in a time slot. Specifically, Figure 6 An embodiment is shown in which, when a DMRS port corresponding to some CDM groups that have been assigned DMRS is not sent due to a DMRS port switch, the base station sends a signal to the UE, wherein these CDM groups are known to the UE through the regular DMRS port field.

[0075] According to embodiments of this disclosure, a base station can notify a UE via signaling about resources that actually transmit data signals in a CDM group where DMRS is allocated and is known to the UE through a regular DMRS port field, even without DMRS transmission due to DMRS port switching. In this case, the information about resources transmitting data signals without DMRS transmission can be sent in the form of DCI or MAC CE. In one example, the base station can notify the UE about CDM groups in which DMRS is not transmitted within a CDM group where no UE is allocated. In this case, the information about CDM groups that do not transmit DMRS can be provided as an inactive DMRS field. In another example, the base station can notify the UE about CDM groups in which DMRS is transmitted for the UE within a CDM group where no UE is allocated. In this case, the information about CDM groups that transmit DMRS for the UE can be provided as an active DMRS field.

[0076] Reference Figure 6In time slot 5, CDM groups 1, 2, and 3 can be assigned to UE 1, UE 2, and 3 respectively, and DMRS ports corresponding to CDM groups 1, 2, and 3 can be transmitted. For example, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also an inactive DMRS field indicating that DMRS is not transmitted in the resources corresponding to CDM group 2 (e.g., inactive DMRS={CDM group 2}). Additionally, the base station can transmit a DCI that includes an active DMRS field indicating that DMRS is transmitted in the resources corresponding to CDM group 1 due to antenna port switching (e.g., active DMRS={CDM group 1}). Furthermore, for example, the DCI may further include an indication of a reference... Figure 4 The information described is a DMRS null indicator of 0.

[0077] The UE can identify resources that transmit data signals but do not transmit DMRS by using information about inactive or active DMRS fields received from the base station. The UE can calculate the covariance matrix based on the received data signals. Additionally, the UE can estimate the channel based on the received DMRS signals. The UE can receive data signals by calculating a Minimum Mean Square Error-Interference Suppression Combination (MMSE-IRC) receiver based on the covariance matrix and the estimated channel. The matrix of the MMSE-IRC receiver can refer to the covariance matrix estimated based on the MMSE channel. The matrix of the MMSE-IRC receiver can be calculated according to the equations shown in Table 2.

[0078] [Table 2]

[0079] MMSE-IRC based on data signals (Reference: 3GPP TR 36.829)

[0080]

[0081] In Table 2, This represents the weight matrix of the MMSE-IRC receiver. Let represent the channel estimation matrix, and Let represent the covariance matrix.

[0082] In one example, when UE 1 receives from the base station information indicating an inactive DMRS field corresponding to CDM group 2 or an active DMRS field corresponding to CDM group 1 (relative to...) Figure 6In time slot 6, UE 1 can identify that DMRS is not transmitted in CDM group 2 within time slot 6. Therefore, UE 1 can calculate the covariance matrix based on the data signal received in CDM group 2, and receive the data signal by calculating the MMSE-IRC receiver according to Table 2 based on the channel estimated in time slot 6.

[0083] In the example, when Figure 6 When scheduling for UE 1 for time slot 7 is performed in time slot 6, if antenna port 45 is allocated, the DMRS port corresponding to CDM group 1 may not actually be transmitted in time slot 7 due to DMRS port switching. In this case, the base station can notify the UE of information about the CDM group that does not transmit DMRS through the inactive DMRS field (inactive DMRS={CDM group 1}) or the active DMRS field (active DMRS={CDM group 2}) via the DCI or MAC CE sent to the UE. Since UE 1 can identify that DMRS is not transmitted in CDM group 1 in time slot 7, UE 1 can calculate the covariance matrix based on the data signal received in CDM group 1 and receive the data signal by calculating the MMSE-IRC receiver based on the channel estimated in time slot 7.

[0084] Figure 7 An example is shown where, during a DMRS port handover in a time slot, a base station transmits a signal including an interference reuse field to the UE, according to an embodiment of this disclosure. Specifically, Figure 7 The illustration shows an example in which the base station signals the UE to indicate that the interference information recently measured by the UE is also valid in a specific resource in which DMRS is not transmitted.

[0085] According to embodiments of this disclosure, the base station can notify the UE of information about the ID of a CDM group whose interference information is valid, as recently measured by the UE, via signaling. In this case, the information about the ID of the CDM group whose interference information is valid can be provided as an interference reuse field. The ID information of the CDM group whose interference information is valid can be sent in the form of DCI or MAC CE.

[0086] In the example, refer to Figure 7UE 1 can receive information from the base station via DCI or MAC CE indicating that interference information for CDM group 2 is valid in time slot 6 (e.g., interference reuse = {CDM group 2}). Based on the information received from the base station, UE 1 can reuse the interference information for CDM group 2 measured in time slot 5 in time slot 6. Additionally, UE 1 can measure the interference information for CDM group 1 based on the DMRS measured in time slot 6. UE 1 can calculate the MMSE-IRC receiver based on the reused interference information for CDM group 2 and the measured interference information for CDM group 1.

[0087] In the example, refer to Figure 7 UE 1 can receive information from the base station via DCI or MAC CE indicating that interference information for CDM group 1 is valid in time slot 7 (e.g., interference reuse = {CDM group 1}). UE 1 can reuse the interference information for CDM group 1 measured in time slot 6 based on the information received from the base station in time slot 7. Additionally, UE 1 can measure the interference information for CDM group 2 based on the DMRS measured in time slot 7. UE 1 can calculate the MMSE-IRC receiver based on the reused interference information for CDM group 1 and the measured interference information for CDM group 2.

[0088] Figure 8 An example is shown where a base station sends a DMRS port handover mode to a UE in a super time slot according to an embodiment of this disclosure. Specifically, Figure 8 An example is shown where the base station performs DMRS port handover based on RRC signaling when 12 DMRS ports are transmitted in a super-slot structure.

[0089] Figures 2 to 7 The operation of the base station and UE based on a general time-slot structure is described, and Figure 8 The operation of a base station and a UE based on a super-timeslot structure that combines multiple time slots is described. A super-timeslot structure can represent a structure that combines multiple time slots within a general time slot structure as the time slot length shortens in the centimeter-wave band. In a super-timeslot structure, the UE can receive scheduling information for multiple time slots (i.e., super-timeslots) through a single DCI, instead of receiving scheduling information for a single time slot through a single DCI from the base station. Simultaneously, a super-timeslot can indicate multiple time slots.

