KR20230138417A - Method and apparatus for transmitting and receiving nr(new radio technology) pdcch(physical downlink control channel) in mobile communication system - Google Patents

Abstract

Provided are a method and device for transmitting and receiving a new radio technology (NR) physical downlink control channel (PDCCH) in a wireless communication system. In one or more orthogonal frequency division multiplexing (OFDM) symbols within a slot, the terminal monitors a physical downlink control channel (PDCCH) transmitted by the base station, where the slot is a long term evolution (LTE) cell-specific reference signal (CRS). It is used for, and the terminal receives a demodulation reference signal (DM-RS) for decoding the PDCCH from the base station in at least one OFDM symbol in the slot. Here, the RE (resource element) used in DM-RS for decoding PDCCH does not overlap with the RE used in long term evolution (LTE) CRS.

Description

Method and device for transmitting and receiving NR (new radio technology) PDCCH (physical downlink control channel) in a wireless communication system }

This specification relates to the 3GPP 5G NR system.

As more and more communication devices require larger communication traffic with the passage of time, the next-generation 5G system, which is an improved wireless broadband communication system than the existing LTE system, is required. In this next-generation 5G system, called NewRAT, communication scenarios are divided into Enhanced Mobile BroadBand (eMBB) / Ultra-reliability and low-latency communication (URLLC) / Massive Machine-Type Communications (mMTC).

Here, eMBB is a next-generation mobile communication scenario with characteristics such as High Spectrum Efficiency, High User Experienced Data Rate, and High Peak Data Rate, and URLLC is a next-generation mobile communication scenario with characteristics such as Ultra Reliable, Ultra Low Latency, and Ultra High Availability. (e.g., V2X, Emergency Service, Remote Control), mMTC is a next-generation mobile communication scenario with Low Cost, Low Energy, Short Packet, and Massive Connectivity characteristics. (e.g., IoT).

The present disclosure seeks to provide a method and apparatus for transmitting and receiving a new radio technology (NR) physical downlink control channel (PDCCH) in a wireless communication system.

An embodiment of the present specification is a wireless communication system, where a terminal monitors a new radio technology (NR) physical downlink control channel (PDCCH) in one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols within a slot, where the slot is LTE (long term evolution) is used for a cell-specific reference signal (CRS), and a demodulation reference signal (DM-RS) for decoding of the PDCCH is received in at least one OFDM symbol in a slot, and a DM-RS for decoding of the PDCCH is received. The RE (resource element) used in RS provides a method that does not overlap with the RE used in LTE CRS.

In addition, in an embodiment of the present invention, in a wireless communication system, a base station configures one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a slot for new radio technology (NR) PDCCH transmission, where the slot is LTE (long term evolution) is used for a cell-specific reference signal (CRS), and allocates a demodulation reference signal (DM-RS) for decoding of the PDCCH to at least one OFDM symbol in a slot, and DM- for decoding the PDCCH and the PDCCH. The RE (resource element) used in DM-RS for transmitting RS and decoding PDCCH provides a method that does not overlap with the RE used in LTE CRS.

Additionally, embodiments of the present invention include, in a wireless communication system, at least one processor, and at least one memory that stores instructions and is operably electrically connectable to the at least one processor. , based on which instructions are executed by at least one processor, the operations performed are:

A new radio technology (NR) physical downlink control channel (PDCCH) is monitored in one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols within a slot, where the slot is a long term evolution (LTE) cell-specific reference signal (CRS). ), and a DM-RS (demodulation reference signal) for decoding of the PDCCH is received from at least one OFDM symbol in the slot, and the RE (resource element) used for the DM-RS for decoding of the PDCCH is LTE Provides communication devices that do not overlap with RE used in CRS.

Additionally, embodiments of the present invention include, in a wireless communication system, at least one processor, and at least one memory that stores instructions and is operably electrically connectable to the at least one processor. , Based on which instructions are executed by at least one processor, the operations performed are: one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a slot for new radio technology (NR) physical downlink control channel (PDCCH) transmission; Configures, where the slot is used for a long term evolution (LTE) cell-specific reference signal (CRS), and a demodulation reference signal (DM-RS) for decoding of the PDCCH is transmitted to at least one OFDM symbol in the slot. Allocates and transmits a PDCCH and a DM-RS for decoding of the PDCCH, and the RE (resource element) used for the DM-RS for decoding of the PDCCH provides a base station that does not overlap with the RE used for LTE CRS. .

Additionally, an embodiment of the present invention is a computer-readable storage medium that records instructions, which, when executed by one or more processors, cause the one or more processors to: ) monitor a new radio technology (NR) physical downlink control channel (PDCCH) in a symbol, where the slot is used for a long term evolution (LTE) cell-specific reference signal (CRS), and for decoding of the PDCCH A demodulation reference signal (DM-RS) is received in at least one OFDM symbol within the slot, and a resource element (RE) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS. Provides storage media.

When symbols including LTE CRS and symbols not including LTE CRS are mixed in a plurality of OFDM symbols for which the UE monitors the PDCCH, at least one OFDM symbol receiving a DM-RS for decoding the PDCCH is LTE CRS may not include.

Meanwhile, when symbols including LTE CRS and symbols not including LTE CRS are mixed in a plurality of OFDM symbols for PDCCH transmission from the base station, DM-RS for decoding of PDCCH does not include the LTE CRS. Only the at least one OFDM symbol that is not transmitted is transmitted, and the terminal can receive it.

And, DM-RS puncturing can be applied to RE used in LTE CRS.

In addition, the configuration information of the LTE CRS can be transmitted and received through radio resource control (RRC) signaling, and the configuration information of the LTE CRS sets the rate matching pattern of the LTE CRS for the PDCCH. It could be information.

According to the disclosure of this specification, a new radio technology (NR) physical downlink control channel (PDCCH) can be efficiently transmitted and received in a wireless mobile communication system.

1 is a diagram illustrating a wireless communication system.
Figure 2 illustrates the structure of a radio frame used in NR.
3A to 3C are diagrams illustrating an exemplary architecture for next-generation mobile communication services.
Figure 4 illustrates the slot structure of an NR frame.
Figure 5 shows examples of subframe types in NR.
Figure 6 illustrates the structure of a self-contained slot.
Figure 7 illustrates cross-carrier scheduling in a carrier aggregation system.
Figure 8 shows an example of dynamic spectrum sharing (DSS) technology.
9 to 11 show some examples of CRS structures when using more than one antenna.
Figure 12 is a diagram showing an example of the structure of a 5G NR PDCCH.
Figure 13 shows a method of operating a terminal according to an embodiment of the present specification.
Figure 14 shows a method of operating a base station according to an embodiment of the present specification.
Figure 15 shows a device according to an embodiment of the present specification.
Figure 16 is a block diagram showing the configuration of a terminal according to an embodiment of the present specification.
Figure 17 shows a configuration block diagram of a processor on which the disclosure of the present specification is implemented.
FIG. 18 is a block diagram showing in detail the transceiver of the first device shown in FIG. 15 or the transceiver unit of the device shown in FIG. 16.

It should be noted that the technical terms used in this specification are only used to describe specific embodiments and are not intended to limit the content of this specification. In addition, technical terms used in this specification, unless specifically defined in a different way in this specification, should be interpreted as meanings generally understood by those skilled in the art in the technical field to which the disclosure of this specification pertains. It should not be interpreted in a very comprehensive sense or in an excessively reduced sense. Additionally, if the technical terms used in this specification are incorrect technical terms that do not accurately express the content and idea of the present specification, they should be replaced with technical terms that can be correctly understood by those skilled in the art. Additionally, general terms used in this specification should be interpreted as defined in the dictionary or according to the context, and should not be interpreted in an excessively reduced sense.

Additionally, as used herein, singular expressions include plural expressions, unless the context clearly dictates otherwise. In this application, terms such as constitute or have should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or steps may not be included. , or it should be interpreted that it may further include additional components or steps.

Additionally, terms including ordinal numbers, such as first, second, etc., used in this specification may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component without departing from the scope of rights, and similarly, the second component may also be named a first component.

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

Hereinafter, the embodiment will be described in detail with reference to the attached drawings, but identical or similar components will be assigned the same reference numbers regardless of the reference numerals, and duplicate descriptions thereof will be omitted. Additionally, in explaining the contents of this specification, if it is determined that a detailed description of related known technology may obscure the gist of the present specification, the detailed description will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the content and idea of the present specification, and should not be construed as limiting the content and idea of the present specification by the attached drawings. The content and ideas of this specification should be construed as extending to all changes, equivalents, or substitutes other than the attached drawings.

As used herein, “A or B” may mean “only A,” “only B,” or “both A and B.” In other words, in this specification, “A or B” may be interpreted as “A and/or B.” For example, as used herein, “A, B or C” means “only A,” “only B,” “only C,” or “any and all combinations of A, B, and C ( It can mean “any combination of A, B and C)”.

The slash (/) or comma used in this specification may mean “and/or.” For example, “A/B” can mean “A and/or B.” Accordingly, “A/B” can mean “only A,” “only B,” or “both A and B.” For example, “A, B, C” can mean “A, B, or C.”

