KR20200115152A - Method for transmitting and receiving a discovery reference signal, and apparatus for the same - Google Patents

Abstract

The present invention is to provide a method of transmitting and receiving a discovery reference signal (DRS) in a mobile communication system operating in an unlicensed band. According to the present invention, an operation method of a terminal receiving a DRS may comprise the steps of: receiving a first DRS from a base station; determining the number of DRSs configured in one slot based on indication information included in a physical broadcast channel (PBCH) of a synchronization signal (SS)/PBCH block included in the first DRS; when it is determined that one DRS is configured in one slot, determining a resource configuration method of a physical downlink shared channel (PDSCH) for reception of remaining system information (RMSI) included in the first DRS as type A, and when it is determined that two or more DRSs are configured in one slot, determining a resource configuration method of the PDSCH as type B; and receiving the PDSCH according to the determined resource configuration method.

Description

A method for transmitting and receiving a discovery reference signal, and an apparatus for the same

The present invention relates to a method and apparatus for transmitting and receiving a discovery reference signal (DRS), and more particularly, to a method and apparatus for transmitting a DRS for a communication system operating in an unlicensed band.

In the NR-U system operating in an unlicensed spectrum to increase network capacity by increasing the utilization of limited frequency resources, the discovery reference signal (DRS, Discovery) transmitted from the base station (eg, gNB) by terminals is similar to the general NR system. Reference Signal) can be used to determine whether the base station transmits a signal. For DRS transmission, the NR-U system must comply with the regulations on the transmission band, transmission power, and transmission time according to the use of the unlicensed band. In particular, when a signal is transmitted in an unlicensed band, the transmission signal must be configured and transmitted to occupy 80% of the total channel bandwidth (eg, 20 MHz) according to OCB (Occupied Channel Bandwidth) regulations. In addition, in the case of the NR-U system, a Listen Before Talk (LBT) procedure must be performed for coexistence with other systems according to the characteristics of the unlicensed band before transmitting the DRS.

Therefore, in the NR-U system, DRS transmission is difficult to predict the actual transmission time, unlike transmission of a synchronization signal/physical broadcast channel (SS/PBCH) block of a general NR system.In order to comply with OCB regulations, system information or There is a problem that the reference signal must be multiplexed with the SS/PBCH block and transmitted.

An object of the present invention for solving the above problems is to provide a method of transmitting and receiving a discovery reference signal (DRS) in a mobile communication system operating in an unlicensed band.

Another object of the present invention for solving the above problems is to provide an apparatus for transmitting and receiving DRS in a mobile communication system operating in an unlicensed band.

An embodiment of the present invention for achieving the above object is a method of operating a terminal for receiving a discovery recovery signal (DRS), comprising: receiving a first DRS from a base station; Determining the number of DRSs configured in one slot based on indication information included in the PBCH of a synchronization signal/physical broadcast channel (SS/PBCH) block included in the first DRS; When it is determined that one DRS is configured in one slot, a resource configuration method of a physical downlink shared channel (PDSCH) for reception of RMSI (remaining system information) included in the first DRS is determined as type A, and one Determining a resource configuration method of the PDSCH as type B when it is determined that two or more DRSs are configured in the slot; And receiving the PDSCH according to the determined resource setting method.

According to the present invention, when channel estimation is performed by simultaneously utilizing two types of DM-RS mapped to one symbol, an improved channel estimation effect can be obtained, and a performance improvement effect can be obtained accordingly.

1 is a conceptual diagram illustrating a type 1 frame structure of an LTE system.
2 is a conceptual diagram illustrating a type 2 frame structure of an LTE system.
3 is a conceptual diagram for describing transmission of an SS burst set in an NR system.
4 is a conceptual diagram illustrating a configuration of a synchronization signal block in an NR system.
5 is a conceptual diagram illustrating an example of dividing a broadband component carrier (CC) into a plurality of bandwidth parts (BWP) in an NR system and transmitting an SSB in each BWP.
6 is a conceptual diagram illustrating three basic patterns for setting RMSI CORESET in an NR system.
7 is a conceptual diagram illustrating a case in which two DRSs in which an SS/PBCH block and RMSI are multiplexed are configured in one slot.
FIG. 8 is a conceptual diagram illustrating a case in which a DRS is composed of 6 symbols and an RMSI PDCCH transmission region is set to two OFDM symbols.
9 is a conceptual diagram illustrating a case in which only one DRS in which an SS/PBCH block and an RMSI are multiplexed is configured in one slot.
10 is a conceptual diagram illustrating a configuration in which an SS/PBCH block and an RMSI PDCCH/PDSCH are multiplexed in a DRS.
FIG. 11 is a conceptual diagram illustrating methods for configuring a front-loaded DM-RS of an RMSI PDSCH when an RMSI PDCCH transmission region is configured as in FIG. 10.
12 is a conceptual diagram illustrating a case where an RMSI PDCCH DM-RS is shared with an RMSI PDSCH without a separate RMSI PDSCH DM-RS.
13 is a conceptual diagram illustrating a case of mapping the RMSI PDSCH DM-RS to the same symbol position as the PBCH DM-RS.
14 is a conceptual diagram illustrating a case in which an RMSI PDSCH DM-RS is transmitted after an SS/PBCH block transmission region.
15 is a conceptual diagram for comparing RMSI PDSCH data mapping of an NR system and RMSI PDSCH data mapping of an NR-U system.
16 is a block diagram illustrating a communication node according to embodiments of the present invention.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals have been used for similar elements.

Terms such as first, second, A, and B may be used to describe various elements, but the elements should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The 3GPP Long Term Evolution (LTE) system, one of the conventional mobile communication technologies, supports three types of frame structures. The first is a Type 1 frame structure applicable to FDD (Frequency Division Duplex), the second is a Type 2 frame structure applicable to TDD (Time Division Duplex), and the last is a Type 3 frame structure for transmission of an unlicensed frequency band. to be.

1 is a conceptual diagram illustrating a type 1 frame structure of an LTE system.

Referring to FIG. 1, one radio frame has a length of 10 ms (307200Ts) and is composed of 10 subframes. Here, Ts is a sampling time and has a value of Ts=1/(15kHz*2048). Each subframe has a length of 1 ms, and one subframe consists of two slots of 0.5 ms. One slot consists of 7 OFDM symbols in case of a normal CP and 6 OFDM symbols in case of an extended CP.

2 is a conceptual diagram illustrating a type 2 frame structure of an LTE system.