[0090] The length of a superslot can be configured via RRC signaling. The length of a superslot indicates the number of slots combined within it. For example, the length of a superslot can be configured via PDSCH.

[0091] According to embodiments of this disclosure, the base station can notify information about the mode in which DMRS port switching is performed in multiple time slots via RRC signaling. Additionally, the base station can indicate one of the DMRS port switching modes via DCI or MAC CE. Therefore, the UE can identify the mode in which DMRS port switching is performed for multiple time slots.

[0092] Information regarding DMRS port switching modes may include defining possible DMRS port switching modes based on the DMRS port switching cycle and mapping mode IDs to each DMRS port switching mode, enabling signaling of the DMRS port switching mode via DCI or MACCE. In this case, the DMRS port switching cycle may indicate the period of the time slot in which all DMRS ports are transmitted. The DMRS port switching cycle may be less than the length of the timeout slot.

[0093] For example, Table 3 can indicate information about DMRS port switching modes.

[0094] [Table 3]

[0095] DMRS port switching cycle = 4 time slots, Type 2 DMRS

[0096]

[0097] Table 3 shows the ID (mode ID) used for DMRS port switching modes and information about the DMRS allocated to each time slot according to the DMRS port switching cycle. Table 3 shows information about the DMRS allocated to the first through fourth time slots when the DMRS port switching cycle is 4 (i.e., it can indicate the case where the number of combined time slots is 4).

[0098] The UE can identify the resources allocated for DMRS or data signals for each time slot based on information received from the base station regarding the DMRS port switching mode, and can receive the signals.

[0099] According to embodiments of this disclosure, in Figure 8 In this context, UE 1 can receive information about the DMRS port handover mode from the base station via RRC signaling. Additionally, UE 1 can receive scheduling information for super time slot 5 (i.e., time slots 6 to 9) from the base station via DCI in time slot 5. In one example, the scheduling information may include information indicating that the DMRS port handover mode ID is 0 (i.e., DMRS port handover mode ID = 0) and information indicating antenna port 45 (i.e., antenna port = 45).

[0100] UE 1 can identify, based on the information in Table 3 regarding DMRS port switching modes, that the DMRS port switching mode indicated by DMRS port switching mode ID0 is applied to super slot 5. For example, according to Table 3, UE 1 can identify that in the first slot of super slot 5 ( Figure 8 All DMRS ports are sent in slot 6, and in the second slot of super slot 5 ( Figure 8 DMRS is not transmitted in slot 7. Additionally, according to Table 3, UE 1 can identify that in the third slot of super slot 5 (… Figure 8 In slot 8), only the DMRS ports corresponding to CDM group 0 and CDM group 1 are transmitted, and the DMRS ports corresponding to CDM group 2 are not transmitted, and in the fourth slot of super slot 5 ( Figure 8 In time slot 9), only the DMRS port corresponding to CDM group 2 is transmitted, and the DMRS ports corresponding to CDM group 0 and CDM group 1 are not transmitted. Afterwards, UE 1 can receive data signals and DMRS for each time slot corresponding to the time slot based on the DMRS port switching mode.

[0101] Figure 9 An example is shown where a base station sends a DMRS port handover mode to a UE in a super time slot according to an embodiment of this disclosure. Specifically, Figure 9 An example is shown where the base station switches DMRS ports based on RRC signaling when 24 DMRS ports are transmitted in a super-slot structure.

[0102] According to embodiments of this disclosure, in Figure 9 In this context, UE 1 can receive information about the DMRS port handover mode from the base station via RRC signaling. This information can refer to the information in Table 3. UE 1 can receive scheduling information for super time slot 5 (i.e., time slots 6 to 9) in time slot 5 via DCI from the base station. In one example, the scheduling information may include information indicating that the DMRS port handover pattern ID is 2 (i.e., DMRS port handover pattern ID = 2) and information indicating antenna port 45 (i.e., antenna port = 45).

[0103] UE 1 can identify that the DMRS port switching mode indicated by DMRS port switching mode ID2 is applied to super slot 5 based on the information about DMRS port switching modes in Table 4. Table 4 only shows the case where DMRS port switching mode ID is 2 in Table 3.

[0104] [Table 4]

[0105] DMRS port switching periodicity = 4 time slots, 24 DMRS ports, 6 CDM groups

[0106]

[0107] In the example, according to Table 4, when the DMRS port switching mode ID is 2, UE 1 can identify the first time slot in super time slot 5 ( Figure 9 All DMRS ports are sent in slot 6, and in the second slot of super slot 5 ( Figure 9 In slot 7, the DMRS port is not transmitted. Additionally, UE 1 can identify that when the DMRS port switching mode ID in Table 4 is 2, in the third slot of super slot 5 (… Figure 9 In slot 8, only the DMRS ports corresponding to CDM groups 0, 1, and 2 are transmitted, and the DMRS ports corresponding to CDM groups 3, 4, and 5 are not transmitted. UE 1 can identify the fourth slot of super slot 5 ( Figure 9 In time slot 9), only the DMRS ports corresponding to CDM group 3, CDM group 4 and CDM group 5 are transmitted, and the DMRS ports corresponding to CDM group 0, CDM group 1 and CDM group 2 are not transmitted.

[0108] Subsequently, UE 1 can receive DMRS and data signals from the identified DMRS port or from the various time slots where data signals are transmitted without transmitting DMRS.

[0109] Figure 10 An example is shown where, in the case of a DMRS port handover in a super slot according to an embodiment of the present disclosure, the base station sends a signal to the UE including a DMRS port handover mode and an inactive DMRS field.

[0110] When the base station only notifies the UE of information about all possible DMRS handover modes via RRC signaling, such as Figure 8 and Figure 9 As shown, signaling overhead may occur. Figure 10 This describes the operation of sending information about the DMRS switching mode not only through RRC signaling but also through DCI or MAC CE to reduce the likelihood of signaling overhead.

[0111] According to embodiments of this disclosure, in Figure 10In this context, UE 1 can receive scheduling information from the base station for Super Time Slot 5 (i.e., time slots 6 to 9) included in time slot 5 of the DCI received from the base station. The scheduling information may include information indicating that the DMRS port switching mode ID is 2 (i.e., DMRS port switching mode ID = 2) and that the antenna port is 30 (i.e., antenna port = 30). In this case, UE 1 can identify that four DMRS ports have been allocated to it and that six CDM groups exist in the scheduled PDSCH resources through DMRS port switching mode ID 2 and antenna port 30. UE 1 can identify that the DMRS port switching mode indicated by DMRS port switching mode ID 2 is applied to Super Time Slot 5. Specifically, when the DMRS port switching mode ID is 2 in Table 4, UE 1 can identify information indicating the DMRS allocation for each time slot. In the example, according to Table 4, when the DMRS port switching mode ID is 2, UE 1 can identify that in the first time slot of Super Time Slot 5 (… Figure 10 All DMRS ports are sent in slot 6, and in the second slot of super slot 5 ( Figure 10 In slot 7), the DMRS port is not transmitted.