As used herein, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” In addition, in this specification, the expression “at least one of A or B” or “at least one of A and/or B” means “at least one It can be interpreted the same as “at least one of A and B.”

In addition, as used herein, “at least one of A, B and C” means “only A”, “only B”, “only C”, or “A, B and C”. It can mean “any combination of A, B and C.” In addition, “at least one of A, B or C” or “at least one of A, B and/or C” means It may mean “at least one of A, B and C.”

Additionally, parentheses used in this specification may mean “for example.” Specifically, when “control information (PDCCH)” is indicated, “PDCCH (Physical Downlink Control Channel)” may be proposed as an example of “control information.” In other words, “control information” in this specification is not limited to “PDCCH,” and “PDDCH” may be proposed as an example of “control information.” Additionally, even when “control information (i.e., PDCCH)” is indicated, “PDCCH” may be proposed as an example of “control information.”

Technical features described individually in one drawing in this specification may be implemented individually or simultaneously.

In the attached drawings, a UE (User Equipment) is shown as an example, but the illustrated UE may also be referred to by terms such as terminal, ME (mobile equipment), etc. Additionally, the UE may be a portable device such as a laptop, mobile phone, PDA, smart phone, or multimedia device, or may be a non-portable device such as a PC or vehicle-mounted device.

Hereinafter, UE is used as an example of a device capable of wireless communication (e.g., wireless communication device, wireless device, or wireless device). Operations performed by the UE may be performed by any device capable of wireless communication. A device capable of wireless communication may also be referred to as a wireless communication device, wireless device, or wireless device.

The term base station used below generally refers to a fixed station that communicates with wireless devices, including eNodeB (evolved-NodeB), eNB (evolved-NodeB), BTS (Base Transceiver System), and access point ( It can be used as a comprehensive term including Access Point), gNB (Next generation NodeB), RRH (remote radio head), TP (transmission point), RP (reception point), relay, etc.

Although this specification describes embodiments using an LTE system, an LTE-A system, and an NR system, these embodiments may be applied to any communication system that falls within the above definition.

<Next generation mobile communication network>

Thanks to the success of LTE (long term evolution)/LTE-Advanced (LTE-A) for 4th generation mobile communication, commercialization of the next generation, that is, 5th generation (so-called 5G) mobile communication, has been completed and follow-up research is continuing. .

The 5th generation mobile communication, as defined by the International Telecommunication Union (ITU), refers to providing a data transmission speed of up to 20Gbps and an experienced transmission speed of at least 100Mbps anywhere. The official name is referred to as ‘IMT-2020’.

ITU proposes three major usage scenarios, such as enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliable and Low Latency Communications (URLLC).

URLLC addresses usage scenarios that require high reliability and low latency. For example, services such as autonomous driving, factory automation, and augmented reality require high reliability and low latency (e.g., latency of less than 1 ms). The current 4G (LTE) latency is statistically 21-43ms (best 10%), 33-75ms (median). This is insufficient to support services requiring latency of 1ms or less. Next, the eMBB usage scenario concerns a usage scenario requiring mobile ultra-wideband.

In other words, the 5th generation mobile communication system supports higher capacity than 4G LTE, increases the density of mobile broadband users, and can support D2D (Device to Device), high stability, and MTC (Machine type communication). 5G research and development also targets lower latency and lower battery consumption than 4G mobile communication systems to better implement the Internet of Things. For such 5G mobile communication, a new radio access technology (New RAT or NR) may be proposed.

The NR frequency band can be defined as two types of frequency ranges (FR1, FR2). The values of the frequency range may be changed. For example, the frequency ranges of the two types (FR1, FR2) may be as shown in Table 1 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean “sub 6GHz range,” and FR2 may mean “above 6GHz range” and may be called millimeter wave (mmW). .

Frequency Range designation Corresponding frequency range Subcarrier Spacing FR1 410MHz - 7125MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240kHz

The values of the frequency range of the NR system may vary. For example, FR1 may include a band from 410MHz to 7125MHz as shown in Table 1. That is, FR1 may include a frequency band of 6GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include an unlicensed band. Unlicensed bands can be used for a variety of purposes, for example, for communications for vehicles (e.g., autonomous driving).

Meanwhile, the 3GPP-based communication standard includes downlink physical channels corresponding to resource elements that carry information originating from the upper layer, and resource elements that are used by the physical layer but do not carry information originating from the upper layer. Downlink physical signals are defined. For example, a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), a physical multicast channel (PMCH), and a physical control format indicator channel (physical control). format indicator channel (PCFICH), physical downlink control channel (PDCCH), and physical hybrid ARQ indicator channel (PHICH) are defined as downlink physical channels, and reference signals and synchronization signals are defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal with a predefined special waveform known to both the gNB and the UE, for example, cell specific RS (cell specific RS), UE- UE-specific RS (UE-RS), positioning RS (PRS), and channel state information RS (CSI-RS) are defined as downlink reference signals. The 3GPP LTE/LTE-A standard corresponds to uplink physical channels corresponding to resource elements carrying information originating from upper layers, and resource elements used by the physical layer but not carrying information originating from upper layers. Uplink physical signals are defined. For example, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH) are used as uplink physical channels. A demodulation reference signal (DMRS) for uplink control/data signals and a sounding reference signal (SRS) used for uplink channel measurement are defined.

In this specification, PDCCH (Physical Downlink Control CHannel) / PCFICH (Physical Control Format Indicator CHannel) / PHICH ((Physical Hybrid automatic retransmit request Indicator CHannel) / PDSCH (Physical Downlink Shared CHannel) are respectively DCI (Downlink Control Information) / CFI ( Control Format Indicator)/Downlink ACK/NACK (ACKnowlegement/Negative ACK)/Refers to a set of time-frequency resources or a set of resource elements carrying downlink data. Also, PUCCH (Physical Uplink Control CHannel)/PUSCH (Physical Uplink Shared CHannel)/PRACH (Physical Random Access CHannel) refers to a set of time-frequency resources or a set of resource elements that carry UCI (Uplink Control Information)/uplink data/random access signal, respectively.

1 is a diagram illustrating a wireless communication system.

As can be seen with reference to FIG. 1, a wireless communication system includes at least one base station (BS). The BS is divided into gNodeB (or gNB) 20a and eNodeB (or eNB) 20b. The gNB (20a) supports 5th generation mobile communication. The eNB (20b) supports 4th generation mobile communication, that is, long term evolution (LTE).

Each base station 20a and 20b provides communication services for a specific geographic area (generally referred to as a cell) 20-1, 20-2, and 20-3. A cell can be further divided into multiple areas (referred to as sectors).

A user equipment (UE) usually belongs to one cell, and the cell to which the UE belongs is called a serving cell. A base station that provides communication services to a serving cell is called a serving BS. Since the wireless communication system is a cellular system, there are other cells adjacent to the serving cell. Other cells adjacent to the serving cell are called neighboring cells. A base station that provides communication services to a neighboring cell is called a neighboring base station (neighbor BS). The serving cell and neighboring cells are determined relatively based on the UE.

Hereinafter, downlink refers to communication from the base station 20 to the UE 10, and uplink refers to communication from the UE 10 to the base station 20. In the downlink, the transmitter may be part of the base station 20 and the receiver may be part of the UE 10. In the uplink, the transmitter may be part of the UE 10 and the receiver may be part of the base station 20.

Meanwhile, wireless communication systems can be broadly divided into FDD (frequency division duplex) and TDD (time division duplex) methods. According to the FDD method, uplink transmission and downlink transmission occur while occupying different frequency bands. According to the TDD method, uplink transmission and downlink transmission occupy the same frequency band and occur at different times. The channel response of the TDD method is substantially reciprocal. This means that in a given frequency region, the downlink channel response and the uplink channel response are almost identical. Therefore, in a wireless communication system based on TDD, there is an advantage that the downlink channel response can be obtained from the uplink channel response. In the TDD method, uplink transmission and downlink transmission are time-divided over the entire frequency band, so downlink transmission by the base station and uplink transmission by the UE cannot be performed simultaneously. In a TDD system in which uplink transmission and downlink transmission are separated on a subframe basis, uplink transmission and downlink transmission are performed in different subframes.

Figure 2 illustrates the structure of a radio frame used in NR.

In NR, uplink and downlink transmission consists of frames. A wireless frame is 10ms long and is defined as two 5ms half-frames (HF). A half-frame is defined as five 1ms subframes (Subframe, SF). A subframe is divided into one or more slots, and the number of slots in a subframe depends on SCS (Subcarrier Spacing). Each slot contains 12 or 14 OFDM(A) symbols depending on the cyclic prefix (CP). When regular CP is used, each slot contains 14 symbols. When extended CP is used, each slot contains 12 symbols. Here, the symbol may include an OFDM symbol (or CP-OFDM symbol) and an SC-FDMA symbol (or DFT-s-OFDM symbol).