Referring to FIG. 2, the relationship between the radio frame, the subframe, and the slot and the lengths of each are the same as in the case of Type 1. As a difference, one radio frame is composed of a downlink subframe, an uplink subframe, and a special subframe. The special subframe exists between the downlink subframe and the uplink subframe, and includes a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), and an Uplink Pilot Time Slot (UpPTS). One radio frame includes two special subframes when the downlink-uplink switching period is 5ms, and includes one special subframe when the downlink-uplink switching period is 10ms. DwPTS is used for cell search, synchronization, or channel estimation, and GP is a section for removing interference occurring in the uplink of a base station due to a multipath delay difference of terminals, and a PRACH (Physical Random Access Channel) or SRS (Sounding) in the UpPTS section. Reference Signal) can be transmitted.

In the LTE system, a Transmission Time Interval (TTI) refers to a basic time unit in which an encoded data packet is transmitted through a physical layer signal. LTE Release 14 defines short TTI-based data transmission to meet the low-latency requirements. In order to distinguish the TTI prior to Release 14 from the short TTI, it is referred to as a base TTI or a regular TTI.

The basic TTI of the LTE system consists of one subframe. That is, the length of the time axis of a physical resource block (PRB) pair, which is the smallest unit of resource allocation, is 1 ms. In order to support transmission in units of 1ms TTI, most physical signals and channels are also defined in units of subframes. For example, a cell-specific reference signal (CRS), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical uplink control channel ( A physical uplink control channel (PUCCH), and a physical uplink shared channel (PUSCH) exist for each subframe. On the other hand, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) exist every 5th subframe, and a physical broadcast channel (PBCH) is every 10th subframe. Each exists. Meanwhile, a radio frame consists of 10 subframes and has a time axis length of 10ms. Radio frames are distinguished by a system frame number (SFN), and SFN is used to define transmission of signals with a transmission period longer than one radio frame (e.g., paging, channel estimation reference signal, and channel status information reporting), The cycle of SFN is 1024.

In the LTE system, the PBCH is a physical layer broadcasting channel that transmits the most essential system information called MIB (Master Information Block), and is transmitted every 10th subframe, and is transmitted once in one radio frame. The MIB information must be transmitted during four radio frames, and after that, it may be changed according to the situation of the system. For convenience, this is referred to as PBCH TTI (=40ms). At this time, the information of the transmitted MIB is 3 bits representing the system band, 3 bits of information related to the physical hybrid ARQ indicator channel (PHICH), 8 bits of SFN, 10 bits reserved for future use, 16 bits of cyclic redundancy check (CRC), a total of 40 It consists of bits. SFN information for classifying radio frames is composed of a total of 10 bits (B9 to B0), of which only 8 bits (B9 to B2) of the MSB (Most Significant Bit) are transmitted through the PBCH. Corresponding SFN information transmitted through is not changed. In addition, the LSB (Least Significant Bit) 2 bits (B1~B0) of SFN that change during four radio frames are not explicitly given by the MIB transmitted on the PBCH, but implied through a scrambling sequence used for the PBCH. Transmitted as an enemy. As the PBCH scrambling sequence, a gold sequence that is generated by initializing a cell identifier (cell ID) is used, and is newly initialized with four radio frame periods by the formula of mod(SFN,4). Therefore, for each radio frame in which the SFN LSB 2-bit information is '00', the newly generated gold sequence is initialized with the cell ID and is applied as the scrambling sequence. It is used for PBCH scrambling in radio frames ending with '10' and '11'. Therefore, the UE that acquired the cell ID in the initial cell search process can implicitly find out information on '00', '01', '10', and '11' of SFN LSB 2 bits through the scrambling sequence in the PBCH decoding process. have. Finally, 10 bits of SFN information (B9 to B0) can be found by combining 2 bits (B1 to B0) found through the scrambling sequence and 8 bits (B9 to B2) explicitly transmitted through the PBCH.

The mobile communication network, which has evolved after LTE, has to satisfy technical requirements for supporting a wider variety of service scenarios as well as high transmission rates, which have been the main concern in the related art. Recently, ITU-R has defined key performance indicators (KPIs) and requirements for IMT-2020, the official name of 5G mobile communication, which is a high transmission rate (eMBB; enhanced mobile broadBand) and a short transmission delay. It is summarized as time (URLLC; ultra reliable low latency communication) and massive terminal connectivity (mMTC; massive machine type communication). According to the ITU-R projected schedule, it aims to allocate frequencies for IMT-2020 in 2019 and complete international standard approval by 2020.

3GPP is developing a 5G standard specification based on a new radio access technology (RAT) that satisfies the IMT-2020 requirements. According to the definition of 3GPP, the new radio access technology is a radio access technology that does not have backward compatibility with the existing 3GPP radio access technology, and a new radio communication system after LTE adopting such radio access technology is described herein. It is referred to as NR (new radio).

One of the characteristics that NR differs from conventional 3GPP systems such as CDMA and LTE is that it utilizes a wide range of frequency bands to increase transmission capacity. In this regard, the WRC-15 administered by the ITU has set the next WRC-19 agenda to review the 24.25~86GHz band as a candidate frequency band for IMT-2020. 3GPP considers a band below 1GHz to a band of 100GHz as NR candidate bands.

As a waveform technology for NR, candidates such as orthogonal frequency division multiplexing (OFDM), filtered OFDM, generalized frequency division multiplexing (GFDM), filter bank multi-carrier (FBMC), universal filtered multi-carrier (UFMC), etc. It is being discussed as a technology. Each has its advantages and disadvantages, but cyclic prefix (CP)-based OFDM and SC-FDMA (single carrier-frequency division multiple access) are due to the relatively low implementation complexity and multiple-input multiple-output (MIMO) scalability, It is still an effective method for 5G systems. However, in order to flexibly support various 5G usage scenarios, it is possible to consider a method of simultaneously accommodating different Waveform parameters in one carrier without a guard band.For this, out-of-band emission Filtered OFDM or GFDM having a small frequency spectrum (OOB; out of band emission) may be suitable.

In the present invention, for convenience of explanation, it is assumed that CP-based OFDM (CP-OFDM) is a waveform technology for wireless access. However, this is only for convenience of explanation, and the scope of the claim of the present invention is not limited to a specific waveform technology. In general, the category of CP-based OFDM technology includes Filtered OFDM or spread spectrum OFDM (eg, DFT-spread OFDM) technology.

One of the biggest factors determining the subcarrier spacing of an OFDM system is a carrier frequency offset (CFO) experienced at the receiving end, which is affected by the Doppler effect and phase drift. It has a characteristic that increases proportionally. Therefore, in order to prevent performance degradation due to a carrier frequency offset, the subcarrier spacing should increase in proportion to the operating frequency. On the other hand, if the subcarrier spacing is too large, there is a disadvantage that CP overhead increases. Therefore, the subcarrier spacing should be defined as an appropriate value considering channel and RF characteristics for each frequency band.