[0112] In the example, when the DMRS port switching mode ID in Table 4 is 2, UE 1 can identify the third time slot in super time slot 5 ( Figure 10 In time slot 8, only DMRS ports corresponding to CDM groups 0, 1, and 2 are transmitted, while DMRS ports corresponding to CDM groups 3, 4, and 5 are not transmitted. However, when UE 3 is not scheduled in time slot 8 due to fairness or other reasons, DMRS may not be transmitted in CDM group 2 corresponding to UE 3. In this case, UE 1 can update the DMRS port not transmitted in CDM group 2 based on the inactive DMRS field value (inactive DMRS={CDM group 2}) received via DCI or MAC CE. That is, flexible DMRS port handover configuration is possible, where the information of the inactive DMRS field contained in DCI or MAC CE covers part of the information referenced by the DMRS port handover mode ID provided via RRC signaling. In this case, the operation of sending and receiving part of the information about the DMRS port handover mode via DCI or MAC CE in addition to RRC signaling can be called hybrid signaling. Compared to using only DMRS port switching mode information provided via RRC signaling, receiving DMRS information via hybrid signaling and applying the received information can more effectively reduce the incidence of overhead.

[0113] In one example, in addition to DMRS handover mode information via RRC signaling, the base station can also send DMRS information to the UE via DCI or MAC CE, which can be active DMRS field information. Alternatively, the base station can simultaneously notify the UE of both inactive and active DMRS field information via DCI or MAC CE.

[0114] UE 1 can identify the fourth time slot in super time slot 5 ( Figure 9 In time slot 9, only the DMRS ports corresponding to CDM group 3, CDM group 4 and CDM group 5 are transmitted, and the DMRS ports corresponding to CDM group 0, CDM group 1 and CDM group 2 are not transmitted.

[0115] Subsequently, UE 1 can receive DMRS and data signals from the identified DMRS port or from the various time slots where data signals are transmitted without transmitting DMRS.

[0116] Figure 11 The operation of the base station and UE in the event of a DMRS port handover is illustrated according to an embodiment of the present disclosure.

[0117] refer to Figure 11 In operation 1110, the base station can identify DMRS ports that do not transmit DMRS but transmit data signals. In the example, in order to send scheduling information for time slot 6 to the UE in time slot 5, Figure 4 The base station can identify DMRS ports that do not transmit DMRS but transmit data signals in time slot 6.

[0118] In operation 1120, the base station can send DMRS allocation information and scheduling information to the UE.

[0119] According to embodiments of this disclosure, DMRS allocation information may include information about a DMRS empty indicator. The base station can send the DMRS empty indicator and scheduling information to the UE via DCI or MAC CE. The DMRS empty indicator may indicate that the UE will reuse the most recently received DMRS because no DMRS was transmitted on the DMRS port associated with the UE.

[0120] For example, in Figure 4 In this context, when the DMRS null indicator is 1, no DMRS is transmitted; instead, data signals are transmitted within the resources allocated to the UE. Therefore, the DMRS null indicator can indicate the reuse of the most recently acquired DMRS port. When the DMRS null indicator received from the base station is 1, the UE can demodulate PDSCH data signals scheduled by the DCI or indicated by the MAC CE using the most recently acquired DMRS port. (See reference...) Figure 4In time slot 5, CDM groups 1, 2, and 3 can be allocated to UE 1, UE 2, and UE 3, respectively, and DMRS ports corresponding to CDM groups 1, 2, and 3 can be transmitted. For example, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS null indicator is 1, indicating that there are no resources allocated for DMRS in time slot 6. Based on the information received from the base station indicating that the DMRS null indicator for time slot 6 is 1, the UE can decode the PDSCH data signal by using the most recently acquired DMRS port.

[0121] According to embodiments of this disclosure, DMRS allocation information may include information about inactive or active DMRS field values. The base station can transmit inactive or active DMRS field values ​​to the UE via DCI or MAC CE. Inactive DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are not sending DMRS values. Active DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are sending DMRS values.

[0122] In the example, Figure 6 In this scenario, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE1, the base station may transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also an inactive DMRS field indicating that DMRS is not being transmitted in the resources corresponding to CDM group 2 (e.g., inactive DMRS={CDM group 2}). In this case, the base station may also transmit a DCI that includes an active DMRS field indicating that DMRS is being transmitted in the resources corresponding to CDM group 1 due to antenna port switching (e.g., active DMRS={CDM group 1}).

[0123] According to embodiments of this disclosure, DMRS allocation information may include information about interference reuse field values. The base station can send the interference reuse field values ​​to the UE via DCI or MAC CE. The interference reuse field values ​​may indicate information about the ID of a CDM group that is valid for interference information most recently measured by the base station.

[0124] In the example, Figure 7 In this context, UE 1 can receive information from the base station via DCI or MAC CE indicating that the interference information of CDM group 2 is valid in time slot 6 (e.g., interference reuse = {CDM group 2}).

[0125] According to embodiments of this disclosure, a base station can send information about multiple DMRS port handover modes to a UE via RRC signaling. The information about the DMRS port handover modes can indicate the mode for performing DMRS port handover for multiple time slots in a supertime slot structure.

[0126] In the example, Figure 8 In this context, UE 1 can receive information about the DMRS port handover mode from the base station via RRC signaling. Additionally, UE 1 can receive scheduling information for super time slot 5 (i.e., time slots 6 to 9) from the base station via DCI in time slot 5. For example, the scheduling information may include information indicating that the DMRS port handover mode ID is 0 (i.e., DMRS port handover mode ID = 0) and information indicating antenna port 45 (i.e., antenna port = 45).

[0127] According to embodiments of this disclosure, a base station can transmit information about the DMRS handover mode via RRC signaling and DCI or MAC CE. For example, in Figure 10 In this configuration, the base station can send DMRS port switching mode information to UE 1 via RRC signaling, and can also send inactive DMRS field values ​​to UE 1 via DCI or MAC CE. In addition to inactive DMRS field values, active DMRS field values ​​can also be sent.

[0128] In operation 1130, the UE can identify the data signal used for the Physical Downlink Shared Channel (PDSCH) and the DMRS port allocated to the DMRS based on the DMRS allocation information received from the base station.