<Support for various numerologies>

In the NR system, as wireless communication technology develops, multiple numerologies may be provided to the terminal. For example, if SCS is 15kHz, it supports wide area in traditional cellular bands, and if SCS is 30kHz/60kHz, it supports dense-urban, lower latency. And it supports a wider carrier bandwidth, and when SCS is 60kHz or higher, it supports a bandwidth greater than 24.25GHz to overcome phase noise.

The numerology can be defined by CP (cycle prefix) length and subcarrier spacing (SCS). One cell can provide multiple numerologies to a terminal. When the index of numerology is expressed as μ, each subcarrier spacing and the corresponding CP length can be as shown in the table below.

μ △f=2 ^μ 15 [kHz] CP 0 15 common One 30 common 2 60 General, extended 3 120 common 4 240 common 5 480 common 6 960 common

In the case of general CP, when the index of numerology is expressed as μ, the number of OFDM symbols per slot (N ^slot _symb ), the number of slots per frame (N ^frame,μ _slot ), and the number of slots per subframe (N ^subframe,μ _slot ) is as shown in the table below.

μ △f=2 ^μ 15 [kHz] N- ^slot _symbol N ^{frame, μ} _slot N ^{subframe, μ} _slot 0 15 14 10 One One 30 14 20 2 2 60 14 40 4 3 120 14 80 8 4 240 14 160 16 5 480 14 320 32 6 960 14 640 64

In the case of extended CP, when the index of numerology is expressed as μ, the number of OFDM symbols per slot (N ^slot _symb ), the number of slots per frame (N ^frame,μ _slot ), and the number of slots per subframe (N ^subframe,μ _slot ) is as shown in the table below.

μ SCS (15* ^2u ) N- ^slot _symbol N ^{frame, μ} _slot N ^{subframe, μ} _slot 2 60KHz (u=2) 12 40 4

In the NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) may be set differently between a plurality of cells merged into one UE. Accordingly, the (absolute time) interval of time resources (e.g., SF, slot, or TTI) (for convenience, collectively referred to as TU (Time Unit)) consisting of the same number of symbols may be set differently between merged cells.

3A to 3C are illustrative diagrams showing an example architecture for wireless communication services.

Referring to FIG. 3A, the UE is connected to an LTE/LTE-A-based cell and an NR-based cell in a dual connectivity (DC) manner.

The NR-based cell is connected to the existing core network for 4th generation mobile communication, that is, EPC (Evolved Packet Core).

Referring to Figure 3b, unlike Figure 3a, the LTE/LTE-A based cell is connected to the core network for 5th generation mobile communication, that is, the 5G core network.

A service method based on the architecture shown in FIGS. 3A and 3B above is called NSA (non-standalone).

Referring to Figure 3c, the UE is connected only to NR-based cells. The service method based on this architecture is called SA (standalone).

Meanwhile, in the NR, it may be considered that reception from the base station uses a downlink subframe, and transmission to the base station uses an uplink subframe. This method can be applied to paired and unpaired spectra. A pair of spectrum means that it contains two carrier spectra for downlink and uplink operations. For example, in a pair of spectrum, one carrier may include a downlink band and an uplink band that are paired with each other.

Figure 4 illustrates the slot structure of the NR frame.

A slot includes a plurality of symbols in the time domain. For example, in the case of a general CP, one slot includes 14 symbols, but in the case of an extended CP, one slot includes 12 symbols. A carrier wave includes a plurality of subcarriers in the frequency domain. RB (Resource Block) is defined as multiple (eg, 12) consecutive subcarriers in the frequency domain. BWP (Bandwidth Part) is defined as a plurality of consecutive (physical, P)RBs in the frequency domain and may correspond to one numerology (e.g., SCS, CP length, etc.). The terminal can configure up to N (e.g., 4) BWPs in the downlink and uplink. Downlink or uplink transmission is performed through an activated BWP, and at a given time, only one BWP among the BWPs configured for the terminal can be activated. Each element in the resource grid is referred to as a Resource Element (RE), and one complex symbol can be mapped.

Figure 5 shows examples of subframe types in NR.

The transmission time interval (TTI) shown in FIG. 5 may be called a subframe or slot for NR (or new RAT). The subframe (or slot) of FIG. 5 can be used in a TDD system of NR (or new RAT) to minimize data transmission delay. As shown in Figure 5, a subframe (or slot) includes 14 symbols. The first symbol of a subframe (or slot) can be used for a downlink (DL) control channel, and the last symbol of a subframe (or slot) can be used for an uplink (UL) control channel. The remaining symbols can be used for DL data transmission or UL data transmission. According to this subframe (or slot) structure, downlink transmission and uplink transmission can proceed sequentially in one subframe (or slot). Accordingly, downlink data may be received within a subframe (or slot), and an uplink acknowledgment (ACK/NACK) may be transmitted within the subframe (or slot).

This subframe (or slot) structure may be referred to as a self-contained subframe (or slot).

Specifically, the first N symbols in a slot can be used to transmit a DL control channel (hereinafter, DL control area), and the last M symbols in a slot can be used to transmit a UL control channel (hereinafter, UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as data area) between the DL control area and the UL control area may be used for DL data transmission or may be used for UL data transmission. For example, a physical downlink control channel (PDCCH) may be transmitted in the DL control area, and a physical downlink shared channel (PDSCH) may be transmitted in the DL data area. A physical uplink control channel (PUCCH) may be transmitted in the UL control area, and a physical uplink shared channel (PUSCH) may be transmitted in the UL data area.

Using this subframe (or slot) structure has the advantage of minimizing the final data transmission waiting time by reducing the time it takes to retransmit data with reception errors. In such a self-contained subframe (or slot) structure, a time gap may be required in the transition process from transmission mode to reception mode or from reception mode to transmission mode. To this end, some OFDM symbols when switching from DL to UL in the subframe structure can be set to a guard period (GP).

Figure 6 illustrates the structure of a self-contained slot.

In the NR system, a frame features a self-contained structure in which a DL control channel, DL or UL data, and UL control channel can all be included in one slot. For example, the first N symbols in a slot may be used to transmit a DL control channel (hereinafter, DL control area), and the last M symbols in a slot may be used to transmit a UL control channel (hereinafter, UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as data area) between the DL control area and the UL control area may be used for DL data transmission or may be used for UL data transmission. As an example, the following configuration may be considered. Each section is listed in chronological order.

1. DL only configuration

2. UL only configuration

3. Mixed UL-DL configuration

- DL area + GP (Guard Period) + UL control area

- DL control area + GP + UL area

DL area: (i) DL data area, (ii) DL control area + DL data area

UL area: (i) UL data area, (ii) UL data area + UL control area

PDCCH may be transmitted in the DL control area, and PDSCH may be transmitted in the DL data area. PUCCH may be transmitted in the UL control area, and PUSCH may be transmitted in the UL data area. In the PDCCH, Downlink Control Information (DCI), for example, DL data scheduling information, UL data scheduling information, etc. may be transmitted. In PUCCH, Uplink Control Information (UCI), for example, Positive Acknowledgment/Negative Acknowledgment (ACK/NACK) information for DL data, Channel State Information (CSI) information, Scheduling Request (SR), etc. may be transmitted. GP provides a time gap during the process of the base station and the terminal switching from transmission mode to reception mode or from reception mode to transmission mode. Some symbols at the point of transition from DL to UL within a subframe may be set to GP.

<Carrier Aggregation (CA)>

The system frequency band of a wireless communication system is divided into a plurality of carrier frequencies. Here, the carrier frequency means the center frequency of a cell.

Now, the carrier aggregation system will be described.

A carrier aggregation system means aggregating multiple component carriers (CC). Due to such carrier aggregation, the meaning of an existing cell may be changed. According to carrier aggregation, a cell may mean a combination of a downlink component carrier and an uplink component carrier, or a single downlink (or uplink) component carrier.

Additionally, in carrier aggregation, serving cells can be divided into primary cells and secondary cells. A primary cell refers to a cell operating at a primary frequency, a cell in which a UE performs an initial connection establishment procedure or connection re-establishment procedure with a base station, or a cell indicated as a primary cell in the handover process. means. A secondary cell refers to a cell that operates at a secondary frequency and is used to provide additional radio resources once a radio resource control (RRC) connection is established.

This carrier aggregation system can support cross-carrier scheduling. Cross-carrier scheduling refers to resource allocation of PDSCH transmitted through another component carrier through a PDCCH transmitted through a specific component carrier and/or other elements other than the component carrier that is basically linked to the specific component carrier. This is a scheduling method that can allocate resources for PUSCH transmitted through a carrier wave. That is, the PDCCH and PDSCH may be transmitted through different downlink CCs, and the PUSCH may be transmitted through an uplink CC other than the uplink CC linked to the downlink CC on which the PDCCH including the UL grant is transmitted. . In a system that supports cross-carrier scheduling like this, a carrier indicator is needed to indicate through which DL CC/UL CC the PDSCH/PUSCH, on which the PDCCH provides control information, is transmitted. The field containing this carrier indicator is hereinafter referred to as a carrier indication field (CIF).