In the NR system, various numerology is being considered. For example, 15 kHz, which is a subcarrier spacing of the existing LTE, and a subcarrier spacing of 30 kHz, 60 kHz, and 120 kHz scaled by 2 times, 4 times and 8 times, may be considered together. Configuring the subcarrier spacings of heterogeneous neurons to differ by an exponential power of 2 may be advantageous for carrier aggregation based on heterogeneous neurons, multiplexing heterogeneous neurons within one carrier, and frame structure design.

NR systems are expected to be used in a wide range of frequency bands from hundreds of MHz to tens of GHz. In general, since the diffraction and reflection characteristics of radio waves are not good at high frequencies, the propagation characteristics are generally poor, and propagation losses such as path-loss and reflection loss are low at low frequencies. Since it is known to be relatively large compared to the (low frequency) region, when the NR system is deployed in the high frequency region, cell coverage may be reduced compared to the existing low frequency region. In order to solve this problem, a method of increasing cell coverage through beamforming using a plurality of antenna elements at high frequencies may be considered.

Beamforming methods include digital beamforming and analog beamforming. In digital beamforming, a beamforming gain is obtained using a plurality of radio frequency (RF) paths based on a multiple input multiple output (MIMO) and a digital precoder or a codebook, Analog beamforming is performed through a number of analog/RF devices such as a phase shifter, a power amplifier (PA), and a variable gain amplifier (VGA) and an antenna array. Get foaming benefits. Digital beamforming increases beamforming gain because expensive digital-to-analog converter (DAC) or analog-to-digital converter (ADC) is required, and the same number of TXRUs (transceiver units) as antenna elements are required. In order to achieve this, the complexity of the antenna implementation increases proportionally. In analog beamforming, since a plurality of antenna elements are connected to one TXRU through phase shifters, even if the antenna elements are increased to increase the beamforming gain, the corresponding implementation complexity is not significantly increased. However, since the beamforming performance is inferior to that of the digital method and the phase shifter is adjusted in time, the efficient use of frequency resources is limited. Therefore, a hybrid beamforming method that is a combination of the analog method and the digital method may be used.

When cell coverage is increased through beamforming, not only the control channel and data transmitted to each terminal in the cell, but also the common control channel and signals transmitted to all terminals in the cell, should be transmitted after applying beamforming. do. When beamforming is applied to increase cell coverage and transmits a common control channel and signal to all terminals, it is not possible to transmit a common control channel and signal to the entire cell area at once, and multiple beams are transmitted several times for a certain period of time. Should be transmitted through. Transmitting multiple beams while changing multiple beams is called beam sweeping. In the case of transmitting a common control channel and signal using beamforming, such a beam sweeping operation is necessary.

A terminal accessing the system acquires downlink frequency/time synchronization and cell ID information through a synchronization signal (SS), and obtains uplink synchronization and uplink synchronization through a random access procedure. Form a link. In this case, the NR system supports multiplexing of NR-SS and NR-PBCH that are periodically transmitted in the TDM scheme, and transmits them in N (=4) OFDM symbols. These N OFDM symbols are defined as an SS block (SSB). When transmitting an SSB using beamforming, a beam sweeping operation in which multiple beams are transmitted while changing multiple times is required.To this end, multiple SSBs can be defined within the transmission period of NR-SS and NR-PBCH. A number of SSBs are gathered to form an SS burst set.

3 is a conceptual diagram for describing transmission of an SS burst set in an NR system.

Referring to FIG. 3, the SS burst set is periodically repeated, and at a period of the SS burst set, the base station transmits SSBs to terminals in a cell through different beams in a beam sweeping manner. The maximum number L of SSBs constituting one SS burst set and the positions of L SSBs are defined in the standard, and L may have different values according to the system frequency domain. Among the L SSBs, the number and location of SSBs used for actual transmission may be determined by the network.

4 is a conceptual diagram illustrating a configuration of a synchronization signal block in an NR system.

Referring to FIG. 4, one SSB is time domain multiplexing (TDM) in the order of PSS, PBCH, SSS, and PBCH, and PBCHs may be transmitted in both frequency bands of the SSS. In addition, the SSB index can be found through PBCH DMRS when the maximum number of SSBs L=8 in the sub6GHz frequency band, and 6 indicating the SSB index when the maximum number of SSBs L=64 in the over6GHz frequency band. Of the bits, 3 LSB bits are found through PBCH DMRS, and 3 remaining MSB bits are transmitted through PBCH payload, so it can be found by performing decoding on the PBCH.

The NR system can support a system bandwidth of up to 400MHz, but in the case of a terminal, the size of the bandwidth that can be supported may vary according to the capabilities of the terminal. Therefore, some terminals accessing the broadband system can be accessed through only part of the entire system bandwidth. In order to facilitate the access of terminals supporting various bandwidth sizes in a system supporting such a broadband, a synchronization signal and PBCH are always transmitted to the center of the system bandwidth. Unlike the existing LTE, SSBs can be transmitted to multiple locations along the frequency axis in the NR system have.

5 is a conceptual diagram illustrating an example of dividing a broadband component carrier (CC) into a plurality of bandwidth parts (BWP) in an NR system and transmitting an SSB in each BWP.

Referring to FIG. 5, the terminal may perform initial access using one of SSBs transmitted through each BWP. After SSB is detected, the UE performs a cell access operation by acquiring remaining minimum system information (RMSI), and the RMSI is transmitted to the PDSCH through PDCCH scheduling. At this time, configuration information of CORESET (COntrol REsource SET) through which the PDCCH containing scheduling information of the RMSI PDSCH is transmitted is transmitted through the PBCH in the SSB. When multiple SSBs are transmitted in the entire system band, some SSBs may transmit an RMSI associated with the corresponding SSB, and some SSBs may not have an RMSI associated with the corresponding SSB. At this time, the SSB with the associated RMSI is defined as'cell defining SSB', and the cell search and initial access process of the terminal can be performed only through the'cell defining SSB'. SSBs without an associated RMSI can be used for synchronous work performance or measurement purposes in the corresponding BWP. In this case, the BWP through which the SSB is transmitted may be limited to some of various BWPs in the broadband.

As described above, RMSI reception is performed through a series of processes of detecting PDCCH through CORESET configuration information transmitted through PBCH, obtaining scheduling information of RMSI through this, and receiving PDSCH accordingly. At this time, the control channel resource region in which the PDCCH can be transmitted is set through the RMSI CORESET setting information, which can have three patterns largely as follows.

6 is a conceptual diagram illustrating three basic patterns for setting RMSI CORESET in an NR system.