[0129] The DMRS allocation information received by the UE from the base station via DCI or MAC CE may be one of the following: DMRS empty indicator, inactive DMRS field value / active DMRS field value, interference reuse field value, or information indicating DMRS port switching mode, which is sent by the base station in Operation 1120.

[0130] According to embodiments of this disclosure, when a UE receives information from a base station indicating that the DMRS null indicator is 1, the UE can demodulate the data signal of the Physical Downlink Shared Channel (PDSCH) scheduled by the DCI, or the data signal of the PDSCH indicated by the MAC CE, by using the most recently acquired DMRS port. For example, refer to... Figure 4In time slot 5, UEs 1 through UE 3 can be assigned to CDM groups 1, 2, and 3 respectively, and can transmit DMRS ports corresponding to CDM groups 1, 2, and 3. When transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS empty indicator is 1, indicating that there are no DMRS allocated resources in time slot 6. Based on the information received from the base station indicating that the DMRS empty indicator for time slot 6 is 1, UE 1 can decode the PDSCH data signal using the DMRS port most recently acquired by UE 1.

[0131] According to embodiments of this disclosure, when a UE receives information from a base station indicating that the DMRS null indicator is 0, the DMRS null indicator can instruct the transmission of DMRS on the DMRS port corresponding to the CDM group allocated to the UE. Therefore, the DMRS port recently acquired by the UE does not need to be reused. For example, in Figure 4 In the context of a DCI sent in time slot 6 to schedule time slot 7 for UE1, the base station can send a DCI that includes not only information about the antenna port but also information indicating that the DMRS null indicator is 0. This indicates that DMRS should be sent in time slot 7 on the DMRS port corresponding to CDM group 0 associated with UE1. Based on the information received from the base station indicating that the DMRS null indicator for time slot 7 is 0, UE1 can receive the DMRS.

[0132] According to embodiments of this disclosure, when a UE receives information from a base station about an inactive or active DMRS field, the UE can identify resources that do not transmit DMRS but transmit data signals.

[0133] According to embodiments of this disclosure, when a UE receives information about an interference reuse field value from a base station, the UE can reuse the interference information about CDM group 2 indicated by the interference reuse field value.

[0134] According to embodiments of this disclosure, when a UE receives information about a DMRS port switching mode from a base station via RRC signaling, the UE can identify the DMRS port switching mode mapped to information indicating the DMRS port switching mode received via DCI or MAC CE.

[0135] In operation 1140, the base station can send DMRS and data signals to the UE. The UE can receive data signals and DMRS for PDSCH based on the identified DMRS port.

[0136] In operation 1150, the UE can demodulate the PDSCH based on the received DMRS and data signals. The UE can calculate the covariance matrix based on the received data signals. Additionally, the UE can estimate the channel based on the received DMRS signal. The UE can receive data signals by calculating a Minimum Mean Square Error-Interference Suppression Combination (MMSE-IRC) receiver based on the covariance matrix and the estimated channel. The matrix of the MMSE-IRC receiver can refer to the covariance matrix estimated based on the MMSE channel. The matrix of the MMSE-IRC receiver can be calculated according to the equations shown in Table 2 above.

[0137] Figure 12 Operation of a UE according to an embodiment of this disclosure is illustrated.

[0138] exist Figure 12 In operation 1210, the UE can receive at least one of MAC CE or DCI, which includes DMRS allocation information and scheduling information, from the base station.

[0139] According to embodiments of this disclosure, DMRS allocation information may include information about a DMRS empty indicator. The base station can send the DMRS empty indicator and scheduling information to the UE via DCI or MAC CE. The DMRS empty indicator may indicate that, since no DMRS was sent, the information of the most recently acquired DMRS should be reused.

[0140] For example, in Figure 4 In this context, when the DMRS null indicator is 1, no DMRS is transmitted; instead, data signals are transmitted within the resources allocated to the UE. Therefore, the DMRS null indicator can indicate the reuse of the most recently acquired DMRS port. When the DMRS null indicator received from the base station is 1, the UE can demodulate PDSCH data signals scheduled by the DCI or indicated by the MAC CE using the most recently acquired DMRS port. (See reference...) Figure 4 In time slot 5, UE 1, UE 2, and UE 3 can be assigned to CDM group 1, CDM group 2, and CDM group 3, respectively, and can transmit DMRS ports corresponding to CDM group 1, CDM group 2, and CDM group 3. For example, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS null indicator is 1, indicating that there are no resources allocated for DMRS in time slot 6. Based on the information received from the base station indicating that the DMRS null indicator for time slot 6 is 1, UE 1 can decode the data signal for PDSCH by using the most recently acquired DMRS port.

[0141] According to embodiments of this disclosure, DMRS allocation information may include information about inactive or active DMRS field values. The base station can transmit inactive or active DMRS field values ​​to the UE via DCI or MAC CE. Inactive DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are not sending DMRS values. Active DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are sending DMRS values.

[0142] In the example, Figure 6 In this scenario, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE1, the base station may transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also an inactive DMRS field (e.g., inactive DMRS={CDM group 2}) indicating that DMRS is not being transmitted in the resources corresponding to CDM group 2. In this case, the base station may also transmit a DCI that includes an active DMRS field indicating that DMRS is being transmitted in the resources corresponding to CDM group 1 due to antenna port switching (e.g., active DMRS={CDM group 1}).

[0143] According to embodiments of this disclosure, DMRS allocation information may include information about interference reuse field values. The base station can send the interference reuse field values ​​to the UE via DCI or MAC CE. The interference reuse field values ​​may indicate information about the ID of a CDM group that is valid for interference information most recently measured by the base station.

[0144] In the example, Figure 7 In this context, UE 1 can receive information from the base station via DCI or MAC CE indicating that the interference information of CDM group 2 is valid in time slot 6 (e.g., interference reuse = {CDM group 2}).

[0145] According to embodiments of this disclosure, a base station can send information about multiple DMRS port handover modes to a UE via RRC signaling. The information about the DMRS port handover modes can indicate the mode for performing DMRS port handover for multiple time slots in a supertime slot structure.

[0146] In the example, Figure 8 In this context, UE 1 can receive information about the DMRS port handover mode from the base station via RRC signaling. Additionally, UE 1 can receive scheduling information for super time slot 5 (i.e., time slots 6 to 9) via DCI from the base station in time slot 5. For example, the scheduling information may include information indicating that the DMRS port handover mode ID is 0 (i.e., DMRS port handover mode ID = 0) and information indicating antenna port 45 (i.e., antenna port = 45).

[0147] According to embodiments of this disclosure, a base station can transmit information about the DMRS handover mode via RRC signaling and DCI or MAC CE. For example, in Figure 10 In this configuration, the base station can send DMRS port switching mode information to UE 1 via RRC signaling, and can also send inactive DMRS field values ​​to UE 1 via DCI or MAC CE. In addition to inactive DMRS field values, active DMRS field values ​​can also be sent.

