Method and apparatus for configuring demodulation reference signal location in a wireless cellular communication system

Abstract

The present disclosure relates to a communication method and system for aggregating a fifth generation (5G) communication system for supporting higher data rates beyond a fourth generation (4G) system with a technology for the Internet of Things (IoT). The present disclosure can be applied to smart services based on 5G communication technology and technologies related to IoT, such as smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, security and safety services. A method for a terminal in a wireless communication system is provided. The method includes identifying a slot type of a terminal from a first slot type and a second slot type, determining a position of a demodulation reference signal (DMRS) based on the slot type, and receiving the DMRS from a base station based on the determined position.

Description

[0001] This application is a divisional application of a patent application with an application date of April 25, 2018, application number 201880027711.4, and invention name “Method and device for configuring demodulation reference signal position in a wireless cellular communication system”. Technical Field

[0002] The present disclosure relates to wireless communication systems and more particularly to methods and devices for configuring and indicating the location of a demodulation reference signal (DMRS). Background Art

[0003] In order to meet the needs of wireless data services that have increased due to the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called 'super 4G networks' or 'post-LTE systems'. 5G communication systems are considered to be implemented in higher frequency bands (mmWave), such as 60GHz bands, to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technology are discussed in 5G communication systems. In addition, in 5G communication systems, the development of system network improvements is being carried out based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communications, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiving-end interference elimination, etc. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coding modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0004] The Internet, as a human-centered connectivity network where humans generate and consume information, has now developed into the Internet of Things (IoT), in which distributed entities such as objects exchange and process data without human intervention. The Internet of Everything (IoE), which is a combination of IoT technology and big data processing technology through connection with a cloud server, has emerged. Since technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology" and "security technology" are required for IoT implementation, sensor networks, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied recently. This IoT environment can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated among connected objects. IoT can be applied to various fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart appliances and advanced medical services through aggregation and combination between existing information technology (IT) and various industrial applications.

[0005] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine type communications (MTC), and machine-to-machine (M2M) communications can be implemented through beamforming, MIMO, and array antennas. It can also be considered that the application of a cloud radio access network (RAN) as the above-mentioned big data processing technology is an example of the convergence between 5G technology and IoT technology.

[0006] On the other hand, there is a need for a method of efficiently transmitting a demodulation reference signal (DMRS) in various time slot structures in a 5G wireless communication system.

[0007] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination is made, and no assertion is made, as to whether any of the above may be applicable as prior art with respect to the present disclosure. Summary of the invention

[0008] Technical issues

[0009] In a wireless communication system, in order for a terminal to estimate a channel, a base station (BS) should send a reference signal. The terminal can use the reference signal to perform channel estimation, and can demodulate the received signal. In addition, the terminal can grasp the channel state, and can use the channel state to give feedback to the BS. In the fifth generation (5G) wireless communication, unlike the long term evolution (LTE) system, the front loaded demodulation reference signal (DMRS) has been considered as a method for minimizing delay by shortening the time required for data demodulation via fast channel estimation. In addition, because the 5G wireless communication system supports various time slot structures, there is a need for a method for configuring and indicating the position of the front loaded DMRS. In this case, the position of the front loaded DMRS exerts a large influence on the delay. On the contrary, if the position of the front loaded DMRS is dynamically changed according to the situation to minimize the delay, it becomes difficult to manage the DMRS interference in the synchronization network.

[0010] Technical Solution

[0011] Aspects of the present disclosure are to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Therefore, one aspect of the present disclosure is to provide an efficient method for configuring DMRS positions in various slot structures.

[0012] According to one aspect of the present disclosure, a method of a terminal is provided, comprising identifying a time slot type of the terminal from a first time slot type and a second time slot type, determining a position of a DMRS based on the time slot type, and receiving a DMRS from a base station based on the determined position.

[0013] According to another aspect of the present disclosure, a terminal is provided. The terminal includes a transceiver configured to send and receive signals, and at least one processor configured to identify a time slot type of the terminal from a first time slot type and a second time slot type, determine a position of a demodulation reference signal (DMRS) based on the time slot type, and control the transceiver to receive the DMRS from a base station based on the determined position.

[0014] According to another aspect of the present disclosure, a method of a BS is provided. The method includes transmitting a DMRS to a terminal at a position in a time domain, wherein a slot type of the terminal is identified from a first slot type and a second slot type, and the terminal determines the position of the DMRS based on the slot type.

[0015] According to another aspect of the present disclosure, a BS is provided. The BS includes: a transceiver configured to send and receive signals; and at least one processor configured to control the transceiver to send a DMRS at a position of the DMRS, wherein a time slot type of a terminal is identified from a first time slot type and a second time slot type, and the position of the DMRS is determined by the terminal based on the time slot type.

[0016] Technical Effects

[0017] As described above, the present disclosure relates to a method and apparatus for configuring and indicating the location of a DMRS. Because a 5G wireless communication system supports various time slot structures, there is a need for a method for configuring and indicating the location of a front-loaded DMRS. By providing a method, the DMRS location can be effectively configured in various time slot structures, and thus efficient transmission of radio resources becomes possible.

[0018] For those skilled in the art, other aspects, advantages, and salient features of the present disclosure will become apparent from the following detailed description, which, in conjunction with the accompanying drawings, discloses various embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 is a diagram illustrating a basic structure of a time-frequency domain as a radio resource region in which data or a control channel is transmitted on a downlink (DL) in a Long Term Evolution (LTE) / LTE-Advanced (LTE-A) system according to an embodiment of the present disclosure;

[0021] Figure 2 is a diagram illustrating a basic structure of a time-frequency domain as a radio resource region in which data or a control channel is transmitted on an uplink (UL) in an LTE / LTE-A system according to an embodiment of the present disclosure;

[0022] Figure 3 is a diagram illustrating radio resources of 1 resource block (RB) as a minimum unit that can be DL scheduled in an LTE / LTE-A system according to an embodiment of the present disclosure;

[0023] Figure 4 is a diagram illustrating a DL center / DL only / UL center / UL only structure as a supportable slot structure in a fifth generation (5G) new radio (NR) system according to an embodiment of the present disclosure;

[0024] Figure 5 is a diagram illustrating a location of a front-loaded demodulation reference signal (DMRS) if a slot length corresponds to 7 or 14 orthogonal frequency division multiplexing (OFDM) symbols according to an embodiment of the present disclosure;

[0025] Fig. 6A , Figure 6B and Figure 6C is a diagram illustrating a location where one additional extended / additional DMRS is transmitted in case of 14 OFDM symbols according to various embodiments of the present disclosure;

[0026] Fig. 7A , Figure 7B and Figure 7C is a diagram illustrating a DMRS pattern according to various embodiments of the present disclosure;

[0027] Figure 8 is a diagram illustrating a position of a front-loaded DMRS if the length of a basic slot is configured as y=6 or y=12 with respect to an extended cyclic prefix (CP) (ECP) in a case where a subcarrier spacing is 60 kHz according to an embodiment of the present disclosure;

[0028] Fig. 9 is a diagram illustrating the location of a DMRS according to an embodiment of the present disclosure;

[0029] Fig.10 is a diagram for explaining a method for configuring a DMRS position through a data start position indicator according to an embodiment of the present disclosure;

[0030] Fig.11 is a diagram explaining a method of configuring a DMRS position through a control format indicator (CFI) and a slot symbol duration according to an embodiment of the present disclosure;

[0031] Fig.12 is a diagram illustrating a basic slot structure in which DL and UL exist simultaneously according to an embodiment of the present disclosure;

[0032] Fig.13 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure; and

[0033] Fig.14 is a block diagram illustrating an internal structure of a base station according to an embodiment of the present disclosure.