In order to set the RMSI CORESET, one of the three patterns illustrated in FIG. 6 is selected, and detailed settings are completed within the selected pattern. In Patten 1, SSB, RMSI CORESET, and RMSI PDSCH are all TDM. In Pattern 2, RMSI CORESET and RMSI PDSCH are TDM, and only RMSI PDSCH is SSB and frequency domain multiplexing (FDM). In Pattern 3, RMSI CORESET and RMSI PDSCH are TDM, and both RMSI CORESET and RMSI PDSCH are SSB and FDM. In the frequency band below 6GHz, only Pattern 1 is used, and in the frequency band above 6GHz, Patterns 1, 2, and 3 can all be used. In addition, the newmanology used for SSB, RMSI CORESET and RMSI PDSCH may be different. In the case of Pattern 1, all combinations of the newmanology can be used, and in the case of Pattern 2, {SSB, RMSI} = {120kHz, 60kHz}, Only the combination of {240kHz, 120kHz} can be used, and in the case of Pattern 3, only the combination of {SSB, RMSI} = {120kHz, 120kHz} can be used.

RMSI CORESET setting information selects one of the above three patterns according to the combination of SSB and RMSI's new manology, and the number of RBs (Resource Blocks) of RMSI CORESET, number of symbols of CORESET, RB of SSB and RB of RMSI CORESET Table A showing offset information and Table B showing information for setting monitoring occasions of RMSI PDCCH such as the number of search space sets per slot in each pattern, CORESET offset, and OFDM symbol index. Consists of. Each of Tables A and B is composed of several actual tables (Table A: Table 13-1 to Table 13-8, Table B: Table 13-9 to Table 13-13), and Tables A and B are each 4 bits. It is configured and displayed as 8-bit information.

In the NR system, the PDSCH is mapped and transmitted in one of two types of mapping methods on the time axis. The two mapping types are Type A and Type B, and are organized as shown in Table 1 below.

PDSCH mapping type General CP Extended CP S L S+L S L S+L Type A {0,1,2,3}
(Reference 1) {3,...,14} {3,...,14} {0,1,2,3}

(Reference 1) {3,...,12} {3,...,12} Type B {0,...,12} {2,4,7} {2,...,14} {0,...,10} {2,4,6} {2,...,12} Note 1: S=3 is applicable only when dmrs-TypeA-Position is 3

Type A is a slot-based transmission, and the starting position of the PDSCH symbol can be set to one of {0, 1, 2, 3}, and the number of PDSCH transmission symbols is a slot boundary in case of a normal CP. It can be set to one value from 3 to 14 within the range not exceeding ). The Type B scheme is non-slot-based transmission, and the starting position of the PDSCH symbol can be set to one of 0 to 12, and the number of PDSCH transmission symbols is within a range that does not cross the slot boundary in case of a normal CP. It can be set to one of {2, 4, 7}.

As NR phase 1 standardization is completed in 3GPP release 15 and phase 2 standardization is in progress in release 16, new features for the NR system are being discussed. One of the representative ones is NR-U (Unlicensed). NR-U is a technology for supporting operation in an unlicensed spectrum used in a communication system such as Wi-Fi in order to increase network capacity by increasing the utilization of limited frequency resources. The 3GPP communication system for operation in the unlicensed band began standardization with the LTE-LAA (Licensed-Assisted Access) technology in 3GPP release 13, release 14 LTE-eLAA (Enhanced LAA) and release 15 LTE-FeLAA (Further Enhanced LAA). ) Through continuous development. In NR, after SI (study item) for NR-U, standardization work is in progress through WI (work item) in release 16.

In NR-U, as in a general NR system, UEs can determine whether or not to transmit a signal from a base station through a discovery reference signal (DRS) transmitted from a base station (eg, gNB). In particular, in the NR-U in the SA (Stand-Alone) mode, the UE may acquire synchronization and system information through DRS. In the NR-U system, the DRS transmission must comply with the rules for the use of the unlicensed band (eg, the rules for the transmission band and transmission power, and the transmission time). In particular, when a signal is transmitted in an unlicensed band, the transmission signal must be configured and transmitted to occupy 80% of the total channel bandwidth (eg, 20 MHz) according to OCB (Occupied Channel Bandwidth) regulations.

In addition, in the case of NR-U, before transmitting signals and data as well as DRS, a Listen Before Talk (LBT) procedure must be performed for coexistence with other systems due to the characteristics of the unlicensed band. The LBT procedure is a procedure for checking whether other base stations, other terminals, and other systems are transmitting signals before transmitting signals. The base station or the terminal of the NR-U system may determine whether to transmit another signal for a certain period through the LBT procedure, and transmit its own signal when it is determined that there is no signal to be transmitted. If the LBT procedure fails, the base station or the terminal cannot transmit a signal. Depending on the type of transmitted signal, various categories of LBT may be performed before transmission of the corresponding signal.

RMSI PDSCH DM-RS transmission method in DRS

In the case of the DRS of NR-U, a synchronization signal/physical broadcast channel (SS/PBCH) block of NR may be basically included for synchronization acquisition and channel measurement. In NR-U, the transmission of DRS must also satisfy OCB regulations. The SS/PBCH block of the existing NR is composed of a maximum of 20 resource blocks (RB), so when the subcarrier spacing is 15KHz, it occupies only 3.6MHz band and when the subcarrier spacing is 30kHz, it occupies only 7.2MHz band. Therefore, in order to transmit the DRS by satisfying the OCB regulation in the NR-U, signals/channels other than the SS/PBCH block may be multiplexed and transmitted together with the DRS.

To this end, in the case of NR-U in a standalone (SA) mode, RMSI, which is essential system information, may be multiplexed like an SS/PBCH block to transmit a DRS. On the other hand, in the case of NR-U in NSA (Non-Stand Alone) mode, system information is transmitted from PCell (Primary Cell) of the existing licensed band, so CSI-RS (Channel State Information-) for channel measurement instead of system information Reference Signal) or a Tracking-Reference Signal (T-RS), etc. may be multiplexed with an SS/PBCH block to transmit DRS. Alternatively, multiple SS/PBCH blocks may be transmitted on the frequency axis to satisfy OCB regulations. Meanwhile, in the SA mode, CSI-RS and T-RS can be transmitted with the SS/PBCH block instead of system information, and system information instead of the CSI-RS and T-RS can be transmitted together with the SS/PBCH block in the NSA mode.

7 is a conceptual diagram illustrating a case in which two DRSs in which an SS/PBCH block and RMSI are multiplexed are configured in one slot.