[0148] In Operation 1220, the UE can identify the data signal used for the Physical Downlink Shared Channel (PDSCH) and the DMRS port allocated to the DMRS based on the DMRS allocation information received from the base station.

[0149] The DMRS allocation information received by the UE from the base station via DCI or MAC CE can be one of the following: a DMRS empty indicator received from the base station in Operation 1210, an inactive DMRS field value / active DMRS field value, an interference reuse field value, or information indicating the DMRS port switching mode.

[0150] According to embodiments of this disclosure, when a UE receives information from a base station that the DMRS null indicator is 1, the UE can demodulate the data signal of the Physical Downlink Shared Channel (PDSCH) scheduled by the DCI or the data signal of the PDSCH indicated by the MAC CE by using the most recently acquired DMRS port. For example, refer to... Figure 4 In time slot 5, UE 1, UE 2, and UE 3 can be assigned to CDM group 1, CDM group 2, and CDM group 3, respectively, and can transmit DMRS ports corresponding to CDM group 1, CDM group 2, and CDM group 3. When transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS empty indicator is 1, indicating that there are no DMRS allocated resources in time slot 6. Based on the information received from the base station indicating that the DMRS empty indicator for time slot 6 is 1, UE 1 can decode the PDSCH data signal by using the DMRS port most recently acquired by UE 1.

[0151] According to embodiments of this disclosure, when a UE receives information from a base station that the DMRS null indicator is 0, the DMRS null indicator can indicate that since the DMRS is transmitted on the DMRS port corresponding to the CDM group assigned to the UE, it is not necessary to reuse the most recently acquired DMRS port. For example, in Figure 4In the process of transmitting a DCI in time slot 6 to schedule time slot 7 for UE 1, the base station may transmit a DCI that includes not only information about the antenna port but also information indicating that the DMRS null indicator is 0, indicating that DMRS will be transmitted in time slot 7 on the DMRS port corresponding to CDM group 0 associated with UE 1. Based on the information received from the base station indicating that the DMRS null indicator for time slot 7 is 0, UE 1 can receive the DMRS.

[0152] According to embodiments of this disclosure, when a UE receives information from a base station about an inactive or active DMRS field, the UE can identify resources that transmit data signals but do not transmit DMRS.

[0153] According to embodiments of this disclosure, when a UE receives information about an interference reuse field value from a base station, the UE can reuse the interference information of CDM group 2 indicated by the interference reuse field value.

[0154] According to embodiments of this disclosure, when a UE receives information about a DMRS port switching mode from a base station via RRC signaling, the UE can identify a DMRS port switching mode mapped to information indicating the DMRS port switching mode received via DCI or MAC CE.

[0155] In Operation 1230, the UE can receive data signals for the PDSCH and DMRS based on the identified DMRS port.

[0156] In operation 1240, the UE can demodulate the PDSCH based on the received DMRS and data signals. The UE can calculate the covariance matrix based on the received data signals. Additionally, the UE can estimate the channel based on the received DMRS signal. The UE can receive data signals by calculating a Minimum Mean Square Error-Interference Suppression Combination (MMSE-IRC) receiver based on the covariance matrix and the estimated channel. The matrix of the MMSE-IRC receiver can refer to the covariance matrix estimated based on the MMSE channel. The matrix of the MMSE-IRC receiver can be calculated according to the equations in Table 2 above.

[0157] Figure 13 The operation of a base station according to an embodiment of the present disclosure is illustrated.

[0158] refer to Figure 13 In operation 1310, the base station can identify DMRS ports that do not send DMRS signals to it but do send data signals to it. In the example, in order to send scheduling information for time slot 6 to the UE in time slot 5, Figure 4 The base station can identify DMRS ports that do not transmit DMRS but transmit data signals in time slot 6.

[0159] In Operation 1320, the base station can send DMRS allocation information and scheduling information to the UE.

[0160] According to embodiments of this disclosure, DMRS allocation information may include information about a DMRS empty indicator. The base station can send the DMRS empty indicator and scheduling information to the UE via DCI or MAC CE. The DMRS empty indicator may indicate that, since no DMRS was sent, the information of the most recently acquired DMRS should be reused.

[0161] For example, in Figure 4 In this context, when the DMRS null indicator is 1, no DMRS is transmitted; instead, data signals are transmitted within the resources allocated to the UE. Therefore, the DMRS null indicator can indicate the reuse of the most recently acquired DMRS port. When the DMRS null indicator received from the base station is 1, the UE can demodulate PDSCH data signals scheduled by the DCI or indicated by the MAC CE using the most recently acquired DMRS port. (See reference...) Figure 4 In time slot 5, UE 1, UE 2, and UE 3 can be assigned to CDM group 1, CDM group 2, and CDM group 3, respectively, and can transmit DMRS ports corresponding to CDM group 1, CDM group 2, and CDM group 3. For example, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE 1, the base station can transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also information indicating that the DMRS null indicator is 1, indicating that there are no DMRS allocated resources in time slot 6. Based on the information received from the base station indicating that the DMRS null indicator for time slot 6 is 1, UE 1 can decode the data signal for PDSCH by using the most recently acquired DMRS port.

[0162] According to embodiments of this disclosure, DMRS allocation information may include information about inactive or active DMRS field values. The base station can transmit inactive or active DMRS field values ​​to the UE via DCI or MAC CE. Inactive DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are not sending DMRS values. Active DMRS field values ​​may indicate information about CDM groups within CDM groups where no UE has been assigned a DMRS field value, which are sending DMRS values.

[0163] In the example, Figure 6In this scenario, when transmitting a DCI in time slot 5 to schedule time slot 6 for UE1, the base station may transmit a DCI that includes not only information about the antenna port (e.g., information indicating antenna port 45) but also an inactive DMRS field indicating that DMRS is not transmitted in the resource corresponding to CDM group 2 (e.g., inactive DMRS={CDM group 2}). In this case, the base station may also transmit a DCI that includes an active DMRS field indicating that DMRS is transmitted in the resource corresponding to CDM group 1 due to antenna port switching (e.g., active DMRS={CDM group 1}).

[0164] According to embodiments of this disclosure, DMRS allocation information may include information about interference reuse field values. The base station can send the interference reuse field values ​​to the UE via DCI or MAC CE. The interference reuse field values ​​may indicate information about the ID of a CDM group that is valid for interference information most recently measured by the base station.