[0034] Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. DETAILED DESCRIPTION

[0035] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in understanding but they are considered to be exemplary only. Therefore, one of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein may be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures may be omitted for clarity and conciseness.

[0036] The terms and words used in the following specification and claims are not limited to the literal meanings, but are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Therefore, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0037] It will be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

[0038] Wireless communication systems were originally developed for the purpose of providing voice-oriented services, but wireless communication systems have been expanded to broadband wireless communication systems that provide high-speed and high-quality packet data services, such as 3rd Generation Partnership Project (3GPP) High Speed ​​Packet Access (HSPA), Long Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access (E-UTRA), Advanced LTE (LTE-A), 3GPP2 High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE 802.16e communication standards. In addition, as a 5th generation wireless communication system, a fifth generation (5G) or new radio (NR) communication standard has been made.

[0039] In the LTE system, which is a representative example of a broadband wireless communication system, the downlink (DL) adopts an orthogonal frequency division multiplexing (OFDM) scheme, and the uplink (UL) adopts a single carrier frequency division multiple access (SC-FDMA) scheme. UL refers to a radio link in which a terminal (or user equipment (UE)) or a mobile station (MS) sends data or a control signal to a base station (BS) (or an evolved Node B (eNB)), and DL refers to a radio link in which the BS sends data or a control signal to the terminal. According to the above-mentioned multiple access scheme, data or control information of each user can be distinguished from each other by performing allocation and operation, thereby preventing time-frequency resources used to carry data or control information of each user from overlapping each other, that is, establishing orthogonality.

[0040] Figure 1 is a diagram illustrating a basic structure of a time-frequency domain as a radio resource region in which data or a control channel is transmitted on DL in an LTE / LTE-A system according to an embodiment of the present disclosure.

[0041] refer to Figure 1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. In the time domain, the minimum transmission unit is an OFDM symbol, and Nsymb OFDM symbols 102 constitute a time slot 106, and two time slots constitute a subframe 105. The length of the time slot is 0.5 milliseconds, and the length of the subframe is 1.0 milliseconds. In addition, a radio frame 114 is a time domain region consisting of 10 subframes. In the frequency domain, the minimum transmission unit is a subcarrier, and the transmission bandwidth (BW) of the entire system is composed of a total of N BW The number of subcarriers is 104.

[0042] In the time-frequency domain, the basic unit of resources is a resource element (RE) 112 which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB) (or physical RB (PRB)) 108 consists of Nsymb consecutive OFDM symbols 102 in the time domain and N in the frequency domain. RB Thus, one RB 108 is defined by Nsymb×N RB In general, the minimum data transmission unit is the RB unit. In the LTE system, Nsymb = 7, N RB =12, and N BW and N RB Proportional to the bandwidth of the system transmission segment. The data rate increases in proportion to the number of RBs scheduled to the terminal. The LTE system can define and operate 6 transmission bandwidths. In the case of an FDD system that operates to distinguish between DL and UL by frequency, the DL transmission bandwidth and the UL transmission bandwidth may be different from each other. The channel bandwidth represents the RF bandwidth corresponding to the system transmission bandwidth. The following Table 1 shows the correspondence between the system transmission bandwidth and the channel bandwidth defined by the LTE system. For example, an LTE system with a channel bandwidth of 10 MHz has a transmission bandwidth consisting of 50 RBs.

[0043] Table 1

[0044]

[0045] Figure 2 is a diagram illustrating a basic structure of a time-frequency domain as a radio resource region in which data or a control channel is transmitted on UL in an LTE / LTE-A system according to an embodiment of the present disclosure.

[0046] refer to Figure 2 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. In the time domain, the minimum transmission unit is the SC-FDMA symbol 202, and NsymbUL SC-FDMA symbols can constitute a time slot 206. In addition, two time slots constitute a subframe 205. In the frequency domain, the minimum transmission unit is the subcarrier, and the transmission bandwidth 204 of the entire system consists of a total of NBW subcarriers. BW can have a value proportional to the system transmission bandwidth. Figure 1 The subcarrier 110 of the radio frame 214 corresponds to Figure 1 Radio frame 114.

[0047] In the time-frequency domain, the basic unit of resources is RE 212 which can be defined by SC-FDMA symbol index and subcarrier index. RB pair 208 is defined by NsymbUL consecutive SC-FDMA symbols in the time domain and NscRB consecutive subcarriers in the frequency domain. Therefore, one RB can be composed of NsymbUL×NscRB REs. In general, the minimum transmission unit of data or control information is RB unit. PUCCH is mapped to the frequency domain corresponding to 1RB and is transmitted in one subframe.

[0048] Figure 3 1 RB is a diagram illustrating a radio resource of 1 RB as a minimum unit that can be DL-scheduled in an LTE / LTE-A system according to an embodiment of the present disclosure. Figure 3 On the radio resources shown, different types of signals may be sent as follows.

[0049] 1. Cell-specific Reference Signal (RS) (CRS): It is a reference signal periodically transmitted to all terminals belonging to one cell and can be commonly used by a plurality of terminals.

[0050] 2. Demodulation Reference Signal (DMRS): It is a reference signal sent for a specific terminal and is sent only when data is transmitted to the corresponding terminal. DMRS can be composed of a total of 8 DMRS ports. In LTE / LTE-A, ports 7 to 14 correspond to DMRS ports, and the ports use CDM or FDM to maintain orthogonality so that no interference occurs between ports.

[0051] 3. Physical DL Shared Channel (PDSCH): It is a data channel transmitted to DL and is used by the BS to transmit traffic to the terminal. It is transmitted using REs, thus Figure 2 No reference signal is sent in the data region.

[0052] 4. Channel State Information Reference Signal (CSI-RS): It is a reference signal transmitted to a terminal belonging to one cell and is used to measure the channel state. Multiple CSI-RS can be transmitted to one cell.

[0053] 5. Other channels (Physical Hybrid Automatic Repeat Request (ARQ) Indicator Channel (PHICH), Physical Control Format Indicator Channel (PCFICH), and Physical Downlink Control Channel (PDCCH)): They are used to provide control information required for the terminal to receive PDSCH, or send acknowledgement / non-acknowledgement (ACK / NACK) to operate hybrid ARQ (HARQ) for UL data transmission.

[0054] In the case of DMRS among the above signals, Figure 3 As shown, the position of DMRS is fixed. However, unlike the LTE system, various time slot structures are supported in 5G wireless communication, and therefore the position of DMRS can be configured unfixedly. More specifically, according to the 3GPP RAN1#_86bis protocol, the time slot of the 5G NR communication system is defined as follows.