Referring to slots (a) and (b) of FIG. 7, the positions of the SS/PBCH block #n+1 are different, but the DRS consists of 7 OFDM symbols in each slot. At this time, if the RMSI PDCCH transmission region is set to one OFDM symbol, regardless of slots (a) and (b) of FIG. 7, the RMSI PDCCH transmission region is OFDM symbol #0 for DRS #n and OFDM symbol #0 for DRS #n+1. It will be set in symbol #7. If the RMSI PDCCH transmission region is set to two OFDM symbols, in the case of FIG. 7(b), the RMSI PDCCH transmission region is set in OFDM symbols #0 and #1 in DRS #n, and the RMSI PDCCH transmission region in DRS #n+1. This will be set in OFDM symbols #7 and #8. However, in the case of slot (a) of FIG. 7, it is impossible to configure the RMSI PDCCH transmission region with two OFDM symbols. If it is desired to set the RMSI PDCCH transmission region to two OFDM symbols in slot (a) of FIG. 7, the DRS may consist of six OFDM symbols.

FIG. 8 is a conceptual diagram illustrating a case in which a DRS is composed of 6 symbols and an RMSI PDCCH transmission region is set to two OFDM symbols.

Referring to FIG. 8, when the SS/PBCH block pattern as shown in the slot (a) of FIG. 7 is applied, a case in which a DRS is composed of 6 OFDM symbols and an RMSI PDCCH transmission region is set to two OFDM symbols is an example. Has been. At this time, in DRS #n, the RMSI PDCCH transmission region will be set in symbols #0 and #1, and in DRS #n+1, the RMSI PDCCH transmission region will be set in symbol #6 and symbol #7.

In the NR-U system, the transmission of the DRS is also determined according to the success of the LBT operation, so when the LBT operation is successful, it is necessary to transmit as much information as possible in a short time. In the case of the RMSI PDSCH transmission region in the DRS, it is set in a region other than the RMSI PDCCH transmission region in the DRS resource region, and it is necessary to increase the resource efficiency as much as possible. At this time, there occurs a case where the configuration of the RMSI PDSCH resource region in the DRS is not supported by the PDSCH configuration method of the existing NR.

For example, in the case of DRS #n, the RMSI PDSCH can be configured according to the Type A mapping method regardless of the RMSI PDCCH transmission region configuration. However, in the case of FIG. 7, when the RMSI PDSCH is set in the Type A mapping method in DRS #n+1, the position of the PDSCH start symbol is also set to {8, 9} in addition to the existing {0, 1, 2, 3} You need to make it possible. In the case of FIG. 7, two DRSs in one slot are each composed of seven symbols. However, as in the case of FIG. 8, when the number of symbols constituting the DRS is set differently (for example, six symbols ) May also require addition of the position of the PDSCH start symbol of {7}. On the other hand, in the case of configuring the RMSI PDSCH according to the Type B mapping method, the number of PDSCH transmission symbols is limited to {2, 4, 7}, and thus the RMSI PDCCH resource region is limited to 1 or 2 OFDM symbols in the DRS configuration in FIG. If so, it is necessary to add the number of {5, 6} PDSCH transmission symbols.

When there is a lot of RMSI system information, it may be difficult to configure two DRSs in one slot as in the case of FIG. 7 or 8. Also, for other reasons, it may be necessary to configure and transmit only one DRS in one slot.

9 is a conceptual diagram illustrating a case in which only one DRS in which an SS/PBCH block and an RMSI are multiplexed is configured in one slot.

Referring to FIG. 9, unlike the cases of FIGS. 7 and 8, only the first SS/PBCH block of two SS/PBCH blocks in a slot is configured. However, it is also possible to configure the second SS/PBCH block in slot (a) or (b) of FIG. 7.

In this way, when only one SS/PBCH block is set in the slot and only one DRS is set, the number of OFDM symbols constituting the DRS can be set below the number of symbols in the slot according to the RMSI PDCCH resource region and the RMSI PDSCH resource region. As shown in FIG. 9, when only one DRS is configured in one slot, the PDSCH resource can be configured using the Type A mapping method of the existing Rel-15 NR regardless of the transmission location of the SS/PBCH block. In the existing Rel-15 NR, in the case of receiving RMSI PDSCH, Type A mapping method is basically applied. However, in the NR-U system, when two DRSs are configured in one slot as shown in FIGS. 7 and 8, a Type B mapping method in which the number of PDSCH transmission symbols is added may be advantageous, and in one slot as shown in FIG. When one DRS is set, a Type A mapping method may be advantageous.

Accordingly, the present invention proposes a method of applying a PDSCH resource mapping scheme differently according to the configuration of the DRS. That is, when a plurality of DRSs are configured in one slot, the Type B mapping method is applied to the RMSI PDSCH resource configuration, and when one DRS is configured in one slot, the Type A mapping method is applied to the RMSI PDSCH resource configuration. Can be applied. At this time, it should be noted that the division of the DRS into the plural or the singular refers to the number of DRSs set in one slot and is not related to the number of DRSs actually transmitted.

In this way, it may be necessary to inform the UE of the configuration information of the DRS in the slot not only to determine the resource mapping method but also to reduce the complexity of the UE. In the case of the NR-U system operating in the NSA mode, such configuration information can be transmitted through the PCell, but in the case of the NR-U system operating in the SA mode, the initial access terminal cannot know the information.

Accordingly, the present invention proposes a method of transmitting the configuration information of the DRS to the terminal through the PBCH included in the SS/PBCH block. The UE that detects the SS/PBCH block in the DRS can obtain the PBCH information in the SS/PBCH block to find out the DRS configuration information, and accordingly, can check the RMSI PDSCH resource setting method, etc., thereby reducing the complexity of obtaining initial system information. have. In this case, the configuration information of the DRS transmitted through the PBCH may be 1-bit information indicating whether only one DRS is configured or a plurality of DRSs are configured in the slot. Alternatively, the DRS configuration information transmitted through the PBCH may be more detailed DRS configuration information including RMSI PDCCH resource configuration. For example, configuration information of the DRS can be found through a case in which a plurality of RMSI PDCCH resource configurations in a DRS is supported and a case where a single number is supported.

When the SS/PBCH block and RMSI for transmitting system information are multiplexed and transmitted in the DRS together, PDSCH DM-RS transmission is required for correct reception of the RMSI PDSCH. In the present invention, when the SS/PBCH block and RMSI are multiplexed and transmitted in the DRS, transmission methods of the RMSI PDSCH DM-RS are also proposed.

10 is a conceptual diagram illustrating a configuration in which an SS/PBCH block and an RMSI PDCCH/PDSCH are multiplexed in a DRS.

Referring to FIG. 10, an SS/PBCH block is transmitted in some frequency resources of four OFDM symbols corresponding to OFDM symbol #i to OFDM symbol #i+3, and RMSI PDCCH and RMSI PDSCH are transmitted in other time and frequency domains. Can be. In this case, for smooth reception of the RMSI PDSCH, the DM-RS for the RMSI PDSCH must be transmitted.

Meanwhile, in the NR system, a front-loaded DM-RS may be applied to minimize a data reception processing delay time. The front-loaded DM-RS is a DM-RS transmitted in an OFDM symbol at the front of the PDSCH through which data is transmitted. After the UE first receives the corresponding DM-RS, it performs channel estimation and sequentially It is a DM-RS introduced for the purpose of processing data received by the user.