A carrier aggregation system that supports cross-carrier scheduling may include a carrier indication field (CIF) in the conventional downlink control information (DCI) format. A system that supports cross-carrier scheduling For example, in the LTE-A system, CIF is added to the existing DCI format (i.e., the DCI format used in LTE), so 3 bits can be extended, and the PDCCH structure can be extended by using the existing coding method. , resource allocation methods (i.e., CCE-based resource mapping), etc. can be reused.

Figure 7 illustrates cross-carrier scheduling in a carrier aggregation system.

Referring to FIG. 7, the base station can set a PDCCH monitoring DL CC (monitoring CC) set. The PDCCH monitoring DL CC set consists of some DL CCs among all aggregated DL CCs, and when cross-carrier scheduling is set, the UE performs PDCCH monitoring/decoding only for DL CCs included in the PDCCH monitoring DL CC set. In other words, the base station transmits the PDCCH for the PDSCH/PUSCH to be scheduled only through the DL CC included in the PDCCH monitoring DL CC set. The PDCCH monitoring DL CC set can be configured as UE-specific, UE group-specific, or cell-specific.

Figure 7 shows an example in which three DL CCs (DL CC A, DL CC B, and DL CC C) are aggregated, and DL CC A is set as the PDCCH monitoring DL CC. The UE can receive scheduling information (i.e., DCI including a DL grant) for the PDSCHs of DL CC A, DL CC B, and DL CC C through the PDCCH of DL CC A. The DCI transmitted through the PDCCH of DL CC A may include a CIF to indicate which DL CC the DCI is for.

<DSS (Dynamic Spectrum Sharing) technology>

The 5G wireless mobile communication system NR defined by 3GPP supports DSS (Dynamic Spectrum Sharing), a frequency sharing technology for coexistence with LTE.

Figure 8 shows an example of DSS technology.

As shown in Figure 8, according to DSS technology, the carrier operated by the LTE/LTE-A base station can be dynamically shared by the 5G NR base station.

LTE/LTE-A base stations use radio resources based on a subcarrier spacing (SCS) of 15 kHz. That is, one RB defined on the frequency axis uses 12 subcarriers, and a transmission time interval (TTI) defined on the time axis uses subframes.

For coexistence with LTE/LTE-A-based systems (i.e., eNodeB and UE), DSS technology uses a subcarrier spacing (SCS) of 15 kHz, which is used to define one RB on the frequency axis, to 5G NR-based systems (i.e., gNB). and terminal) should be used as is. A subframe, a resource unit on the time axis used in LTE/LTE-A based systems, is used as one slot in the 5G NR system.

Meanwhile, in the LTE/LTE-A system, CRS (Cell-specific Reference Signal) is transmitted in the downlink. Hereinafter, CRS will be described.

9 to 11 show some examples of CRS structures when using more than one antenna.

Specifically, Figure 9 shows the CRS structure when the base station uses one antenna, Figure 10 shows the case when the base station uses two antennas, and Figure 11 shows the CRS structure when the base station uses four antennas.

Referring to FIGS. 9 to 11, in the case of multi-antenna transmission in which a base station uses multiple antennas, there is one resource grid for each antenna. 'R0' represents a reference signal for the first antenna, 'R1' represents a reference signal for the second antenna, 'R2' represents a reference signal for the third antenna, and 'R3' represents a reference signal for the fourth antenna. The positions within the subframes of R0 to R3 do not overlap with each other. ℓ is the position of the OFDM symbol within the slot, and in general CP, ℓ has a value between 0 and 6. In one OFDM symbol, the reference signal for each antenna is located at 6 subcarrier intervals. The number of R0 and R1 in the subframe are the same, and the number of R2 and R3 are the same. The number of R2 and R3 in the subframe is less than the number of R0 and R1. Resource elements used in the reference signal of one antenna are not used in the reference signal of another antenna. This is to avoid interference between antennas.

CRS is always transmitted as many times as the number of antennas, regardless of the number of streams. CRS has an independent reference signal for each antenna. The location of the frequency domain and the location of the time domain within the CRS subframe are determined regardless of the terminal. The CRS sequence that is multiplied by the CRS is also generated regardless of the terminal. Therefore, all UEs in the cell can receive CRS. However, the location of the CRS subframe and the CRS sequence may be determined according to the cell ID. The position in the time domain within the CRS subframe can be determined according to the number of the antenna and the number of OFDM symbols in the resource block. The location of the frequency domain within the CRS subframe may be determined according to the antenna number, cell ID, OFDM symbol index (ℓ), slot number within the radio frame, etc.

The CRS sequence can be applied on an OFDM symbol basis within one subframe. The CRS sequence may vary depending on the cell ID, slot number within one radio frame, OFDM symbol index within the slot, type of CP, etc. In one OFDM symbol, the number of reference signal subcarriers for each antenna is two. Assuming that a subframe includes N _RB resource blocks in the frequency domain, the number of reference signal subcarriers for each antenna in one OFDM symbol is 2×N _RB .

CRS can be used to estimate Channel State Information (CSI) in the LTE-A system. Through estimation of CSI, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), etc. can be reported from the terminal when necessary.

Figure 12 is a diagram illustrating an example of the structure of a 5G NR PDCCH.

In Figure 12, an example in which two BWPs (BWP #1, BWP #2) are set within the system bandwidth on the frequency axis, and two PDCCH CORESETs (control resource sets) are set within one slot on the time axis. shows. CORESET can be allocated continuously or discontinuously on the frequency axis, and 1 to 3 OFDM symbols can be allocated on the time axis. Referring to the example shown in FIG. 12, one OFDM symbol is allocated to the PDCCH CORESET set in BWP #1, and 3 OFDM symbols are allocated to the PDCCH CORESET set in BWP #2.

Meanwhile, in 5G NR, PDCCH can be allocated on a CCE (control channel element) basis. 1 CCE is composed of 6 REGs (resource element group), and 1 REG is composed of 12 REs (resource elements), which is 1 PRB (physical resource block), that is, 12 subcarriers on the frequency axis and 1 OFDM symbol on the time axis. It can be defined as: REG consists of REs to which DCI (downlink control information) is mapped and REs to which DM-RS for decoding it is mapped. As shown in FIG. 12, three DM-RSs can be set within 1 REG.

<Problems that the disclosure of this specification seeks to solve>

The 5G wireless mobile communication system NR defined by 3GPP supports dynamic spectrum sharing (DSS), a frequency sharing technology for coexistence with LTE. In other words, it is a method to efficiently migrate any LTE frequency band and utilize it as an NR frequency band in the future, transmitting NR signals by utilizing the remaining resources excluding the radio resources used for LTE signal transmission in the corresponding frequency band. It was defined to support DSS technology for use. For example, when transmitting PDSCH, a downlink data channel, any NR base station sets a rate match pattern for LTE CRS in order to transmit PDSCH through REs (Resource Elements) other than those used for LTE CRS transmission. It has been defined as possible.

However, in the case of PDCCH for transmitting Downlink Control Information (DCI) such as scheduling control information, NR PDCCH transmission is defined to be restricted for symbols on which LTE CRS transmission is performed. Accordingly, NR PDCCH can be transmitted only through symbols #1 and #2 or symbol #2 depending on the number of LTE CRS antenna ports among the first three symbols of any DL slot: symbols #0, #1, and #2. Specifically, when the number of LTE CRS antenna ports is 1 or 2, NR PDCCH transmission is possible through symbol #1 and symbol #2, and when the number of LTE CRS antenna ports is 4, NR PDCCH transmission is possible only through symbol #2.

This limitation of OFDM symbols capable of NR PDCCH transmission may cause a shortage of NR PDCCH capacity, and as a solution to this, there is a need for technology to support NR PDCCH transmission even for OFDM symbols on which LTE CRS transmission is performed. This is increasing.

Therefore, this specification proposes a method for supporting NR PDCCH transmission in a symbol where LTE CRS transmission is performed. In particular, when the radio resources allocated for NR PDCCH transmission include LTE CRS, how to set rate matching for the LTE CRS, and RE(s) and LTE in which DM-RS transmission for demodulation of NR PDCCH is performed If overlap occurs between RE(s) where CRS transmission is performed, a method to resolve this is proposed.

Point 1: LTE CRS rate matching configuration

When the base station transmits NR PDCCH and the terminal monitors and receives NR PDCCH, it is defined not to transmit or receive PDCCH payload or PDCCH DM-RS for RE(s) used for LTE CRS transmission. , this can be set by the base station.

To support DSS, any NR base station transmitted LTE CRS rate matching pattern setting information for the NR PDSCH to the terminal in the corresponding cell through RRC signaling (radio resource control signaling). In other words, an RRC IE (Information Element) " RateMatchPatternLTE-CRS " for transmitting LTE CRS rate matching setting information for NR PDSCH has been defined, and the corresponding RRC IE contains information as shown in Tables 5 and 6. defined to include Accordingly, any NR terminal is defined not to expect reception of the NR PDSCH for the RE(s) used for the corresponding LTE CRS transmission when receiving the NR PDSCH. Likewise, it can be defined that rate matching is performed for NR PDCCH reception according to the corresponding “ RateMatchPatternLTE-CRS ”.