[0055] • For subcarrier spacing (SCS) up to 60kHz with Null Cyclic Prefix (NCP), y=7 and 14

[0056] ■ For further study (FFS): whether / which down-select is selected for one or more SCSs

[0057] For SCS above 60kHz with NCP, y=14

[0058] Here, y represents the slot length represented by the number of OFDM symbols. In the protocol, the slot length y can be basically defined to include all possible DL center / DL only / UL center / UL only structures in the 5G NR communication system.

[0059] Figure 4 2 is a diagram illustrating a DL center / DL only / UL center / UL only structure as a supportable time slot structure in a 5G NR system according to an embodiment of the present disclosure.

[0060] refer to Figure 4 , 410, 420, 430 and 440 represent the time slot structure that can be supported in the 5G NR system, and illustrate each DL center / DL only / UL center / UL only structure. In 410 and 430, the guard period (GP) is the time required during the DL-UL transition, and the required length may vary depending on the cell coverage or propagation delay. In addition, according to the 3GPP RAN1#_88bis protocol, the time slot of the 5G NR communication system is defined as follows.

[0061] ● Specification supports minimum duration of 1 OFDM symbol with data and data channels starting at any OFDM symbol except above 6GHz to below 6GHz

[0062] ■ Note: This may not apply to all types of UEs and / or use cases

[0063] ■ It may not be desirable for UE to blindly detect the presence of DMRS or PT-RS

[0064] ■FFS: Whether 1-symbol data puncturing can be indicated by preemption indication

[0065] According to the protocol, the time slot length of the 5G NR communication system can correspond to 1 to 14 OFDM symbols. Because various time slot structures are supported in 5G wireless communication as described above, a specific operation method for this is required. For example, in the case of y=14, the time slot is defined by a basic time slot and can be defined as a time slot structure supportable for all UEs. In addition, in the case of y less than 14, the time slot is defined by a mini time slot and can be defined as a time slot structure for specific use cases, such as ultra-reliable low-latency communication (URLLC).

[0066] In addition, in 5G wireless communication, front-loaded DMRS has been considered as a method for minimizing delay by shortening the time required for data demodulation through fast channel estimation. More specifically, according to the 3GPP RAN1#_88 protocol, the front-loaded DMRS of the 5G NR communication system is defined as follows.

[0067] ● The front-loaded DMRS is mapped across 1 or 2 adjacent OFDM symbols

[0068] ■NR performance at least comparable to LTE’s DM-RS in scenarios applicable to both LTE and NR

[0069] In addition, according to the 3GPP RAN1#_88bis protocol, the front-load DMRS of the 5G NR communication system can be defined as follows.

[0070] ● At least for a time slot, the position of the front-loaded DLDMRS is fixed regardless of the first symbol position of the PDSCH

[0071] ■FFS: Mini-slot situation

[0072] According to the protocol, the front-loaded DMRS consists of one or two adjacent OFDM symbols, and in the basic slot structure, the position of the front-loaded DMRS is fixed regardless of the starting position of the PDSCH. However, in the mini slot, it is not determined whether the position of the front-loaded DMRS is fixedly configured or dynamically changed. According to the 3GPP RAN1 discussion of the current NR system, it is noted that the precise definition of the time slot has not yet been made. Therefore, the wording of the basic time slot and the mini slot cannot be defined separately. However, based on the following protocol, an explanation can be made for the assumption that the case corresponding to the following description is called the basic time slot, and the case not corresponding to the following description is called the non-basic time slot.

[0073] • For SCS up to 60kHz with NCP, y=7 and 14

[0074] ■FFS: whether / which down selection is made for one or more SCSs

[0075] For SCS above 60kHz with NCP, y=14

[0076] Based on the assumptions described above, the basic time slot can be used as a basic structure that can be supported by all UEs. If it is taken into account that the synchronous network dynamically changes the position of the DMRS, it becomes difficult to manage DMRS interference. According to the current protocol, the position of the front-loaded DMRS is fixed regardless of the starting position of the PDSCH. If the position of the front-loaded DMRS is fixed, the DMRS cannot be located on the front side despite the short PDCCH area, and is therefore inefficient for the purpose of delay minimization. However, in the case of a non-basic time slot, it has a time slot structure used in a specific use case, and considering the synchronous network, there is no great motivation to configure the position of the DMRS fixedly, regardless of the starting position of the PDSCH. It is quite beneficial to shorten the time required for data demodulation via channel estimation by maximally positioning the front-loaded DMRS on the front side. Therefore, the present disclosure provides a method for effectively configuring the DMRS position for various time slot structures supported in a 5G wireless communication system.

[0077] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although embodiments of the present disclosure are described in the state of an example LTE or LTE-A system, embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, the fifth generation mobile communication technology (5G and NR) developed after LTE-A may be included therein. More specifically, the basic structure of the time-frequency domain in which signals are transmitted on DL and UL may be different from Figure 1 and Figure 2As shown. In addition, different types of signals can be sent on DL and UL. Therefore, the embodiments of the present disclosure can also be applied to other communication systems by partial modifications within the scope that does not significantly deviate from the scope of the present disclosure at the discretion of those skilled in the art.

[0078] In addition, when describing the present disclosure, if it is determined that the specific description of the relevant function or configuration will obscure the subject of the present disclosure with unnecessary details, the specific description of the relevant function or configuration will be omitted. In addition, all the terms to be described later are terms that take into account the functional definition of the present disclosure, and may be different depending on the intention of the user or operator or customer. Therefore, they should be defined based on the content of the entire description of the present disclosure. In the following, BS is a subject that performs resource allocation to the terminal, and may be at least one of an eNB, a node B, a BS, a radio connection unit, a BS controller, and a node on the network. The terminal may include a UE, an MS, a cellular phone, a smart phone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, DL is a radio transmission path for a signal sent from a BS to a terminal, and UL refers to a radio transmission path for a signal sent from a terminal to a BS.

[0079] In the following, the DMRS to be described is a reference signal that is transmitted by UE-specific precoding and has a feature that the UE can demodulate the signal even without additionally received precoding information, and uses the same name as that used in the LTE system. However, depending on the intention of the user of the reference signal and the purpose of use, the term "DMRS" may be represented by another term. For example, it may be represented by another term, such as UE-specific RS or dedicated RS. More specifically, the term "DMRS" is presented only as a specific example for easily explaining the technical content of the present disclosure and to help understand the present disclosure, and it is obvious to those skilled in the art to which the present disclosure belongs that the above-mentioned operations may be specifically expressed by other terms based on the technical concepts of the present disclosure.

[0080] In the first embodiment of the present disclosure to be described below, a method for determining a DMRS position in a basic time slot structure in which only DL or UL exists will be described. In the second embodiment, a method for determining a DMRS position for a basic time slot structure in which only DL or UL exists will be described. In the third embodiment, a method for determining a DMRS position for a non-basic time slot structure in which only DL or UL exists will be described. In the fourth embodiment, a method for determining a DMRS position for a basic time slot structure in which DL and UL exist simultaneously will be described.