In the current NR system, in the case of a front-loaded DM-RS, assuming that the symbol index in the slot starts from #0, it may be transmitted in OFDM symbol #2 or #3. Which of the OFDM symbols #2 and #3 the front-loaded DM-RS is transmitted is signaled through 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH. In the case of FIG. 8 as an example, OFDM symbol #i-2 corresponds to symbol 0 because it is the start symbol of a slot. At this time, since the front-loaded DM-RS is transmitted in OFDM symbol #i or #i+1, it is always overlapped with the transmission region of the SS/PBCH block regardless of the RMSI PDCCH transmission region setting value. Therefore, in the present invention, in the DRS transmission of NR-U, a method of setting the position of the front-loaded DM-RS to OFDM symbol #1 or #2 rather than OFDM symbol #2 or #3 of the existing NR system can be applied. have. This method can be supported by redefining the existing 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH in the NR-U system.

In addition, when two DRSs exist in one slot as shown in FIG. 7, if DRS #n+1 is set in the Type A mapping method, support is impossible even with the redefined front-loaded DM-RS configuration. Accordingly, the present invention proposes a method of configuring a front-loaded DM-RS when two DRSs exist in one slot and RMSI PDSCH resources are allocated according to the Type A mapping scheme. Therefore, when DRS #n+1 is set to the Type A mapping method, the front-loaded DM-RS must be set to one of {8, 9}, and this can be supported in one of the following methods.

(1) Setting through reinterpretation of front-loaded DM-RS indication information according to DRS location in slot

As an embodiment, when two DRSs are configured in one slot, the front-loaded DM-RS 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH indicates {1, 2} for the first DRS in the slot. For the second DRS, the front-loaded DM-RS 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH may be defined to indicate {8, 9}. At this time, the position of the first or second DRS in the slot may be replaced with a DRS index or an SSB index in the DRS and applied.

(2) SS/PBCH block or DRS index and front-loaded DM-RS indication information combined

As another embodiment, when two DRSs are configured in one slot, the actual front-loaded DM is a combination of the DRS index or the SSB index in the DRS and the front-loaded DM-RS 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH. -The symbol position of the RS can be determined. For example, when the DRS (or SS/PBCH block) index is an even number, the front-loaded DM-RS 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH is determined as the actual front-loaded DM-RS symbol position. And, if the DRS (or SS/PBCH block) index is odd, the length of the DRS (or RMSI PDSCH) in front-loaded DM-RS 1-bit indication information ( dmrs-TypeA-Position ) of the PBCH (duration, example of FIG. 7) In '7'), the symbol position of the actual front-loaded DM-RS can be determined.

That is, the method may be expressed by the following pseudo code.

If DRS (or SS/PBCH block) index = even, actual position of front-loaded DM-RS = dmrs-TypeA-Position

Else if DRS (or SS/PBCH block) index = odd, actual position of front-loaded DM-RS = dmrs-TypeA-Position + Ld, where Ld is the duration of DRS (or RMSI PDSCH)

Alternatively, the actual position of the front-loaded DM-RS may be set by a combination (eg, multiplication) of a modular operation of a DRS (or SS/PBCH block) index and a length of a DRS (or RMSI PDSCH). This can be expressed by the following equation.

Actual position of front-loaded DM-RS = dmrs-TypeA-Position + (DRS index(or SS/PBCH block index) mod 2)*Ld, where Ld is the duration of DRS (or RMSI PDSCH)

(3) Setting of various location information by expanding the PBCH DM-RS field for setting the location of the front-loaded DM-RS

As another embodiment, by extending 1-bit front-loaded DM-RS indication information ( dmrs-TypeA-Position ) in the current PBCH into a field composed of a plurality of bits, front-loaded in the first DRS and the second DRS. The location of the DM-RS can be set as an actual OFDM symbol index. In the case of FIG. 7 as an example, when the field is extended to 3 bits so that 1 to 9 can be set, when the RMSI PDCCH transmission region is set to one symbol, the first DRS is the 1st OFDM symbol, and the second DRS is 8 Each can be set as a th OFDM symbol. In such a method, the location of the front-loaded DM-RS can be directly set, but there may be indexes that are not actually used, and the PBCH content for each DRS is different (i.e., improvement of reception performance through PBCH combination) There is a difficult problem).

In the NR system, the ld value (different from Ld described above) that determines the number and location of front-loaded DM-RSs and additional DM-RSs is the number of symbols from the start of the slot to the last symbol of the PDSCH in the case of the Type A mapping method. In the case of the Type B mapping scheme, it is defined as the number of symbols from the PDSCH start symbol to the PDSCH last symbol. If the RMSI PDSCH resource of DRS #n+1 is set in the Type A mapping method, since ld is always calculated from the beginning of the slot, the ld value is calculated large even if the number of actual RMSI PDSCH transmission symbols is not large, so that an additional DM-RS is set. do. To solve this problem, we propose a new calculation method by defining the ld value as in Type B or subtracting the number of symbols constituting the DRS from the previously calculated ld value in the case of DRS #n+1. Alternatively, the above problem can be solved by applying a Type B mapping scheme in which the front-loaded DM-RS is always mapped to the start symbol of the PDSCH.

If this method is applied to the NR system as it is, in the case of (a) of FIG. 10, since the transmission region of the RMSI PDCCH is limited to one OFDM symbol #i-2, OFDM symbol #i-, which is the earliest symbol in the region of the RMSI PDSCH. At 1, the front-loaded DM-RS is transmitted. However, in the case of (b) of FIG. 10, since the transmission region of the RMSI PDCCH is set over two symbols composed of OFDM symbols #i-2 and #i-1, the RMSI PDSCH can be transmitted from OFDM symbol #i. have. In this case, when the front-loaded DM-RS for the RMSI PDSCH is transmitted in OFDM symbol #i, it may overlap with the transmission region of the SS/PBCH block.

FIG. 11 is a conceptual diagram illustrating methods of configuring a front-loaded DM-RS of an RMSI PDSCH when an RMSI PDCCH transmission region is configured as in FIG. 10.

In the case of (a) of FIG. 11, since the region of the RMSI PDCCH is set to only one OFDM symbol #i-2, the front-loaded DM-RS may be transmitted in the first symbol of the RMSI PDSCH, OFDM symbol #i-1.

On the other hand, in the case of (b) of FIG. 11, since the RMSI PDCCH transmission region is configured over OFDM symbols #i-2 and #i-1, the front-loaded DM-RS is the first symbol of the RMSI PDSCH, the OFDM symbol #i. Can be transmitted in. However, in this case, since the front-loaded DM-RS transmitted in OFDM symbol #i overlaps the transmission region of the SS/PBCH block, a method of solving this is required.