RateMatchPatternLTE-CRS information element

--ASN1START
-- TAG-RATEMATCHPATTERNLTE-CRS-START

RateMatchPatternLTE-CRS ::= SEQUENCE {
carrierFreqDL INTEGER (0..16383);
carrierBandwidthDL ENUMERATED {n6, n15, n25, n50, n75, n100, spare2, spare1},
mbsfn-SubframeConfigList EUTRA-MBSFN-SubframeConfigList OPTIONAL, -- Need M
nrofCRS-Ports ENUMERATED {n1, n2, n4},
v-Shift ENUMERATED {n0, n1, n2, n3, n4, n5}
}

LTE-CRS-PatternList-r16 ::= SEQUENCE (SIZE (1..maxLTE-CRS-Patterns-r16)) OF RateMatchPatternLTE-CRS

-- TAG-RATEMATCHPATTERNLTE-CRS-STOP
--ASN1STOP

RateMatchPatternLTE-CRS field descriptions carrierBandwidthDL
BW of the LTE carrier in number of PRBs (see TS 38.214 [19], clause 5.1.4.2). carrierFreqDL
Center of the LTE carrier (see TS 38.214 [19], clause 5.1.4.2). mbsfn-SubframeConfigList
LTE MBSFN subframe configuration (see TS 38.214 [19], clause 5.1.4.2). nrofCRS-Ports
Number of LTE CRS antenna port to rate-match around (see TS 38.214 [19], clause 5.1.4.2). v-Shift
Shifting value v-shift in LTE to rate match around LTE CRS (see TS 38.214 [19], clause 5.1.4.2).

In this specification, as a method for applying LTE CRS rate matching to the corresponding NR PDCCH, LTE CRS rate matching to the NR PDCCH may be set in CORESET units or search space units. In other words, when configuring CORESET for an arbitrary terminal at the NR base station, it can be defined to include indication information for applying NR PDCCH rate matching according to the corresponding " RateMatchPatternLTE-CRS ". Specifically, an information area for indicating whether to apply LTE CRS rate matching according to " RateMatchPatternLTE-CRS " is defined in the RRC IE for setting CORESET for any terminal, and based on this, through the corresponding CORESET. It is possible to determine whether to apply LTE CRS rate matching to the NR PDCCH where transmission occurs. Alternatively, carrierFreqDL, carrierBandwidthDL, mbsfn-SubframeConfigList information, etc. included in the above " RateMatchPatternLTE-CRS " can be directly included in the CORESET setting information and defined so that LTE CRS rate matching for NR PDCCH is performed based on this. Alternatively, when setting a search space for an arbitrary terminal in an NR base station, it can be defined to include indication information for applying NR PDCCH rate matching according to " RateMatchPatternLTE-CRS ". Specifically, an information area for indicating whether to apply CRS rate matching according to the " RateMatchPatternLTE-CRS " setting is defined in the RRC IE for setting a search space for an arbitrary terminal, and based on this, It is possible to determine whether to apply LTE CRS rate matching to the NR PDCCH transmitted through the corresponding search space. Alternatively, the search space setting information can be defined to directly include the carrierFreqDL, carrierBandwidthDL, and mbsfn-SubframeConfigList information included in " RateMatchPatternLTE-CRS " above so that LTE CRS rate matching is performed based on this. You can.

As another method for applying LTE CRS rate matching to the NR PDCCH, it can be defined so that whether or not LTE CRS rate matching to the corresponding NR PDCCH is determined on a per-terminal basis.

As an example of this, any terminal is defined to implicitly determine whether or not to do LTE CRS rate matching for the NR PDCCH according to the UE capability setting information and the " RateMatchPatternLTE-CRS " setting above. can do. Specifically, the base station and the terminal can exchange information about whether LTE CRS rate matching for the NR PDCCH of the corresponding terminal is supported through UE capability configuration information. Based on this, LTE CRS rate matching support for NR PDCCH is determined in any terminal. At this time, if any terminal supports LTE CRS rate matching for NR PDCCH, LTE CRS rate matching for NR PDCCH is determined depending on whether " RateMatchPatternLTE-CRS " is set. In other words, in the case of a terminal for which arbitrary LTE CRS pattern information is set through reception of " RateMatchPatternLTE-CRS ", rate matching for LTE CRS RE(s) is assumed when receiving NR PDCCH according to that information. It can be defined as: That is, if the NR PDCCH transmission for the corresponding terminal includes the RE(s) in which LTE CRS transmission is performed according to the above " RateMatchPatternLTE-CRS ", the corresponding NR PDCCH transmission is the rate for the RE(s) in which LTE CRS transmission is performed. It can be defined so that rate matching occurs.

Alternatively, by defining an additional information area to indicate whether to set rate matching for the NR PDCCH in the “ RateMatchPatternLTE-CRS ”, the base station can perform LTE CRS rate matching for the NR PDCCH through the information area. ) Can be defined to explicitly signal whether to apply. Accordingly, for any terminal that supports LTE CRS rate matching for NR PDCCH, LTE CRS rate matching according to the " RateMatchPatternLTE-CRS " setting for the NR PDCCH for that terminal at the base station. It can be transmitted to the relevant terminal by additionally including explicit setting information on whether to apply it. The terminal can define whether to apply rate matching for LTE CRS when receiving the NR PDCCH according to “ RateMatchPatternLTE-CRS ” set by the base station.

Point 2: PDCCH DM-RS collision handling

CORESET settings for PDCCH transmission for any NR terminal can be set up to 3 symbols on the time axis. Accordingly, in the case of CORESET setting for PDCCH transmission including PDSCH/PUSCH scheduling control information based on arbitrary mapping type A, it can be made up to the first 3 symbols of any NR slot on the time axis.

DM-RS for NR PDCCH transmission on the frequency axis includes 12 subcarriers with subcarrier indices #0 to #11 constituting one PRB, as shown in Tables 5 to 7 below. It is transmitted through three subcarriers with subcarrier indices #1, #5, and #9.

On the other hand, in the case of LTE CRS, when the number of antenna ports is 1 or 2, it is transmitted through the first OFDM symbol, when the number of antenna ports is 4, it is transmitted through the first and second OFDM symbols, and on the frequency axis, when the number of antenna ports is 1 , is transmitted through subcarriers #0 and #6, and when the number of antenna ports is 2 or 4, it is transmitted through subcarriers #0, #3, #6, and #9, respectively. However, in the case of the frequency axis, transmission is performed by shifting on the frequency axis according to the vshift value according to PCID (physical cell ID).

When NR PDCCH and LTE CRS are transmitted through the same symbol within one PRB, if a collision occurs between the NR PDCCH DM-RS and LTE CRS, the number of LTE CRS antenna ports (antenna port) Number) is as shown in Tables 7 to 9 below. Specifically, Tables 7 to 8 show collision cases according to vshift values when the LTE CRS antenna port number is 1, and Table 9 shows the LTE CRS antenna port number. If is 2 or 4, it indicates a collision case according to the vshift value.

Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS 11 11 11 10 10 10 9 NR-DMRS 9 NR-DMRS 9 NR-DMRS 8 8 8 port 0 7 7 port 0 7 6 port 0 6 6 5 NR-DMRS 5 NR-DMRS 5 NR-DMRS 4 4 4 3 3 3 2 2 2 port 0 One NR-DMRS One NR-DMRS port 0 One NR-DMRS 0 port 0 0 0

Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS 11 11 11 port 0 10 10 port 0 10 9 NR-DMRS port 0 9 NR-DMRS 9 NR-DMRS 8 8 8 7 7 7 6 6 6 5 NR-DMRS 5 NR-DMRS 5 NR-DMRS port 0 4 4 port 0 4 3 port 0 3 3 2 2 2 One NR-DMRS One NR-DMRS One NR-DMRS 0 0 0

Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS Subcarrier
index
in a PRB RE(s) for NR PDCCH DM-RS RE(s)
for
LTE CRS 11 11 11 port 1 or 3 10 10 port 1 or 3 10 9 NR-DMRS port 1 or 3 9 NR-DMRS 9 NR-DMRS 8 8 8 port 0 or 2 7 7 port 0 or 2 7 6 port 0 or 2 6 6 5 NR-DMRS 5 NR-DMRS 5 NR-DMRS port 1 or 3 4 4 port 1 or 3 4 3 port 1 or 3 3 3 2 2 2 port 0 or 2 One NR-DMRS One NR-DMRS port 0 or 2 One NR-DMRS 0 port 0 or 2 0 0

As shown in Tables 7 to 9 above, collision between NR PDCCH DM-RS and LTE CRS depending on the number of LTE CRS antenna ports (=1, 2, or 4) during the first 3 symbols of any DL slot. There may be various cases where a collision occurs.

I. First disclosure: NR PDCCH DM-RS shifting scheme in frequency domain

If overlap occurs with the LTE CRS RE(s) for the RE(s) allocated for NR PDCCH DM-RS transmission, the NR PDCCH DM-RS transmitted through the RE where the overlap occurred can be defined to shift in the frequency domain.