[0081] <First Embodiment>

[0082] In the first embodiment, a method for determining the DMRS position in the basic time slot structure where only DL or UL exists will be described. As described above, according to the 3GPP RAN1 discussion of the current NR system, the precise definition of the time slot has not yet been made. In the first embodiment, the following is defined as the basic time slot based on the 3GPP RAN1#_86bis protocol.

[0083] • For SCS up to 60kHz with NCP, y=7 and 14

[0084] ■FFS: whether / which down selection is made for one or more SCSs

[0085] For SCS above 60kHz with NCP, y=14

[0086] Therefore, for the case where the subcarrier spacing is equal to or less than 60kHz, the length of the basic time slot can be configured as y=7 or y=14. In addition, relative to the case where the subcarrier spacing is greater than 60kHz, the length of the basic time slot can be configured as y=14. Therefore, in a first embodiment, a method is provided for determining the DMRS position for the basic time slot structure for a subframe in which only DL exists by defining the time slot structure. First, for a subframe in which only DL exists, the DMRS position in the basic time slot structure can be determined by the area occupied by the control channel area. The control format indicator (CFI) is used to indicate how many OFDM symbols the control channel consists of. In a 5G communication system, the CFI can be configured in the following way.

[0087] ●Alt-1: Radio Resource Control (RRC) Configuration

[0088] ●Alt-2: Configuration via group common downlink control information (DCI)

[0089] Alt-1 is a method for semi-statically configuring CFI information, and Alt-2 is a method for dynamically configuring CFI information similar to the LTE system. In the 5G communication system, CFI information can be configured in the above method. In addition, the DMRS position in the basic time slot structure of the subframe in which only DL exists can be configured as follows by the configured CFI.

[0090]

Mathematical diagram 1

[0091] Max(CFI)+1

[0092] The method for configuring the DMRS position according to Mathematical Formula 1 has the feature that the DMRS position is fixed regardless of the starting position of the PDSCH. In a 5G communication system, multiple DMRS structures can be configured. As an example for this, the configurable DMRS structure can be divided into a front-load DMRS and an extended / additional DMRS. In particular, the front-load DMRS is a DMRS located on the front side of the NR-PDSCH for fast data decoding, and can be composed of one or two adjacent OFDM symbols. Therefore, Mathematical Formula 1 can indicate the position of the front-load DMRS.

[0093] Figure 5 is a diagram illustrating the position of a front-loaded DMRS if a slot length corresponds to 7 or 14 OFDM symbols according to an embodiment of the present disclosure.

[0094] Here, the position configuration of the front-load DMRS can be determined by the control channel area. If the maximum CFI is 2, the front-load DMRS is located at the third OFDM symbol, as shown in 510. If the maximum CFI is 3, the front-load DMRS is located at the fourth OFDM symbol, as shown in 520. If the position of the front-load DMRS is determined by the control channel area that can be configured to the maximum, there may be a loss in reducing the decoding delay due to the DMRS position that is always configured at a fixed position when part or all of the control channel is not configured. Therefore, in the present disclosure, as an extended method, a method capable of configuring the position of another front-load DMRS is provided. For example, if the maximum CFI is 2, in addition to the configuration for fixing the front-load DMRS to the third OFDM symbol as shown in 510, an option for fixing the front-load DMRS to the first OFDM symbol as shown in 530 can be configured. In addition, depending on the situation, if two options are configured, the disadvantages of fixing the position of the front-load DMRS can be improved. In particular, there may be various methods for configuring the position of one or more front-load DMRS. For example, a method for semi-statically configuring the position of the front-load DMRS through upper layer signaling such as RRC may be considered. As another method, the position of the front-load DMRS may be configured in system information such as a master information block (MIB) or a system information block (SIB). In addition, a method for dynamically configuring the position of the front-load DMRS through a medium access control (MAC) control element (CE) or DCI. Different from this, the position of the front-load DMRS may also be configured through semi-persistent scheduling (SPS).

[0095] Next, the extended / additional DMRS will be described. According to the front-loaded DMRS as described above, it is not possible to track the fast time-changing channel under high Doppler conditions, and it is difficult to accurately estimate the channel. In addition, it is not possible to perform frequency offset correction only with the front-loaded DMRS. For this reason, it is necessary to send the additional DMRS after the position of the front-loaded DMRS is sent in the time slot.

[0096] Fig. 6A , Figure 6B and Figure 6C is a diagram illustrating a position at which one additional extended / additional DMRS is transmitted in case of 14 OFDM symbols according to various embodiments of the present disclosure.

[0097] First, in the case of 14 OFDM symbols, by Fig. 6A , Figure 6B and Figure 6C 610, 620, 630 and 640 illustrate each location where an additional extended / additional DMRS is transmitted. FIG. 6A to FIG. 6C , it is considered that the configuration is Figure 5 The maximum 2 DL control regions of 510 in the scheme are considered, and considering that OFDM symbol positions 12 and 13 can be used for GP and UL in a time slot structure in which DL and UL exist simultaneously, OFDM symbol positions 12 and 13 are excluded from the candidates. In addition, through experiments, the throughput performance diagram for 610 to 640 is shown as 650. As a result of the experiment, it can be observed that the performance is improved because an additional extended / additional DMRS is subsequently sent. Based on this, if an extended / additional DMRS is added, it can be a good replacement for 640 in terms of throughput performance. However, because the DMRS is located at the back, the time required for data demodulation is shortened by fast channel estimation, and this can lead to disadvantages in terms of delay minimization. Therefore, considering the throughput performance and delay based on the experimental results, the following options can be considered.

[0098] ●Alt-1: 610-Prioritize delay.

[0099] ●Alt-2: 640-prioritizes throughput.

[0100] ●Alt-3: 620—Consider the tradeoff between throughput and latency.

[0101] In the case of Alt-3, if the structure of 620 is selected by 660, the relative throughput is reduced to 103% or less compared to 640, and the position is configured to avoid the position where the CRS is sent in the LTE system. Therefore, under the LTE-NR coexistence condition, it has the advantage of anti-interference. In addition, Alt-3 can be a good replacement for configuring a DMRS position that is not different from the time slot structure considered in the second embodiment below. If the time slot length corresponds to 14 OFDM symbols, then according to the Doppler condition. Two or more extended / additional DMRS positions are required. For example, in a fast channel change environment in which the subcarrier spacing is kHz, 4 extended / additional DMRS positions need to be configured, such as 670. Considering the time slot structure in which DL and UL exist simultaneously and DMRS is positioned symmetrically to the greatest extent, the DMRS position of 670 corresponds to a structure in which the two last symbols are cleared. In all embodiments of the present disclosure, the time position of configuring DMRS based on one OFDM symbol is illustrated. For example, it should be noted that if two adjacent OFDM symbols are required for antenna port expansion, the DMRS transmission position can be configured additionally. In addition, in the present disclosure, the DMRS pattern applied to the time position for transmitting DMRS is not limited. In the present disclosure, the time position for DMRS transmission is focused, but the DMRS pattern applied is not limited. For example, in an embodiment of the present disclosure, all or part of the REs of a DMRS transmission symbol can be used as DMRS.