[0165] In the example, Figure 7 In this context, UE 1 can receive information from the base station via DCI or MAC CE indicating that the interference information of CDM group 2 is valid in time slot 6 (e.g., interference reuse = {CDM group 2}).

[0166] According to embodiments of this disclosure, a base station can send information about multiple DMRS port handover modes to a UE via RRC signaling. The information about the DMRS port handover modes can indicate the mode for performing DMRS port handover for multiple time slots in a supertime slot structure.

[0167] In the example, Figure 8 In this context, UE 1 can receive information about the DMRS port handover mode from the base station via RRC signaling. Additionally, UE 1 can receive scheduling information for super time slot 5 (i.e., time slots 6 to 9) from the base station via DCI in time slot 5. For example, the scheduling information may include information indicating that the DMRS port handover mode ID is 0 (i.e., DMRS port handover mode ID = 0) and information indicating antenna port 45 (i.e., antenna port = 45).

[0168] According to embodiments of this disclosure, a base station can transmit information about the DMRS handover mode via RRC signaling and DCI or MAC CE. For example, in Figure 10 In this configuration, the base station can send DMRS port switching mode information to UE 1 via RRC signaling, and can also send inactive DMRS field values ​​to UE 1 via DCI or MAC CE. In addition to inactive DMRS field values, active DMRS field values ​​can also be sent.

[0169] Figure 14 The structure of a UE 1400 according to various embodiments of the present disclosure is shown.

[0170] Figure 14 The structure shown can be understood as the structure of UE 1400. As used herein, terms such as “…unit” and “…device” can refer to a unit configured to perform at least one function or operation and can be implemented as hardware, software, or a combination of hardware and software.

[0171] refer to Figure 14 UE 1400 may include a communication unit 1410, a storage device 1420 and a controller 1430.

[0172] Communication unit 1410 performs functions for transmitting / receiving signals via a radio channel. For example, communication unit 1410 performs conversion between baseband signals and bit strings according to the system's physical layer specifications. For instance, during data transmission, communication unit 1410 encodes and modulates the transmitted bit string to generate complex symbols. Additionally, during data reception, communication unit 1410 demodulates and decodes the baseband signal to recover the received bit string. Furthermore, communication unit 1410 up-converts the baseband signal to an RF band signal, transmits the signal through an antenna, and down-converts the RF band signal received through the antenna back to a baseband signal. For example, communication unit 1410 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC.

[0173] Furthermore, communication unit 1410 may include multiple transmit / receive paths. Additionally, communication unit 1410 may include antenna elements. Communication unit 1410 may include at least one antenna array configured with multiple antenna elements. In terms of hardware, communication unit 1410 may include digital and analog circuitry (e.g., radio frequency integrated circuits (RFICs)). Here, the digital and analog circuitry may be implemented in a single package. Furthermore, communication unit 1410 may include multiple RF chains. Communication unit 1410 may perform beamforming. To assign directivity based on the configuration of controller 1430 to the signal to be transmitted / received, communication unit 1410 may apply beamforming weights to the signal. According to an embodiment, communication unit 1410 may include a radio frequency (RF) block (or RF unit). The RF block may include a first RF circuitry associated with an antenna and a second RF circuitry associated with baseband processing. The first RF circuitry may be referred to as an RF antenna (RF-A). The second RF circuitry may be referred to as an RF baseband (RF-B).

[0174] Additionally, the communication unit 1410 can transmit / receive signals. For this purpose, the communication unit 1410 may include at least one transceiver. The communication unit 1410 can receive downlink signals. Downlink signals may include synchronization signals (SS), reference signals (RS) (e.g., demodulation (DM)-RS or phase tracking reference signals (PTRS)), system information (e.g., MIB, SIB, residual system information (RMSI) or other system information (OSI)), configuration messages, control information, downlink data, etc. The communication unit 1410 can transmit uplink signals. Uplink signals may include random access related signals (e.g., random access preamble (RAP) (or message 1 (Msg1), message 3 (Msg3)), reference signals (e.g., sounding reference signals (SRS), DMRS, or PTRS), power headroom reports (PHR), etc.

[0175] Additionally, the communication unit 1410 may include different communication modules to process signals in different frequency bands. Furthermore, the communication unit 1410 may include multiple communication modules to support a variety of different radio access technologies. For example, different radio access technologies may include Bluetooth Low Energy (BLE), Wi-Fi, Wi-Fi Gigabit (WiGig), cellular networks (e.g., Long Term Evolution (LTE)), New Radio (NR), etc. Furthermore, different frequency bands may include ultra-high frequency (SHF) bands (e.g., 2.5 GHz or 5 GHz bands), millimeter wave (mmWave) bands (e.g., 38 GHz or 60 GHz bands), etc. Additionally, the communication unit 1410 can use the same radio access technology in different frequency bands (e.g., unlicensed bands for Licensed Assisted Access (LAA) and Citizens Broadband Radio Service (CBRS) (e.g., 3.5 GHz)).

[0176] Communication unit 1410 transmits and receives signals as described above. Therefore, all or part of communication unit 1410 may be referred to as a "transmitter," a "receiver," or a "transceiver." Additionally, as used in the following description, "transmission and reception performed via a radio channel" may include the meaning of the processing described above being performed by communication unit 1410.

[0177] Storage device 1420 can store basic programs, application programs, and data, such as configuration information, for the operation of UE 1400. Storage device 1420 may include volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. Additionally, storage device 1420 can provide stored data upon request from controller 1430.

[0178] Controller 1430 controls the overall operation of UE 1400. For example, controller 1430 sends and receives signals via communication unit 1410. Additionally, controller 1430 records data in storage device 1420 and reads data from storage device 1420. Furthermore, controller 1430 can perform the functions of the protocol stack required by the communication specifications. Controller 1430 may include at least one processor. Controller 1430 may include at least one processor or microprocessor, or may be part of a processor. Additionally, communication unit 1410 and a portion of controller 1430 may be referred to as CP. Controller 1430 may include various modules for performing communication. According to various embodiments, controller 1430 can control the UE to perform operations according to various embodiments.

[0179] Figure 15 The structure of a base station according to various embodiments of the present disclosure is shown.

[0180] Reference Figure 15 The base station 1500 includes a communication unit 1510, a storage device 1520, and a controller 1530.

[0181] Communication unit 1510 performs functions for transmitting / receiving signals via a radio channel. For example, communication unit 1510 performs the conversion between baseband signals and bit strings according to the system's physical layer specifications. For instance, during data transmission, communication unit 1510 encodes and modulates the transmitted bit string to generate complex symbols. Additionally, during data reception, communication unit 1510 demodulates and decodes the baseband signal to recover the received bit string. Furthermore, communication unit 1510 up-converts the baseband signal to a radio frequency (RF) band signal, transmits the up-converted RF band signal via an antenna, and then down-converts the RF band signal received via the antenna back to a baseband signal.