At this time, as the first method of frequency shifting for DM-RS, LTE CRS among DM-RS transmitted through subcarriers #1, #5, and #9 of each PRB in a random symbol. Only the RE of the subcarrier where a collision occurred can be defined to shift by 1 in the positive direction in the frequency domain. In other words, if the subcarrier index where overlap between DM-RS and CRS occurs is N, the DM-RS to be transmitted on subcarrier #N is subcarrier #N+1. It can be sent via . Specifically, NR PDCCH DM-RS transmission is performed through subcarriers #1, #5, and #9 in one PRB. At this time, if a collision occurs with LTE CRS transmission on subcarrier #1, only the DM-RS transmitted through subcarrier #1 is shifted and the subcarrier ( It can be defined to be transmitted to subcarrier #2. In this case, the corresponding symbol is transmitted through subcarriers with subcarrier indexes #2, #5, and #9 in each PRB of the NR DM-RS. Even if a collision occurs with LTE CRS on the remaining subcarrier #5 or #9, 1 subcarrier shifting in the positive direction only for DM-RS transmitted through the corresponding subcarrier. (subcarrier shifting). In other words, it is a shifted DM-RS pattern within a certain PRB, and the sets of subcarrier indices where DM-RS transmission occurs in the corresponding PRB are (#2, #5, #, respectively) 9), (#1, #6, #9), (#1, #5, #10).

As a second method of frequency shifting for DM-RS, collision with LTE CRS among DM-RS transmitted through subcarriers #1, #5, and #9 of each PRB in random symbols Only the RE of the subcarrier where a collision occurred can be defined to shift by 1 in the negative direction in the frequency domain. In other words, if the subcarrier index where overlap between DM-RS and CRS occurs is N, DM-RS is transmitted through subcarrier #N-1 with subcarrier index #N-1. It can be defined to be transmitted. Specifically, NR PDCCH DM-RS transmission is performed through subcarriers with subcarrier indexes #1, #5, and #9 in one PRB. At this time, if a collision occurs with LTE CRS transmission in subcarrier index #1, shifting occurs only for the DM-RS transmitted through subcarrier #1. It can be defined to be transmitted on subcarrier #0. In this case, in the corresponding symbol, the NR DM-RS is transmitted through subcarriers with subcarrier indexes #0, #5, and #9 in each PRB. Even if a collision occurs with LTE CRS on the remaining subcarriers #5 or #9, 1 subcarrier shifting in the negative direction only for DM-RS transmitted through the corresponding subcarrier. (subcarrier shifting). In other words, it is a shifted DM-RS pattern within a certain PRB, and the sets of subcarrier indices where DM-RS transmission occurs in the corresponding PRB are (#0, #5, #, respectively) 9), (#1, #4, #9), (#1, #5, #8).

As a third method of frequency shifting for DM-RS, when the LTE CRS antenna port number is 1 and a collision occurs with LTE CRS on any subcarrier, Not only the subcarrier of the DM-RS RE, but also the entire DM-RS RE within the PRB can be defined to shift in the frequency domain. That is, in Tables 5 and 6 above, when the vshift values of LTE CRS are 1, 3, and 5, respectively, collisions occur at subcarriers #1, #5, and #9, respectively. In this case, In the symbol, shift the NR DM-RS in the positive direction to transmit via subcarriers #2, #6, and #10, or shift it in the negative direction to transmit via subcarriers #0, #4, and It can be defined to be transmitted in #8.

To apply frequency shifting (i.e., subcarrier shifting) to the NR PDCCH DM-RS described above, the base station provides the UE with frequency information (e.g. carrierFreqDL information, carrierBandwidthDL information, etc.) at which LTE CRS transmission occurs when setting a random CORESET. ) and LTE CRS antenna port number information (i.e., nrofCRS-Ports information) and vshift information can be newly defined to include. Based on this, any NR terminal obtains information on REs where LTE CRS transmission occurs, and when LTE CRS transmission is expected in any NR PDCCH DM-RS RE(s), the various DM-RS shifting patterns described above are used. One of the DM-RS shifting patterns can be applied. At this time, the shifting pattern to be applied can be defined as one of the methods described above. In other words, the same shifting method can be defined to be applied to all DM-RS and CRS collision cases in Tables 5 to 7 above. Alternatively, a separate shifting method can be defined to be applied for each collision case. For example, in the case where the number of LTE CRS antenna ports is 1 (i.e., the case corresponding to Table 6 in Table 5), the third method described above is applied, and the number of LTE CRS ports is 2 or 4. In this case, it can be defined to apply the first or second method described above. That is, the NR PDCCH DM-RS shifting pattern can be defined and mapped for each collision case.

Alternatively, the base station can define to directly set the corresponding DM-RS shifting pattern information through higher layer signaling. For example, it can be defined to include DM-RS shifting pattern information in addition to the CORESET setting information described above.

II. Second disclosure: NR PDCCH DM-RS shifting scheme in time domain

If a collision occurs between the corresponding NR PDCCH DM-RS transmission and LTE CRS transmission in one or more RE(s) for the RE(s) allocated for NR PDCCH DM-RS transmission in any symbol, NR -PDCCH DM-RS transmission symbols can be defined for shifting. Specifically, collision between NR PDCCH DM-RS and LTE CRS in one symbol or two symbols depending on the duration of CORESET (number of symbols for CORESET) and the number of LTE CRS antenna ports. This can happen. In this case, it can be defined to shift the PDCCH DM-RS transmission symbol of the corresponding CORESET by the number of symbols where collision occurs.

For example, if the CORESET duration is set to 3 (i.e., when PDCCH is transmitted through the first 3 symbols of a random slot) and the number of CRS ports is 2, NR PDCCH DM in the first symbol -Collision may occur between RS and LTE CRS. In this case, the NR PDCCH DM-RS transmitted through the first, second, and third symbols, respectively, can be defined to be shifted by 1 symbol and transmitted through the second, third, and fourth symbols.

However, time domain shifting may be limited within the set CORESET duration. For example, if the CORESET duration is set to 3 and the number of LTE CRS ports is 2, and time shifting is restricted within the CORESET duration, NR PDCCH DM-RS Rather than shifting, it can be defined to transmit the NR PDCCH DM-RS through the second and third symbols, excluding the first symbol where a collision occurs between the NR PDCCH DM-RS and the LTE CRS. That is, in the case of NR PDCCH DM-RS, the existing pattern can be maintained on the existing frequency axis, but transmission can be defined so that transmission occurs only in the remaining symbols excluding the symbols in which LTE CRS transmission is performed.

III. Third disclosure: NR PDCCH DM-RS puncturing scheme

When LTE CRS transmission is performed on a RE(s) allocated for NR PDCCH DM-RS transmission in a random symbol, the NR PDCCH DM-RS can be defined to be punctured in the corresponding RE(s). Within one PRB, NR PDCCH DM-RS is transmitted through subcarriers #1, #5, and #9. However, as shown in Tables 5 to 7, a collision between DM-RS transmission and LTE CRS transmission may occur in one symbol or two symbols depending on the number of LTE CRS ports. At this time, it can be defined that NR PDCCH DM-RS transmission is not performed for REs where LTE CRS transmission is performed, that is, DM-RS transmission is punctured. For example, if a collision occurs with LTE CRS transmission on subcarrier #1, NR PDCCH DM-RS can be defined to be transmitted only through subcarriers #5 and #9.

In this case, as with frequency shifting, which is the first method described above, when setting CORESET, the base station is used to apply frequency shifting (i.e., subcarrier shifting) to the NR PDCCH DM-RS. When setting a random CORESET to the terminal, the frequency information at which LTE CRS transmission occurs (e.g. carrierFreqDL information, carrierBandwidthDL information, etc.), LTE CRS antenna port number information (i.e. nrofCRS-Ports information), and vshift information are updated. It can be defined to include. Based on this, any NR terminal obtains information on REs where LTE CRS transmission occurs, and when LTE CRS transmission is expected in any NR PDCCH DM-RS RE(s), DM-RS transmission from that RE(s) You can do puncturing. Alternatively, a punctured DM-RS pattern can be defined to indicate it directly through higher layer signaling. For example, a punctured DM-RS pattern for subcarrier #1 or a punctured DM-RS pattern for subcarrier #5 and subcarrier #9. Each RS (punctured DM-RS) can be defined to signal information about it directly to the terminal.

Additionally, the base station can directly set/instruct or implicitly set the method to be applied among the first to third methods (frequency domain shifting, time domain shifting, and puncturing). For example, the base station can define the method to be applied among the above methods to signal to the terminal. In other words, cell-specific or UE-specific CORESET configuration information is defined to include the PDCCH candidate configured through the corresponding CORESET and DM-RS transmission configuration information for the PDCCH transmitted through it. can do. Alternatively, the above NR PDCCH DM-RS shifting or puncturing can be implicitly defined to be applied according to the density of the DM-RS. In other words, whether to apply puncturing or shifting depending on the number of symbols in which a collision with the LTE CRS occurs (1 symbol or 2 symbols) and the duration of CORESET. You can define it to decide. Alternatively, the corresponding PDCCH DM-RS transmission method can be defined to be derived depending on the presence or absence of symbols that do not include LTE CRS or the ratio of symbols that include LTE CRS among the entire CORESET duration. In other words, for each collision case, the method to be applied among the frequency domain shifting, time domain shifting, or puncturing methods described above can be defined to be mapped. You can.