[0102] Fig. 7A , Figure 7B and Figure 7C is a diagram illustrating a DMRS pattern according to various embodiments of the present disclosure.

[0103] For example, you can use FIG. 7A to FIG. 7C In addition, in the case of extended / additional DMRS, multiple DMRS are configured in time, and thus DMRS overhead issues may occur. In this case, DMRS overhead can be reduced by configuring DMRS with low frequency density. For example, FIG. 7A to FIG. 7CIn the case of 720, the high DMRS density of 710 can be considered, and more efficient transmission can be performed by configuring a DMRS with a low frequency density. More specifically, for methods 720 and 730 for configuring a DMRS with a low frequency density, the throughput performance and relative gain are illustrated in 740 and 750. As a result of the experiment, in the case of configuring extended / additional DMRS, it can be observed that the configuration of the front-load DMRS and the extended / additional DMRS at the same low frequency density as 720 shows better performance than the configuration of the front-load DMRS and the extended / additional DMRS at different frequency densities as 730. Therefore, the extended / additional DMRS can be configured to have the same density as the front-load DMRS. However, considering MU-MIMO for high-speed terminals and low-speed terminals, the present disclosure may use the following DMRS configuration method.

[0104] • The UE may assume that the density for additional DMRS is the same for the number of transmission layers less than or equal to X, and decreases otherwise.

[0105] In the above method, X represents a parameter for determining the DMRS frequency density of the front-load DMRS and the extended / additional DMRS, and can be configured as the number of transmission layers of 2 or 4. The above method is a method for enabling a low-speed terminal to perform high-level transmission, and is shown in FIG. FIG. 7A to FIG. 7C According to 760, the front-load DMRS and the extended / additional DMRS may be configured at different DMRS frequency densities.

[0106] Although DMRS positions have been provided around DL, DMRS can be configured at the same position for UL to support a common DMRS structure for DL ​​and UL. If DL and UL have a common DMRS structure, interference can be easily controlled by orthogonal DMRS port allocation between UL and DL in an environment such as dynamic TDD.

[0107] Hereinafter, a method of a BS for configuring a DMRS structure in consideration of a point at which the DMRS structure becomes diversified according to the present disclosure will be described. Note that the following method for configuring a DMRS structure may be applied to other embodiments.

[0108] Table 2

[0109]

[0110] In particular, the RS structure extended in time can be indicated by the DMRS-timeDensityId in Table 2. Here, maxDMRS-Time represents the maximum number of configurable DMRS-timeDensityIds. For example, it can be used to configure the RS structure extended in time, such as front-loaded RS and extended / additional DMRS. Finally, in Table 2, different RS frequency densities can be configured by DMRS-frequencyDensityId. Here, maxDMRS-Frequency represents the maximum configurable number of DMRS-frequencyDensityIds. For example, it can be used to configure a low RS frequency density to adjust RS overhead. It should be noted that the terminology for the field value configured in Table 2 can be replaced by another term. The terms used here are only used to present specific examples to facilitate the explanation of the technical content of the present disclosure and to help understand the purpose of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to the technicians in the field to which the present disclosure belongs that the above operations can be specifically expressed by other terms based on the technical concepts of the present disclosure. More specifically, through the above method, the DMRS structure can be semi-statically configured through RRC, and the terminal can grasp the structure of the currently transmitted DMRS through the value configured in RRC. Next, a method for dynamically configuring a BS for a DMRS structure suitable for a transmission environment will be described. If the DMRS information is configured in the MAC CE in a method similar to the method for configuring the DMRS information in the RRC, the information about the DMRS structure can be configured more dynamically. Next, the simplest method for dynamically configuring the DMRS structure is to place the information about the DMRS structure in the DCI to be transmitted. In this case, for basic operations, the DCI format to which the field for dynamically operating the DMRS structure is not applied can be separately defined. If the DMRS structure is configured using DCI, it becomes possible to dynamically change the DMRS structure. Relatively speaking, DCI overhead may occur during the operation of the DMRS structure. Because it may not be necessary to change different DMRS modes in time and frequency as fast as dynamic signaling, as in Table 2, dynamic signaling needs to cope with time-frequency channel changes, it is more preferred to configure the DMRS structure in the RRC.

[0111] <Second Embodiment>

[0112] In the second embodiment, a method for determining the DMRS position in a basic time slot structure in which only DL or UL exists will be described. In the first embodiment, it is assumed that the terminal is configured as a general CP, and in the second embodiment, it is assumed that the terminal is configured as an extended CP (ECP). If the terminal is configured as an extended CP, the following situation is defined as a basic time slot based on the 3GPP RAN1#_88bis protocol.

[0113] ● Will confirm for 60kHz ECP with WA.

[0114] ■One time slot consists of 6 or 12 OFDM symbols.

[0115] ◆ If the down-selection of NCP will occur between 7 or 14 OFDM symbols, RAN1 will also apply the down-selection of ECP between 6 or 12 OFDM symbols.

[0116] Therefore, if the subcarrier spacing is 60kHz, the length of the basic time slot for ECP can be configured as y=6 or y=12. Therefore, in the second embodiment, if the terminal is configured as an extended CP by definition of the time slot structure, a method for determining the DMRS position for the structure of the basic time slot in which only DL or UL exists is provided. In the same manner as the method provided in the first embodiment, the position of the front-loaded DMRS can be determined from Mathematical Formula 1 by the configured CFI. In addition, by additionally configuring the position of one or more front-loaded DMRS, the disadvantages of always fixing the position of the front-loaded DMRS and the possible loss in reducing decoding delay can be improved.

[0117] Figure 8 is a diagram illustrating the position of a front-loaded DMRS if the length of a basic slot is y=6 or y=12 for ECP configuration in a case where a subcarrier spacing is 60 kHz according to an embodiment of the present disclosure.

[0118] refer to Figure 8 , if the subcarrier spacing is 60kHz and the length of the basic time slot is configured as y=6 or y=12, the position diagram of the front-loaded DMRS according to mathematical diagram 1 is as follows Figure 8 810 and 820, and the configuration diagram of the position of the additional front-load DMRS is shown as 830. In addition, in the same manner as the first embodiment, it is not possible to track fast time-varying channels under high Doppler conditions. Therefore, it is difficult to accurately estimate the channel. In addition, it is not possible to perform correction of frequency offset only with the front-load DMRS. For this reason, it is necessary to send an additional DMRS after the position of the front-load DMRS is sent in the time slot. If the subcarrier spacing is 60kHz, the OFDM symbol spacing is reduced to 1 / 4 compared to the case where the subcarrier spacing is 15kHz. Therefore, it is not necessary to require two or more extended / additional DMRSs to track fast time-varying channels as in the first embodiment. Therefore, in the same manner as the first embodiment, it is considered that a maximum of 2 DL control regions are configured, and considering that the two last OFDM symbol positions 12 and 13 can be used for GP and UL in a time slot structure in which DL and UL exist simultaneously, the last two OFDM symbol positions 12 and 13 are excluded from the candidates. Based on this, the following options can be considered.

[0119] ●Alt-1: 910-Prioritize delay.