[0182] Therefore, the communication unit 1510 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. Additionally, the communication unit 1510 may include multiple transmit / receive paths. Furthermore, the communication unit 1510 may include at least one antenna array comprising multiple antenna elements. In terms of hardware, the communication unit 1510 may include digital and analog units, and the analog unit may include multiple sub-units depending on operating power, frequency, etc.

[0183] The communication unit 1510 can transmit / receive signals. For this purpose, the communication unit 1510 may include at least one transceiver. For example, the communication unit 1510 can transmit synchronization signals, reference signals, system information, messages, control information, data, etc. Furthermore, the communication unit 1510 can perform beamforming.

[0184] Communication unit 1510 transmits and receives signals as described above. Therefore, all or part of communication unit 1510 may be referred to as a "transmitter," a "receiver," or a "transceiver." Additionally, as used in the following description, "transmission and reception performed via a radio channel" may include the meaning of the processing described above being performed by communication unit 1510.

[0185] Storage device 1520 can store basic programs, application programs, and data such as configuration information for the operation of the base station. Storage device 1520 may include memory. Storage device 1520 may include volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, storage device 1520 provides stored data upon request from controller 1530.

[0186] Controller 1530 controls the overall operation of base station 1500. For example, controller 1530 sends and receives signals through communication unit 1510. Additionally, controller 1530 records data in storage device 1520 and reads data from storage device 1520. Controller 1530 can also perform the functions of the protocol stack required by the communication specifications. Controller 1530 may include at least one processor.

[0187] Figure 15 The structure of the base station 1500 shown is merely an example of a base station, and examples of base stations used to perform various embodiments of this disclosure are not limited to this. Figure 15 The structure shown is illustrated. That is, according to various embodiments of this disclosure, some components can be added, deleted, or modified.

[0188] exist Figure 15 In this disclosure, base station 1500 has been described as a single entity, but this disclosure is not limited thereto. In addition to integrated deployment, base station 1500 according to various embodiments of this disclosure can be implemented to construct an access network with a distributed deployment. According to embodiments, the base station can be divided into a central unit (CU) and a digital unit (DU), the CU being implemented to perform upper-layer functions (e.g., Packet Data Convergence Protocol (PDCP) and RRC), and the DU being implemented to perform lower-layer functions (e.g., Media Access Control (MAC) and Physical (PHY)). The DUs of the base station can form beam coverage over radio channels.

[0189] The embodiments of this disclosure described and illustrated in the specification and drawings are merely specific examples presented to facilitate the explanation of the technical content of the embodiments of this disclosure and to aid in the understanding of the embodiments of this disclosure, and are not intended to limit the scope of the embodiments of this disclosure. That is, it will be apparent to those skilled in the art that other variations based on the technical concept of this disclosure can be implemented. Furthermore, the various embodiments described above can be combined as needed.

[0190] As described above, according to the various embodiments disclosed herein, a method performed by a user equipment in a wireless communication system may include: receiving from a base station at least one of downlink control information (DCI) and media access control (MAC) control element (CE) including demodulation reference signal (DMRS) allocation information and scheduling information; identifying a data signal for a physical downlink shared channel (PDSCH) and a DMRS port allocated to the DMRS based on the DMRS allocation information; receiving the data signal and the DMRS based on the identified DMRS port; and demodulating the PDSCH based on the DMRS and the data signal.

[0191] According to the various embodiments disclosed herein, DMRS allocation information may include a DMRS null indicator, and the DMRS null indicator may indicate a DMRS port to be reused.

[0192] According to various embodiments disclosed herein, DMRS allocation information may include at least one of an inactive DMRS field value or an active DMRS field value, and the inactive DMRS field value may indicate information about a code division multiplexing (CDM) group in which DMRS is not transmitted in the CDM group in which DMRS is allocated.

[0193] According to various embodiments disclosed herein, DMRS allocation information may include an interference reuse field value, and the interference reuse field value may include information about the CDM group that is valid in the second time slot regarding interference information in the first time slot.

[0194] According to various embodiments disclosed herein, DMRS allocation information may include information indicating a DMRS port switching mode, and the method may include receiving DMRS port switching mode information from a base station via Radio Resource Control (RRC) signaling and identifying a DMRS port switching mode mapped from the DMRS port switching mode information to the information indicating the DMRS switching mode.

[0195] As described above, a user equipment according to various embodiments disclosed herein may include a transceiver and a controller coupled to the transceiver, wherein the controller is configured to receive from a base station at least one of downlink control information (DCI) and media access control (MAC) control element (CE) including demodulation reference signal (DMRS) allocation information and scheduling information, identify a data signal for a physical downlink shared channel (PDSCH) and a DMRS port allocated to the DMRS based on the DMRS allocation information, receive the data signal and the DMRS based on the identified DMRS port, and demodulate the PDSCH based on the DMRS and the data signal.

[0196] According to various embodiments disclosed herein, MRS allocation information may include information indicating a DMRS port switching mode, and the controller may be configured to receive DMRS port switching mode information from a base station via Radio Resource Control (RRC) signaling and identify from the DMRS port switching mode information a DMRS port switching mode mapped to the information indicating the DMRS switching mode.

[0197] As described above, according to the various embodiments disclosed herein, a method performed by a base station in a wireless communication system may include: identifying a demodulation reference signal (DMRS) port that transmits data signals but does not transmit DMRS; and sending at least one of downlink control information (DCI) and media access control (MAC) control element (CE) to a user equipment, including DMRS allocation information and scheduling information, wherein the user equipment uses the DMRS allocation information to identify the DMRS port allocated to the data signals and DMRS for the physical downlink shared channel (PDSCH).

[0198] According to various embodiments disclosed herein, the method may include sending DMRS port switching mode information to a user equipment via Radio Resource Control (RRC) signaling, wherein the DMRS allocation information includes information indicating a DMRS port switching mode, and wherein the information indicating a DMRS port switching mode is used by the user equipment to identify from the DMRS port switching mode information a DMRS port switching mode mapped to the information indicating a DMRS port switching mode.

[0199] As described above, a base station in a wireless communication system according to various embodiments disclosed herein may include a transceiver and a controller coupled to the transceiver, wherein the controller is configured to identify DMRS ports on which DMRS is not transmitted but data signals are transmitted, and to transmit at least one of a DCI and a MAC CE including DMRS allocation information and scheduling information to the UE, wherein the DMRS allocation information is used by the UE to identify DMRS ports on which DMRS and data signals for PDSCH are allocated.