Here, the corresponding NR PDCCH DM-RS transmission method setting/instruction information is described from the base station's perspective, and when defined from the terminal's perspective, the NR PDCCH DM-RS reception method setting/instruction information or channel estimation for the NR PDCCH accordingly ( channel estimation) can be defined as a method setting/instruction information area. However, in the case of punctured DM-RS (punctured DM-RS), which is the third disclosed method, setting/instruction information regarding whether to transmit punctured DM-RS (punctured DM-RS) to the terminal is separately defined. This may not be possible, and in this case, the base station punctures the NR PDCCH DM-RS transmission in the RE that overlaps the LTE CRS, or in the case of the terminal, follows the existing NR PDCCH channel estimation method. Alternatively, channel estimation based on punctured DM-RS may be performed.

For example, the time shifting method, which is the second method described above, and the puncturing method, which is the third method, can be applied, and when setting a random CORESET, the base station sends information to the terminal, including the corresponding setting information. It can be defined to transmit, or it can be defined to indicate the corresponding DM-RS transmission method through MAC CE signaling for any CORESET. Alternatively, it may be defined to include setting information for channel estimation of the terminal according to the corresponding DM-RS transmission. That is, according to the method of the second disclosure described above, it includes information for setting to perform channel estimation only for DM-RS REs of symbols that do not overlap with the symbol in which LTE CRS transmission is performed, or Alternatively, according to Scheme 3 of the third disclosure described above, it may include information that configures channel estimation to be performed using existing DM-RS REs in all symbols, including symbols in which all LTE CRS transmissions occur. . Alternatively, depending on whether any CORESET or PDCCH transmission includes symbols for which LTE CRS transmission is not performed according to an implicit method, DM- of symbols not including LTE CRS transmission according to the method of the second disclosure described above It can be defined to determine whether to perform channel estimation based only on RS REs or based on existing NR PDCCH DM-RS REs.

In addition, in the present invention, signaling from the base station to the terminal refers to higher layer signaling, medium access control (MAC) control element (CE) signaling, or Layer 1 (L1) control signaling. It can either explicitly signal to the terminal or include an implicit signaling method. Here, higher layer signaling refers to RRC signaling transmitted through PDSCH, and is UE-specific, cell-specific, or UE-group common. Includes RRC signaling. L1 control signaling is DCI (Downlink Control Information) transmitted through PDCCH, and is UE-specific DCI or UE-group common DCI or cell-specific. ) may include DCI. Implicit signaling may include cases where the setting is determined depending on the setting of other information.

<Summary of embodiments of this specification>

Figure 13 shows a method of operating a terminal according to an embodiment of the present specification.

Referring to FIG. 13, the terminal monitors a new radio technology (NR) PDCCH in one or more orthogonal frequency division multiplexing (OFDM) symbols within a slot (S1301). Here, the slot is used for long term evolution (LTE) cell-specific reference signal (CRS).

Meanwhile, the demodulation reference signal (DM-RS) of the NR PDCCH is received in at least one OFDM symbol in the slot (S1302), and the resource element (RE) used for the DM-RS for decoding the NR PDCCH is LTE ( long term evolution) does not overlap with the RE used in CRS.

Afterwards, the terminal performs channel estimation based on the received DM-RS (S1303).

At least one OFDM symbol for receiving the DM-RS for decoding the NR PDCCH described above may be an OFDM symbol that does not include the LTE CRS. And, DM-RS puncturing can be applied to RE used in LTE CRS.

Meanwhile, although not shown in FIG. 13, before the UE performs NR PDCCH monitoring on one or more OFDM symbols in a slot, LTE CRS configuration information may be received from the base station through radio resource control (RRC) signaling. You can. Here, the LTE CRS configuration information may be rate matching pattern configuration information of the LTE CRS for the NR PDCCH.

Figure 14 shows a method of operating a base station according to an embodiment of the present specification.

Referring to FIG. 14, the base station configures one or more orthogonal frequency division multiplexing (OFDM) symbols in a slot for new radio technology (NR) physical downlink control channel (PDCCH) transmission (S1401). Here, the slot is used for long term evolution (LTE) cell-specific reference signal (CRS).

Then, a demodulation reference signal (DM-RS) for decoding the NR PDCCH is allocated to at least one OFDM symbol in the slot (S1402).

Afterwards, the NR PDCCH and the DM-RS for decoding the NR PDCCH are transmitted to the terminal (S1403). The RE (resource element) used for the DM-RS for decoding the NR PDCCH does not overlap with the RE used for the LTE CRS. No.

At least one OFDM symbol allocating a DM-RS for decoding the NR PDCCH described above may be an OFDM symbol that does not include an LTE CRS. And, DM-RS puncturing can be applied to RE used in LTE CRS.

Meanwhile, although not shown in FIG. 14, before the base station transmits the NR PDCCH and the DM-RS for decoding the NR PDCCH, LTE CRS configuration information can be transmitted to the terminal through radio resource control (RRC) signaling. there is. Here, the LTE CRS configuration information may be rate matching pattern configuration information of the LTE CRS for the NR PDCCH.

IV. Device general to which the disclosure of this specification may be applied

The disclosures herein described so far may be implemented through various means. For example, the disclosures herein may be implemented by hardware, firmware, software, or a combination thereof. Specifically, the description will be made with reference to the drawings.

Figure 15 shows a device according to one embodiment.

Referring to FIG. 15, a wireless communication system may include a first device 100a and a second device 100b.

The first device 100a may be a base station, a network node, a transmitting terminal, a receiving terminal, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, or a drone (Unmanned Aerial Vehicle, UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device, pin It may be a tech device (or financial device), security device, climate/environment device, device related to 5G service, or other device related to the 4th Industrial Revolution field.

The second device 100b is a base station, a network node, a transmitting terminal, a receiving terminal, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, and a drone (Unmanned Aerial Vehicle, UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device, pin It may be a tech device (or financial device), security device, climate/environment device, device related to 5G service, or other device related to the 4th Industrial Revolution field.

The first device 100a may include at least one processor such as the processor 1020a, at least one memory such as the memory 1010a, and at least one transceiver such as the transceiver 1031a. The processor 1020a may perform the functions, procedures, and/or methods described above. The processor 1020a may perform one or more protocols. For example, the processor 1020a may perform one or more layers of a wireless interface protocol. The memory 1010a is connected to the processor 1020a and can store various types of information and/or commands. The transceiver 1031a is connected to the processor 1020a and can be controlled to transmit and receive wireless signals.

The second device 100b may include at least one processor such as the processor 1020b, at least one memory device such as the memory 1010b, and at least one transceiver such as the transceiver 1031b. The processor 1020b may perform the functions, procedures, and/or methods described above. The processor 1020b may implement one or more protocols. For example, the processor 1020b may implement one or more layers of a wireless interface protocol. The memory 1010b is connected to the processor 1020b and can store various types of information and/or commands. The transceiver 1031b is connected to the processor 1020b and can be controlled to transmit and receive wireless signals.

The memory 1010a and/or the memory 1010b may be connected to each other inside or outside the processor 1020a and/or the processor 1020b, and may be connected to other processors through various technologies such as wired or wireless connection. It may also be connected to .

The first device 100a and/or the second device 100b may have one or more antennas. For example, antenna 1036a and/or antenna 1036b may be configured to transmit and receive wireless signals.

Figure 16 is a block diagram showing the configuration of a terminal according to an embodiment.

In particular, Figure 16 is a diagram illustrating the device of Figure 15 in more detail.

The device includes a memory 1010, a processor 1020, a transceiver 1031, a power management module 1091, a battery 1092, a display 1041, an input unit 1053, a speaker 1042, and a microphone 1052. Includes a subscriber identification module (SIM) card and one or more antennas.

Processor 1020 may be configured to implement the suggested functions, procedures and/or methods described herein. Layers of a radio interface protocol may be implemented in the processor 1020. Processor 1020 may include an application-specific integrated circuit (ASIC), other chipset, logic circuit, and/or data processing device. The processor 1020 may be an application processor (AP). The processor 1020 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). Examples of processors 1020 include SNAPDRAGONTM series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, A series processors manufactured by Apple®, HELIOTM series processors manufactured by MediaTek®, INTEL® It may be an ATOM™ series processor manufactured by, a KIRINT™ series processor manufactured by HiSilicon®, or a corresponding next-generation processor.

The power management module 1091 manages power for the processor 1020 and/or the transceiver 1031. Battery 1092 supplies power to power management module 1091. The display 1041 outputs the results processed by the processor 1020. Input unit 1053 receives input to be used by processor 1020. The input unit 1053 may be displayed on the display 1041. A SIM card is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and its associated keys, which are used to identify and authenticate subscribers in mobile phone devices such as mobile phones and computers. You can also store contact information on many SIM cards.