[0120] Alt-2: 920 - prioritizes throughput

[0121] Based on the results of the experiment of the first embodiment, Alt-1 may be a position where latency is prioritized, and Alt-2 may be a position where throughput is prioritized.

[0122] Although DMRS positions have been provided around DL, DMRS can be configured at the same position even for UL to support a common DMRS structure for DL ​​and UL. If DL and UL have a common DMRS structure, interference can be easily controlled by orthogonal DMRS port allocation between UL and DL in an environment such as dynamic TDD.

[0123] <Third Embodiment>

[0124] In the third embodiment, a method for determining the DMRS position in a basic slot structure in which only DL or UL exists will be described. According to the 3GPP RAN1 discussion of the current NR system, it is noted that the precise definition of the slot has not yet been made. Therefore, the terms of the basic slot and mini slot currently discussed in 3GPP RAN1 may not be defined separately. In the first embodiment, the following is defined as the basic slot based on the 3GPP RAN1#_86bis protocol.

[0125] • For SCS up to 60kHz with NCP, y=7 and 14.

[0126] ■FFS: Whether / which one to select downward for one or more SCSs.

[0127] • For SCS above 60kHz with NCP, y=14.

[0128] According to the third embodiment, for the case where the subcarrier spacing is equal to or less than 60kHz, the length of the basic time slot can be configured as y=7 or y=14. Different from this, in the case of a non-basic time slot, the time slot can be distinguished in the following method. In the NR system, the non-basic time slot can be called a mini time slot.

[0129] ●Alt-1: Distinguished by symbol length.

[0130] ●Alt-2: Distinguished by PDCCH monitoring period.

[0131] In particular, according to Alt-1, for the case where the subcarrier spacing is equal to or less than 60kHz, if the length of the basic time slot is configured as y=7, the case where the length of the basic time slot is configured as less than y=7 can be defined as a non-basic time slot. Different from this, if the length of the basic time slot is configured as y=14, the case where the length of the basic time slot is configured as less than y=14 can be defined as a non-basic time slot. In addition, for the case where the subcarrier spacing is greater than 60kHz, if the length of the time slot is configured as less than y=14, the case can be defined as a non-basic time slot. Different from this, according to Alt-2, non-basic time slots can be distinguished by the PDCCH monitoring period. For example, if the PDCCH monitoring period is configured as X in the case of a basic time slot, the case of a time slot with a PDCCH monitoring period less than X can be defined as a non-basic time slot. More specifically, if the time slot consists of one OFDM symbol, PDCCH monitoring can be performed for each OFDM symbol.

[0132] As described above, in the third embodiment, a method for determining the DMRS position of a non-basic time slot for a subframe in which only DL exists by the definition of the time slot structure is provided. In the case of a basic time slot, it can be used as a basic structure supported by all UEs. If the position of the DMRS is dynamically changed in consideration of the synchronous network, it becomes difficult to manage DMRS interference. However, if the position of the front-loaded DMRS is fixed, the DMRS cannot be located on the front side despite the short PDCCH area, and is therefore inefficient for the purpose of delay minimization. However, in the case of a non-basic time slot, such as a mini-time slot, it has a time slot structure used in a specific use case, and considering the synchronous network, it has no great motivation to configure the position of the DMRS fixedly, regardless of the starting position of the PDSCH. By maximally positioning the front-loaded DMRS on the front side, it is beneficial to shorten the time required for data demodulation via channel estimation. Therefore, in consideration of this, the present disclosure provides a method for configuring the DMRS position for a non-basic time slot for a subframe in which only DL exists as follows.

[0133] ●Alt-1: The DMRS position is determined by the data start position indicator.

[0134] ●Alt-2: The DMRS position is determined by TCFI and slot symbol duration.

[0135] Fig. 9 is a diagram illustrating the location of a DMRS according to an embodiment of the present disclosure.

[0136] In the disclosed method, Alt-1 is a method for configuring a DMRS position by a data start position indicator newly defined in a 5G NR communication system, and is a method for determining that a front-load DMRS is located at a data start position indicated by a data start position indicator. In a 5G NR communication system, the data start position indicator may be dynamically configured or semi-statically configured.

[0137] Fig.10 is a diagram for explaining a method for configuring a DMRS position by a data start position indicator according to an embodiment of the present disclosure.

[0138] More specifically, Fig.10 The Alt-1 method is described in detail. Fig.10 An example of a time slot structure consisting of 3 OFDM symbols is illustrated in FIG. 1 , and DMRS, data, and control channels are illustrated in different colors. If multiple data start position indicators can be configured in a 5G NR communication system, then Fig.10 1010 configures the position of the frontload DMRS. Because multiple data start position indicators are supported, data transmission is possible from the frontmost OFDM symbol when the control region does not exist in a specific RB, and the frontload DMRS can be located therein. Different from this, if only one data start position indicator can be configured in the 5G NR communication system, the position of the frontload DMRS can be configured as 1020. In this case, as shown in 1020, if there is no control region in a specific RB, data transmission from the frontmost OFDM symbol becomes impossible, and the position of the frontload DMRS can be configured at the data start position indicated by one data start position indicator. According to the method for configuring the data start position indicator of Alt-1, the position of the frontload DMRS can be configured dynamically or semi-statically. Different from this, Alt-2 is a method for determining the DMRS position by CFI and time slot symbol duration. More specifically, the position of the frontload DMRS can be determined by the following mathematical formula.

[0139]

Mathematical Diagram 2

[0140] Min(Max(CFI)+1,slot-duration)

[0141] In Mathematical Formula 2, the position of the front-loaded DMRS is determined by the CFI and the time slot symbol duration. In Mathematical Formula 2, the time slot duration is a value configured when the time slot length is less than max(CFI). For example, if the time slot consists of one symbol, the front-loaded DMRS is located at the first OFDM symbol regardless of the CFI. Mathematical Formula 2 can be divided into two different methods according to the CFI value. The first method is a method for determining that the CFI value is a value configured by the control resource set (CORESET). In this case, there is no need to perform signaling of additional information to the terminal for the CFI value configured in the CORESET.

[0142] Fig.11 is a diagram for explaining a method for configuring a DMRS position through a CFI and a slot symbol duration according to an embodiment of the present disclosure.

[0143] More specifically, Fig.11 The Alt-2 method is described in more detail. Fig.11 An example of a time slot structure consisting of 3 OFDM symbols is illustrated in FIG, and DMRS, data, and control channels are illustrated in different colors. In the case of the first method, since the position of the front-loaded DMRS is determined according to the CFI configured in the CORESET, the DMRS position can be configured as close to the control channel as possible. Fig.11As shown in 1110 and 1120, 1110 illustrates the DMRS configuration position according to the first method when the CFI value configured in the CORESET is 2, and 1120 illustrates the DMRS configuration position when the CFI value configured in the CORESET is 1. If the DMRS can be located at a further front side through PDSCH start position information or additional configured signaling, as shown in 1130 and 1140, the DMRS position is configured at a further front side to further minimize the delay. In this case, the DMRS position can be determined by the granularity of the data start position on the frequency axis. For example, by configuring the DMRS position in units of resource block groups (RBGs), multiple RBGs, bandwidth parts (subbands), or PRB levels, data scheduling and DMRS channel estimation can be operated more efficiently. The second method using mathematical formula 2 is determined considering all configurable values ​​for the CFI value. In the case of using this method, even for non-basic time slots, the position of the front-loaded DMRS can be fixed regardless of the starting position of the PDSCH. For example, as shown in 1150 and 1160, when the CFI value of the 1150 region is 2 and the CFI value of the 1120 region is 1, the position of the front-loaded DMRS can be determined as the third OFDM symbol considering the maximum value of the two values. In the case of the disclosed Alt-2, the DMRS position is determined by the maximum value of the CFI, and thus the frequency of the DMRS position change may be small. As described above in the first embodiment, if the CFI information is semi-statically configured, the frequency of the DMRS position change may become smaller.