In the present invention, in order to solve the problem that the RMSI PDSCH DM-RS overlaps the transmission region of the SS/PBCH block, a method of using the RMSI PDCCH DM-RS for data demodulation of the RMSI PDSCH is proposed. The RMSI PDCCH containing scheduling information of the RMSI PDSCH is temporally transmitted in the preceding symbol of the RMSI PDSCH. If the DM-RS for the RMSI PDCCH is reused for data demodulation of the RMSI PDSCH, a separate DM-RS transmission for the RMSI PDSCH is not required, so resources can be used more efficiently.

12 is a conceptual diagram illustrating a case where an RMSI PDCCH DM-RS is shared with an RMSI PDSCH without a separate RMSI PDSCH DM-RS.

Referring to FIG. 12, the DM-RS of the RMSI PDCCH is shared with the RMSI PDSCH and the separate RMSI PDSCH DM-RS is not transmitted, thereby increasing resource efficiency. Since the RMSI PDCCH DM-RS is transmitted on all RMSI PDCCH symbols, when the RMSI PDCCH transmission region is set over OFDM symbols #i-2 and #i-1 as shown in Fig. 12(a), both symbols are RMSI PDCCH DMRS may be transmitted. As shown in (b) of FIG. 12, when the RMSI PDCCH transmission region is configured for only one OFDM symbol #i-1, the RMSI PDCCH DM-RS may be transmitted only for one OFDM symbol #i-1.

In general, a plurality of control information (ie, a plurality of PDCCHs) is multiplexed and transmitted in the transmission region of the PDCCH. Therefore, the DM-RS (PDCCH DM-RS) for demodulation of the control information of the PDCCH can be transmitted in two ways. That is, the transmission method of the PDCCH DM-RS is a method of transmitting the DM-RS only to a partial region in which control information of a specific PDCCH is transmitted within the transmission region of the entire PDCCH in which a plurality of control information is multiplexed and transmitted (narrow-band DM- RS) and a method of transmitting a DM-RS over the entire PDCCH transmission area (wide-band DM-RS). Since the RMSI PDCCH is also transmitted in a partial region in the transmission region of the entire PDCCH, if the DM-RS for the RMSI PDCCH is transmitted to the narrow-band DM-RS only in some regions, channel estimation for the remaining regions in which the DM-RS is not transmitted. Is not possible, and thus the PDCCH DM-RS cannot be used for data demodulation of the RMSI PDSCH transmitted to the corresponding region. Therefore, in the present invention, when the RMSI PDCCH DM-RS is shared for RMSI PDSCH data demodulation, a method of setting and transmitting the RMSI PDCCH DM-RS as a wide-band DM-RS transmitted over the entire PDCCH transmission region is applied. I can.

As another method, a method of transmitting the RMSI PDSCH DM-RS at the same symbol position as the PBCH DM-RS of the SS/PBCH block in the DRS rather than the first symbol of the PDSCH may be applied. When the RMSI PDSCH DM-RS is located in the same symbol as the PBCH DM-RS of the SS/PBCH block in the DRS, the channel estimation value of the region overlapping with the SS/PBCH block can be obtained through the PBCH DM-RS. Assuming the case of (b) of FIG. 11, channel estimation is performed using the PBCH DM-RS of the SS/PBCH block for the front-loaded DM-RS region that cannot be transmitted in the region overlapping with the SS/PBCH block. I can. However, compared to the method of obtaining a channel value by estimating each DM-RS mapped to different symbols and demodulating data, channel estimation and data demodulation are performed when the PBCH DM-RS and RMSI PDSCH DM-RS are mapped to the same symbol. There is an advantage that can be performed more simply. In addition, when channel estimation is performed by simultaneously utilizing two types of DM-RSs mapped to one symbol, a better channel estimation effect can be obtained, and a performance improvement effect can be obtained accordingly.

13 is a conceptual diagram illustrating a case of mapping the RMSI PDSCH DM-RS to the same symbol position as the PBCH DM-RS.

Referring to FIG. 13, in an SS/PBCH block transmitted over four symbols from OFDM symbols #i to #i+3, PBCH is 3 consisting of OFDM symbols #i+1, #i+2, and #i+3. It is transmitted in four symbols. Among them, in OFDM symbol #i+2, PBCH DM-RS is also transmitted only in some frequency domains in the SS/PBCH block. In the present invention, PBCH DM-RS and RMSI PDSCH DM- in OFDM symbol #i+1 or #i+3 We propose a method of sharing RS.

Figure 13 (a) shows a method of transmitting the RMSI PDSCH DM-RS in OFDM symbol #i+1 so that it is shared with the PBCH DM-RS transmitted in the corresponding symbol, Figure 13 (b) shows the RMSI PDSCH DM- This shows a method of transmitting an RS in OFDM symbol #i+3 so that it is shared with a PBCH DM-RS transmitted in a corresponding symbol. In order to obtain a better channel estimation effect by sharing the RMSI PDSCH DM-RS with the PBCH DM-RS or to reduce the complexity of implementation, it is necessary to match the RMSI PDSCH DM-RS configuration to the PBCH DM-RS. Therefore, in the present invention, in order to more efficiently share the RMSI PDSCH DM-RS with the PBCH DM-RS, the RMSI PDSCH DM-RS frequency mapping scheme is also the same as the PBCH DM-RS. We propose a method of increasing to 4 subcarriers. In addition, a method of mapping by applying a cell-specific frequency shift method in the same manner as the PBCH DM-RS is proposed. In addition, we propose a method of configuring the precoding granularity of the RMSI PDSCH to be applied to all allocated resources by applying the wideband. At this time, the position of the RMSI PDSCH DM-RS may be fixed to one of OFDM symbols #i+1 or #i+3, and one of the two values may be differently set according to circumstances. The information to be set at this time can be set through RMSI PDCCH control information, and as another method, it can be set through redefinition of front-loaded DM-RS information in the PBCH.

As another method, a method of transmitting the RMSI PDSCH DM-RS after the SS/PBCH block allocated symbol is proposed. When transmitting the RMSI PDSCH DM-RS after the SS/PBCH block, the problem of transmission region redundancy with the SS/PBCH block can be solved, and the RMSI PDSCH DM-RS configuration does not need to be adjusted to the configuration for PBCH DM-RS transmission. Can be set independently.

14 is a conceptual diagram illustrating a case in which an RMSI PDSCH DM-RS is transmitted after an SS/PBCH block transmission region.