[0200] According to various embodiments disclosed herein, the controller can be configured to send DMRS port switching mode information to the UE via RRC signaling, wherein the DMRS allocation information includes information indicating the DMRS port switching mode, and wherein the information indicating the DMRS port switching mode is used by the UE to identify from the DMRS port switching mode information a DMRS port switching mode mapped to the information indicating the DMRS port switching mode.

Claims

1. A method performed by a user equipment in a wireless communication system, the method comprising: Receive from the base station at least one of the following: downlink control information (DCI), media access control (MAC) control element (CE), and radio resource control (RRC) signaling, including demodulation reference signal (DMRS) allocation information and scheduling information; Based on DMRS allocation information, identify the data signals used for the Physical Downlink Shared Channel (PDSCH) and the DMRS ports allocated to the DMRS; The data signal and the DMRS are received based on the identified DMRS port; and The PDSCH is demodulated based on the DMRS and the data signal.

2. The method according to claim 1, wherein, The DMRS allocation information includes a DMRS empty indicator. The DMRS empty indicator is used to identify whether the DMRS is sent in the scheduled PDSCH, and The DMRS empty indicator indicates the reuse of a DMRS port channel that was previously allocated for PDSCH transmission.

3. The method according to claim 1, wherein, The DMRS allocation information includes at least one of an inactive DMRS field value and an active DMRS field value. The inactive DMRS field value indicates information about CDM groups that do not transmit the DMRS within the code division multiplexing (CDM) group that allocates the DMRS. The activated DMRS field value indicates information about the CDM group that sent the DMRS within the CDM group that allocated the DMRS, and The DMRS transmitted in the scheduled PDSCH is identified based on the inactive DMRS field value or the active DMRS field value and the specific antenna port value indicated by the DCI.

4. The method according to claim 1, wherein, The DMRS allocation information includes the interference reuse field value. The interference reuse field value includes information about the CDM group that is valid in the second time slot and the interference information in the first time slot.

5. The method according to claim 1, wherein, The DMRS allocation information includes information indicating the DMRS port switching mode, and the method includes: Receive DMRS port switching mode information from the base station via the RRC signaling; Receive information indicating the DMRS handover mode from the base station via DCI or MAC-CE; and Identify the DMRS port switching mode mapped to information indicating the DMRS switching mode. The DMRS port switching mode information includes multiple switching modes indicating inactive or active DMRS information in multiple time slots, and The PDSCH is demodulated based on the identified DMRS port switching mode.

6. A user equipment in a wireless communication system, comprising: transceiver; and A controller coupled to the transceiver The controller is configured as follows: Receive from the base station at least one of the following: downlink control information (DCI), media access control (MAC) control element (CE), and radio resource control (RRC) signaling, including demodulation reference signal (DMRS) allocation information and scheduling information; Based on DMRS allocation information, identify the data signals used for the Physical Downlink Shared Channel (PDSCH) and the DMRS ports allocated to the DMRS; The data signal and the DMRS are received based on the identified DMRS port; and The PDSCH is demodulated based on the DMRS and the data signal.

7. The user equipment according to claim 6, wherein, The DMRS allocation information includes a DMRS empty indicator. The DMRS empty indicator is used to identify whether the DMRS is sent in the scheduled PDSCH, and The DMRS empty indicator indicates the reuse of a DMRS port channel that was previously allocated for PDSCH transmission.

8. The user equipment according to claim 6, wherein, The DMRS allocation information includes at least one of an inactive DMRS field value and an active DMRS field value. The inactive DMRS field value indicates information about CDM groups that do not transmit the DMRS within the code division multiplexing (CDM) group that allocates the DMRS. The activated DMRS field value indicates information about the CDM group that sent the DMRS within the CDM group that allocated the DMRS, and The DMRS transmitted in the scheduled PDSCH is identified based on the inactive DMRS field value or the active DMRS field value and the specific antenna port value indicated by the DCI.

9. A method performed by a base station in a wireless communication system, the method comprising: Identify the DMRS ports that do not transmit demodulation reference signals (DMRS) but transmit data signals; and Sending at least one of the following to the user equipment: downlink control information (DCI), media access control (MAC) control element (CE), and radio resource control (RRC) signaling, including demodulation reference signal (DMRS) allocation information and scheduling information. The DMRS allocation information is used by the user equipment to identify the data signals for the Physical Downlink Shared Channel (PDSCH) and the DMRS ports allocated to the DMRS.

10. The method according to claim 9, wherein, The DMRS allocation information includes a DMRS null indicator, and The DMRS empty indicator indicates the reuse of a DMRS port channel that was previously allocated for PDSCH transmission.

11. The method according to claim 9, wherein, The DMRS allocation information includes at least one of an inactive DMRS field value and an active DMRS field value. The inactive DMRS field value indicates information about code division multiplexing (CDM) groups that do not transmit DMRS within the CDM groups that allocate DMRS. The activated DMRS field value indicates information about the CDM group that sent the DMRS within the CDM group that allocated the DMRS, and The DMRS transmitted in the scheduled PDSCH is associated with the inactive DMRS field value or the active DMRS field value and the specific antenna port value indicated by the DCI.

12. The method according to claim 9, wherein, The DMRS allocation information includes an interference reuse field value, and The interference reuse field value includes information about the CDM group that is valid in the second time slot and the interference information in the first time slot.

13. The method of claim 9, comprising: The DMRS port switching mode information is sent to the user equipment via the RRC signaling; and The DMRS port switching mode information is sent to the user equipment via DCI or MAC-CE. The DMRS allocation information includes information indicating the DMRS port switching mode. Specifically, the information indicating the DMRS port switching mode is used by the user equipment to identify, from the DMRS port switching mode information, the DMRS port switching mode mapped to the information indicating the DMRS switching mode. The DMRS port switching mode information includes multiple switching modes indicating inactive or active DMRS information in multiple time slots.

14. A base station in a wireless communication system, comprising: transceiver; and A controller coupled to the transceiver The controller is configured as follows: Identify the DMRS ports that do not transmit a demodulation reference signal (DMRS) but do transmit data signals; and Sending at least one of the following to the user equipment: downlink control information (DCI), media access control (MAC) control element (CE), and radio resource control (RRC) signaling, including demodulation reference signal (DMRS) allocation information and scheduling information; The DMRS allocation information is used by the user equipment to identify the data signals for the Physical Downlink Shared Channel (PDSCH) and the DMRS ports allocated to the DMRS.

15. The base station according to claim 14, wherein, The DMRS allocation information includes a DMRS null indicator, and The DMRS empty indicator indicates the reuse of a DMRS port channel that was previously allocated for PDSCH transmission.

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