[0144] Although DMRS positions have been provided around DL, DMRS can be configured even at the same position as UL to support a common DMRS structure for DL ​​and UL. If DL and UL have a common DMRS structure, interference can be easily controlled by orthogonal DMRS port allocation between UL and DL in an environment such as dynamic TDD.

[0145] <Fourth Embodiment>

[0146] In the fourth embodiment, a method for determining a DMRS position in a basic slot structure in which DL and UL exist simultaneously will be described. In the first embodiment, the following is defined as a basic slot based on the 3GPP RAN1#_86bis protocol.

[0147] • For SCS up to 60kHz with NCP, y=7 and 14.

[0148] ■FFS: Whether / which one to select downward for one or more SCSs.

[0149] • For SCS above 60kHz with NCP, y=14.

[0150] According to the first embodiment, for the case where the subcarrier spacing is equal to or less than 60kHz, the length of the basic time slot can be configured as y=7 or y=14. In addition, for the case where the subcarrier spacing is greater than 60kHz, the length of the basic time slot can be configured as y=14. According to the protocol, the time slot length y can be defined to include substantially all possible DL center / DL only / UL center / UL only structures in the 5G NR communication system. Therefore, in the DL center or UL center structure in which DL and UL exist simultaneously, the DMRS position can be configured differently from the DL only or UL only structure due to the DL / UL symbol length and GP influence. For the same reason, in a fourth embodiment, a method for determining the DMRS position for a basic time slot structure in which DL and UL exist simultaneously is provided.

[0151] Fig.12 is a diagram illustrating a basic slot structure in which DL and UL exist simultaneously according to an embodiment of the present disclosure.

[0152] More specifically, Fig.12 The basic time slot structure 1210 in which DL and UL exist simultaneously is shown. Fig.12 , DL, GP and UL are illustrated in different colors. In this case, the position of the frontload DMRS can be configured in the same method as the method of mathematical diagram 1 according to the first embodiment, or can be configured by mathematical diagram 2 according to the third embodiment. In the first, second and third embodiments, the UL DMRS position can be configured at the same position as the position of the DL DMRS under the assumption of a DL-only or UL-only structure. However, in a DL-centered or UL-centered structure in which DL and UL exist simultaneously, the areas occupied by DL / GP / UL may be different from each other, and therefore such a configuration may be difficult. Therefore, it is proposed to determine the position of the frontload DMRS for UL based on GP as in the following mathematical diagram.

[0153]

Mathematical Diagram 3

[0154] Last symbol position for GP+1

[0155] According to mathematical diagram 3, Fig.12 The “last symbol position for GP” in GP becomes 8, and the position of the frontload DMRS for UL can start from 9.

[0156] In order to implement the above-mentioned embodiments of the present disclosure, Fig.13 and Fig.14The transmitter, receiver and processor of the terminal or BS are illustrated in FIG. According to the first to fourth embodiments, the method for configuring the DMRS position and the transmission / reception method between the BS and the terminal are described, and for this, the receiver, processor and transmitter of the BS or the terminal should operate according to each embodiment.

[0157] Fig.13 is a block diagram illustrating an internal structure of a terminal according to an embodiment of the present disclosure.

[0158] refer to Fig.13 , according to the present disclosure, the terminal may include a terminal receiver 1300, a terminal transmitter 1304, and a terminal processor 1302. In an embodiment of the present disclosure, the terminal receiver 1300 and the terminal transmitter 1304 may be collectively referred to as a transceiver. The transceiver may send / receive signals with the BS. The signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplification and down-converting the frequency of the received signal. In addition, the transceiver may receive a signal through a radio channel, and may output the received signal to the terminal processor 1302. The transceiver may also send a signal output from the terminal processor 1302 through a radio channel. The terminal processor 1302 may control a series of processes for terminal operation according to the above-mentioned embodiment of the present disclosure. For example, the terminal receiver 1300 may receive a reference signal from the BS, and the terminal processor 1302 may be controlled to analyze a method for applying a reference signal. In addition, the terminal transmitter 1304 may also send a reference signal.

[0159] Fig.14 is a block diagram illustrating an internal structure of a BS according to an embodiment of the present disclosure.

[0160] refer to Fig.14, the BS according to the embodiment of the present disclosure may include a BS receiver 1401, a BS transmitter 1405, and a BS processor 1403. In the embodiment of the present disclosure, the BS receiver 1401 and the BS transmitter 1405 may be collectively referred to as a transceiver. The transceiver may send / receive signals with the terminal. The signal may include control information and data. To this end, the transceiver may be composed of an RF transmitter for up-converting and amplifying the frequency of the transmitted signal, and an RF receiver for low-noise amplification and down-converting the frequency of the received signal. In addition, the transceiver may receive a signal through a radio channel, and may output the received signal to the BS processor 1403. The transceiver may also send a signal output from the BS processor 1403 through a radio channel. The BS processor 1403 may control a series of processes for BS operation according to the above-mentioned embodiment. For example, the BS processor 1403 may control to determine the structure of the reference signal and generate configuration information for the reference signal to be transmitted to the terminal. Thereafter, the BS transmitter 1405 may transmit the reference signal and the configuration information to the terminal, and the BS receiver 1401 may also receive the reference signal.

[0161] In addition, according to an embodiment of the present disclosure, the BS processor 1403 may process the DMRS position configuration. In addition, the BS transmitter 1405 may transmit this required information to the terminal.

[0162] While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims and their equivalents.

Claims

1. A method performed by a base station in a wireless communication system, the method comprising: Sending a master information block MIB on a physical broadcast channel PBCH, the MIB comprising information about a position of a first demodulation reference signal DMRS for a first time slot type; identifying a time slot type from a first time slot type and a second time slot type; In a case where the identified time slot type is the first time slot type, transmitting a first DMRS on one of a third symbol or a fourth symbol of the time slot in a downlink based on the MIB; as well as In case the identified time slot type is the second time slot type, a first DMRS is transmitted on a first symbol of the scheduled downlink data resource.

2. The method according to claim 1, wherein: Sending a first DMRS on a first symbol of the scheduled downlink data resource further comprises: In case the identified slot type is the second slot type and the physical downlink shared channel PDSCH allocation conflicts with resources reserved for the control region resources CORESET, a first DMRS is transmitted on a first symbol after the CORESET.