Figure 14 (a) is a case where the RMSI PDSCH DM-RS is transmitted in the OFDM symbol #i+4 immediately after the SS/PBCH block transmission region, and Figure 14 (b) is the RMSI PDSCH DM-RS transmits the RMSI PDSCH This represents a case of transmission in OFDM symbol #i+5, which is the last symbol of the region. In a scheme in which the RMSI PDSCH DM-RS is transmitted after the SS/PBCH block transmission region so that the transmission region overlapping with the SS/PBCH block does not occur, the RMSI PDSCH DM-RS is located in a specific OFDM symbol after the transmission region of the SS/PBCH block. It is possible to do so and the exact location can be specified through signaling. Alternatively, in order to reduce signaling overhead, the RMSI PDSCH DM-RS may be transmitted in a fixed specific symbol such as a symbol immediately following the SS/PBCH block transmission region or the last symbol of the RMSI PDSCH transmission region. In this way, when the RMSI PDSCH DM-RS is transmitted in the rear part of the RMSI PDSCH transmission region after the SS/PBCH block transmission region, it is defined as'back-loaded DM-RS' to distinguish it from the existing front-loaded DM-RS. .

In the case of the back-loaded DM-RS, it can be transmitted regardless of the RMSI PDCCH transmission region, without the problem of overlapping the transmission region with the SS/PBCH block. You can't get an advantage. Accordingly, the present invention proposes a method of variably applying the front-loaded DM-RS and the back-loaded DM-RS according to the RMSI PDCCH transmission region configuration and the SS/PBCH block transmission region. That is, when the front-loaded DM-RS can transmit without overlapping the transmission region with the SS/PBCH block, the front-loaded DM-RS is transmitted, and when the SS/PBCH block and the transmission region overlap, the back-loaded DM -RS transmission method is possible. It is possible to dynamically inform whether a front-loaded DM-RS or a back-loaded DM-RS is transmitted using indication information (eg, 1-bit indication information) in the RMSI PDCCH control information. As another method, it is possible to inform whether a front-loaded DM-RS is transmitted or a back-loaded DM-RS is transmitted using indication information (eg, 1-bit indication information) in the PBCH content. As for the indication information in the PBCH content, indication information ( dmrs-TypeA-Position ) indicating the position of the front-loaded DM-RS described above may be substituted. As another method, a bit field in the PBCH content may be extended to signal various values including the position of the front-loaded DM-RS and the position of the back-loaded DM-RS in the DRS. As another method, the UE may determine whether the front-loaded DM-RS is implicitly transmitted or the back-loaded DM-RS is transmitted according to the RMSI PDCCH transmission region configuration and the SS/PBCH block transmission region.

In the embodiments of the present invention described above, that one DRS consists of 8 symbols is only an example for expressing the relative position of the SS/PBCH block in the DRS, and the number of symbols of 6, 7 or other Embodiments of the present invention may be applied to the DRS configured as.

RMSI PDSCH DM-RS and data multiplexing method during DRS transmission

In a symbol in which the PDSCH DM-RS is transmitted, data may or may not be transmitted in resource elements other than resource elements (REs) to which the DM-RS is mapped. This varies depending on whether the PDCCH format or higher layer signaling is received. In the existing Rel-15 NR, PDSCH data is not transmitted in a symbol in which RMSI PDSCH DM-RS is transmitted according to the above condition.

However, in the case of the NR-U system, whether or not the DRS can be transmitted is determined according to the success of the LBT operation, and the DRS transmission is possible only for a limited time even when the LBT operation is successful, so it is necessary to use resources as efficiently as possible. Also, in the case of NR-U in general, since the cell radius is not large, it may not be necessary to apply power boosting to the DM-RS. Therefore, in order to use resources more efficiently, the present invention proposes a method of mapping and transmitting RMSI PDSCH data in RMSI PDSCH DM-RS transmission symbols in an NR-U environment.

In this case, since more resources for RMSI PDSCH data transmission can be secured, RMSI reception performance can be improved. However, even in an NR-U environment, it may be more advantageous to increase the channel estimation performance by applying power boosting to the RMSI PDSCH DM-RS. Accordingly, the present invention proposes a method of configuring whether RMSI PDSCH data is mapped in the RMSI PDSCH DM-RS transmission symbol. By variably setting whether to map RMSI PDSCH data in the RMSI PDSCH DM-RS transmission symbol, the NR-U system can be more adaptively and efficiently configured to suit the environment. This configuration can be set through RMSI PDCCH control information or through system information in PBCH content.

15 is a conceptual diagram for comparing RMSI PDSCH data mapping of an NR system and RMSI PDSCH data mapping of an NR-U system.

15A is a case of an existing Rel-15 NR system, and RMSI PDSCH data other than the DM-RS is not mapped to a symbol to which the RMSI PDSCH DM-RS is mapped in the RMSI PDSCH transmission region. However, (b) of FIG. 15 is a case of an NR-U system according to an embodiment of the present invention, and resources can be more efficiently used by mapping RMSI PDSCH data to symbols to which RMSI PDSCH DM-RS is mapped. .

Device configuration according to the invention

16 is a block diagram illustrating a communication node according to embodiments of the present invention.

The communication node illustrated in FIG. 16 may be a terminal or a base station as an apparatus capable of executing methods according to embodiments of the present invention.

Referring to FIG. 16, a communication node 1600 may include at least one processor 1610, a memory 1620, and a transmission/reception device 1630 connected to a network to perform communication. In addition, the communication node 1600 may further include an input interface device 1640, an output interface device 1650, a storage device 1660, and the like. Each of the components included in the communication node 1600 may be connected by a bus 1670 to perform communication with each other.

However, each of the components included in the communication node 1600 may be connected through an individual interface or an individual bus centered on the processor 1610 instead of the common bus 1670. For example, the processor 1610 may be connected to at least one of the memory 1620, the transceiver 1630, the input interface device 1640, the output interface device 1650, and the storage device 1660 through a dedicated interface. .

The processor 1610 may execute a program command stored in at least one of the memory 1620 and the storage device 1660. The processor 1610 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which methods according to embodiments of the present invention are performed. Each of the memory 1620 and the storage device 1660 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 1620 may be formed of at least one of a read only memory (ROM) and a random access memory (RAM).

Embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes such as those created by a compiler. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (1)

As an operating method of a terminal receiving a discovery recovery signal (DRS),
Receiving a first DRS from a base station;
Determining the number of DRSs configured in one slot based on indication information included in the PBCH of a synchronization signal/physical broadcast channel (SS/PBCH) block included in the first DRS;
When it is determined that one DRS is configured in one slot, a resource configuration method of a physical downlink shared channel (PDSCH) for reception of RMSI (remaining system information) included in the first DRS is determined as type A, and one Determining a resource configuration method of the PDSCH as type B when it is determined that two or more DRSs are configured in the slot; And
Including the step of receiving the PDSCH according to the determined resource setting method,
Terminal operation method.

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