3. The method according to claim 1, further comprising: Sending information about additional DMRS for downlink in higher layer signaling; In case three additional DMRSs for downlink are configured by higher layer signaling, the additional DMRSs are transmitted on the sixth symbol, the ninth symbol and the twelfth symbol of a time slot having a duration of 14 symbols.

4. The method according to claim 1, further comprising: receiving a first DMRS from a terminal in an uplink, Wherein, in the case where the time slot type is the first time slot type, the position of the first DMRS used in the uplink is determined based on the MIB on one of the third symbol or the fourth symbol of the time slot.

5. The method according to claim 4, further comprising: Sending information about additional DMRS for uplink in higher layer signaling; In case that an additional DMRS for uplink is configured by higher layer signaling, receiving the additional DMRS at the twelfth symbol of the time slot of the duration of 14 symbols; as well as In case three additional DMRSs for uplink are configured by higher layer signaling, the additional DMRSs are received at the sixth symbol, the ninth symbol, and the twelfth symbol of a time slot having a duration of 14 symbols.

6. A method performed by a terminal in a wireless communication system, the method comprising: Receiving a master information block MIB on a physical broadcast channel PBCH, the MIB comprising information on a position of a first demodulation reference signal DMRS for a first time slot type; identifying a time slot type from a first time slot type and a second time slot type; In a case where the time slot type is the first time slot type, receiving a first DMRS on one of a third symbol or a fourth symbol of the time slot in the downlink based on the MIB; as well as In case the time slot type is the second time slot type, a first DMRS is received on a first symbol of the scheduled downlink data resource.

7. The method according to claim 6, further comprising: Determining that a first DMRS is located on a first symbol of a scheduled downlink data resource; as well as In case the identified slot type is the second slot type and the physical downlink shared channel PDSCH allocation conflicts with resources reserved for the control region resources CORESET, a first DMRS is received on a first symbol after the CORESET.

8. The method according to claim 6, further comprising: receiving information about additional DMRS for downlink in higher layer signaling; In the case where three additional DMRSs for downlink are configured by higher layer signaling, determining that the additional DMRSs are located at the sixth symbol, the ninth symbol, and the twelfth symbol of the time slot having a duration of 14 symbols; and Based on the information about the additional DMRS, the additional DMRS for the downlink is received at the determined position.

9. The method according to claim 6, further comprising: In case the slot type is the first slot type, a position of a first DMRS used in uplink is determined on one of a third symbol or a fourth symbol of the slot based on the MIB.

10. The method according to claim 9, further comprising: receiving information about additional DMRS for uplink in higher layer signaling; In case an additional DMRS for uplink is configured by higher layer signaling, the additional DMRS is sent on the twelfth symbol of the time slot of the duration of 14 symbols; as well as In case three additional DMRSs for uplink are configured by higher layer signaling, the additional DMRSs are transmitted on the sixth symbol, the ninth symbol and the twelfth symbol of a time slot having a duration of 14 symbols.

11. A base station in a wireless communication system, the base station comprising: Transceiver; as well as At least one processor configured to: Controlling the transceiver to send a master information block MIB on a physical broadcast channel PBCH, wherein the MIB includes information about a position of a first demodulation reference signal DMRS for a first time slot type; identifying a time slot type from a first time slot type and a second time slot type; In case the identified time slot type is the first time slot type, controlling the transceiver to transmit a first DMRS on one of a third symbol or a fourth symbol of the time slot in a downlink based on the MIB; as well as In case the identified time slot type is the second time slot type, the transceiver is controlled to transmit a first DMRS on a first symbol of the scheduled downlink data resource.

12. The base station according to claim 11, wherein: The at least one processor is further configured to control the transceiver to transmit a first DMRS on a first symbol after CORESET if the identified slot type is a second slot type and a physical downlink shared channel (PDSCH) allocation conflicts with resources reserved for control region resources CORESET.

13. The base station according to claim 11, wherein: The at least one processor is further configured to: Controlling the transceiver to send information about additional DMRS for downlink in higher layer signaling; In case that three additional DMRSs for downlink are configured by higher layer signaling, the transceiver is controlled to transmit the additional DMRSs at the sixth symbol, the ninth symbol and the twelfth symbol of the time slot having a duration of 14 symbols.

14. The base station according to claim 11, in, The at least one processor is further configured to: controlling the transceiver to receive a first DMRS from a terminal in an uplink, Wherein, in the case where the time slot type is the first time slot type, the position of the first DMRS used in the uplink is determined based on the MIB on one of the third symbol or the fourth symbol of the time slot.

15. The base station according to claim 14, wherein: The at least one processor is further configured to: Controlling the transceiver to send information about additional DMRS for uplink in higher layer signaling; In case that an additional DMRS for uplink is configured by higher layer signaling, controlling the transceiver to receive the additional DMRS at the twelfth symbol of the time slot of the duration of 14 symbols; as well as In case three additional DMRSs for uplink are configured by higher layer signaling, the transceiver is controlled to receive the additional DMRSs at the sixth symbol, the ninth symbol and the twelfth symbol of the time slot having a duration of 14 symbols.

16. A terminal in a wireless communication system, the terminal comprising: Transceiver; as well as At least one processor configured to: Controlling the transceiver to receive a master information block MIB on a physical broadcast channel PBCH, wherein the MIB includes information about a position of a first demodulation reference signal DMRS for a first time slot type; identifying a time slot type from a first time slot type and a second time slot type; In case the time slot type is the first time slot type, controlling the transceiver to receive a first DMRS on one of a third symbol or a fourth symbol of the time slot in a downlink based on the MIB; as well as In case the time slot type is the second time slot type, the transceiver is controlled to receive a first DMRS on a first symbol of the scheduled downlink data resource.

17. The terminal according to claim 16, wherein: The at least one processor is further configured to: In case the identified slot type is the second slot type and a physical downlink shared channel (PDSCH) allocation conflicts with resources reserved for control region resources CORESET, the transceiver is controlled to receive a first DMRS on a first symbol after CORESET.

18. The terminal according to claim 16, wherein: The at least one processor is further configured to: controlling the transceiver to receive information about additional DMRS for downlink in higher layer signaling, and In the case where three additional DMRSs for downlink are configured by higher layer signaling, it is determined that the additional DMRSs are located at the sixth symbol, the ninth symbol, and the twelfth symbol of the time slot having a duration of 14 symbols, and The transceiver is controlled to receive the additional DMRS for a downlink at a determined position based on the information about the additional DMRS.

19. The terminal according to claim 16, wherein: The at least one processor is further configured to: In case the slot type is the first slot type, a position of a first DMRS used in uplink is determined on one of a third symbol or a fourth symbol of the slot based on the MIB.

20. The terminal according to claim 19, wherein: The at least one processor is further configured to: controlling the transceiver to receive information about additional DMRS for uplink in higher layer signaling; In case that an additional DMRS for uplink is configured by higher layer signaling, controlling the transceiver to send the additional DMRS at the twelfth symbol of the time slot of the duration of 14 symbols; as well as In case three additional DMRSs for uplink are configured by higher layer signaling, the transceiver is controlled to transmit the additional DMRSs at the sixth symbol, the ninth symbol and the twelfth symbol of the time slot having a duration of 14 symbols.

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