The memory 1010 is operably coupled to the processor 1020 and stores various information for operating the processor 610. Memory 1010 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. When an embodiment is implemented as software, the techniques described herein may be implemented as modules (eg, procedures, functions, etc.) that perform the functions described herein. Modules may be stored in memory 1010 and executed by processor 1020. The memory 1010 may be implemented inside the processor 1020. Alternatively, the memory 1010 may be implemented external to the processor 1020 and may be communicatively connected to the processor 1020 through various means known in the art.

The transceiver 1031 is operably coupled to the processor 1020 and transmits and/or receives wireless signals. The transceiver unit 1031 includes a transmitter and a receiver. The transceiver 1031 may include a baseband circuit for processing radio frequency signals. The transceiver controls one or more antennas to transmit and/or receive wireless signals. The processor 1020 transmits command information to the transceiver 1031 to initiate communication, for example, to transmit a wireless signal constituting voice communication data. The antenna functions to transmit and receive wireless signals. When receiving a wireless signal, the transceiver 1031 may transfer the signal and convert the signal to baseband for processing by the processor 1020. The processed signal may be converted into audible or readable information output through the speaker 1042.

The speaker 1042 outputs sound-related results processed by the processor 1020. Microphone 1052 receives sound-related input to be used by processor 1020.

The user inputs command information such as a phone number, for example, by pressing (or touching) a button on the input unit 1053 or by voice activation using the microphone 1052. The processor 1020 receives this command information and processes it to perform appropriate functions, such as calling a phone number. Operational data can be extracted from the SIM card or memory 1010. Additionally, the processor 1020 may display command information or driving information on the display 1041 for the user's recognition and convenience.

Figure 17 shows a configuration block diagram of a processor on which the disclosure of the present specification is implemented.

As can be seen with reference to FIG. 17, the processor 1020 on which the disclosure of the present disclosure is implemented includes a plurality of circuitry to implement the proposed functions, procedures and/or methods described herein. can do. For example, the processor 1020 may include a first circuit 1020-1, a second circuit 1020-2, and a third circuit 1020-3. Additionally, although not shown, the processor 1020 may include more circuits. Each circuit may include a plurality of transistors.

The processor 1020 may be called an application-specific integrated circuit (ASIC) or an application processor (AP), and includes at least one of a digital signal processor (DSP), a central processing unit (CPU), and a graphics processing unit (GPU). can do.

FIG. 18 is a block diagram showing in detail the transceiver of the first device shown in FIG. 15 or the transceiver unit of the device shown in FIG. 16.

Referring to FIG. 18, the transceiver 1031 includes a transmitter 1031-1 and a receiver 1031-2. The transmitter (1031-1) includes a Discrete Fourier Transform (DFT) unit (1031-11), a subcarrier mapper (1031-12), an IFFT unit (1031-13), a CP insertion unit (1031-14), and a wireless transmitter (1031). -15). The transmitter 1031-1 may further include a modulator. In addition, it may further include, for example, a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown), and a layer permutator (not shown), This may be placed prior to the DFT unit 1031-11. That is, in order to prevent an increase in the peak-to-average power ratio (PAPR), the transmitter 1031-1 first passes information through the DFT 1031-11 before mapping the signal to the subcarrier. The signal spread (or precoded in the same sense) by the DFT unit 1031-11 is subcarrier mapped through the subcarrier mapper 1031-12, and then again in the IFFT (Inverse Fast Fourier Transform) unit 1031-12. 13) to create a signal on the time axis.

The DFT unit 1031-11 performs DFT on the input symbols and outputs complex-valued symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit 1031-11 may be called a transform precoder. The subcarrier mapper 1031-12 maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1031-12 may be called a resource element mapper. The IFFT unit 1031-13 performs IFFT on the input symbols and outputs a baseband signal for data that is a time domain signal. The CP insertion unit 1031-14 copies a part of the latter part of the basic band signal for data and inserts it into the front part of the basic band signal for data. Through CP insertion, ISI (Inter-Symbol Interference) and ICI (Inter-Carrier Interference) are prevented, and orthogonality can be maintained even in multi-path channels.

On the other hand, the receiver 1031-2 includes a wireless reception unit 1031-21, a CP removal unit 1031-22, an FFT unit 1031-23, and an equalization unit 1031-24. The wireless receiving unit 1031-21, CP removing unit 1031-22, and FFT unit 1031-23 of the receiver 1031-2 are the wireless transmitting unit 1031-15 in the transmitting end 1031-1, It performs the reverse function of the CP insertion unit (1031-14) and the IFF unit (1031-13). The receiver 1031-2 may further include a demodulator.

In the above, preferred embodiments have been described by way of example, but the disclosure of the present specification is not limited to these specific embodiments, and may be modified, changed, or modified in various forms within the scope described in the spirit and claims of the present specification. It can be improved.

In the example system described above, the methods are described on the basis of a flow chart as a series of steps or blocks, but the order of steps described is not limited, and some steps may occur simultaneously or in a different order than other steps as described above. there is. Additionally, those skilled in the art will understand that the steps shown in the flowchart are not exclusive and that other steps may be included or one or more steps in the flowchart may be deleted without affecting the scope of rights.

The claims set forth herein may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Additionally, the technical features of the method claims of this specification and the technical features of the device claims may be combined to implement a device, and the technical features of the method claims of this specification and technical features of the device claims may be combined to implement a method.

Claims (15)

In a method for a terminal to monitor a new radio technology (NR) PDCCH (physical downlink control channel) in a wireless communication system,
Monitoring the PDCCH at one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols within a slot, wherein the slot is used for a long term evolution (LTE) cell-specific reference signal (CRS); and
Receiving a demodulation reference signal (DM-RS) for decoding the PDCCH in at least one OFDM symbol in the slot,
A method wherein the RE (resource element) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS. According to paragraph 1,
When symbols including the LTE CRS and symbols not including the LTE CRS are mixed in the plurality of OFDM symbols for monitoring the PDCCH, a DM-RS for decoding the PDCCH is provided that does not include the LTE CRS. A method for receiving only the at least one OFDM symbol. According to paragraph 1,
A method characterized in that DM-RS puncturing is applied to the RE used for the LTE CRS. According to paragraph 1,
The method further comprising receiving configuration information of the LTE CRS. According to paragraph 4,
The method wherein the LTE CRS configuration information is rate matching pattern configuration information of the LTE CRS for the PDCCH. According to paragraph 4,
The configuration information of the LTE CRS is received through radio resource control (RRC) signaling. In a method for a base station to transmit a new radio technology (NR) PDCCH (physical downlink control channel) in a wireless communication system,
Configuring one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a slot for the PDCCH transmission, wherein the slot is used for a long term evolution (LTE) cell-specific reference signal (CRS);
Allocating a demodulation reference signal (DM-RS) for decoding the PDCCH to at least one OFDM symbol in the slot; and
Including transmitting the PDCCH and a DM-RS for decoding the PDCCH,
A method wherein the RE (resource element) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS. In clause 7,
When symbols including the LTE CRS and symbols not including the LTE CRS are mixed in the plurality of OFDM symbols for transmitting the PDCCH, a DM-RS for decoding the PDCCH is provided that does not include the LTE CRS. A method of transmitting only the at least one symbol. In clause 7,
A method characterized in that DM-RS puncturing is applied to the RE used for the LTE CRS. In clause 7,
A method further comprising transmitting configuration information of the LTE CRS. According to clause 10,
The method wherein the LTE CRS configuration information is rate matching pattern configuration information of the LTE CRS for the PDCCH. According to clause 10,
The LTE CRS configuration information is transmitted through radio resource control (RRC) signaling. As a communication device in a wireless communication system,
at least one processor; and
At least one memory storing instructions, operably electrically connectable with the at least one processor, and based on the instructions being executed by the at least one processor, perform The behavior is:
Monitoring a new radio technology (NR) physical downlink control channel (PDCCH) in one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols within a slot, wherein the slot is a long term evolution (LTE) cell-specific reference (CRS) signal), and
Receiving a demodulation reference signal (DM-RS) for decoding the PDCCH in at least one OFDM symbol in the slot,
A communication device in which the RE (resource element) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS. As a base station in a wireless communication system,
at least one processor; and
At least one memory for storing instructions, operably electrically connectable with the at least one processor, and based on the instructions being executed by the at least one processor, perform The behavior is:
Configuring one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols in a slot for new radio technology (NR) physical downlink control channel (PDCCH) transmission, wherein the slot is a long term evolution (LTE) CRS (cell- It is used for specific reference signal,
Allocating a demodulation reference signal (DM-RS) for decoding the PDCCH to at least one OFDM symbol in the slot, and
Including transmitting the PDCCH and a DM-RS for decoding the PDCCH,
A base station wherein the RE (resource element) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS. A computer-readable storage medium for recording instructions, comprising:
The instructions, when executed by one or more processors, cause the one or more processors to:
A new radio technology (NR) physical downlink control channel (PDCCH) is monitored in one or a plurality of orthogonal frequency division multiplexing (OFDM) symbols within a slot, where the slot is a long term evolution (LTE) cell-specific reference (CRS). signal), and
Receive a demodulation reference signal (DM-RS) for decoding the PDCCH in at least one OFDM symbol in the slot,
A storage medium in which the RE (resource element) used in the DM-RS for decoding the PDCCH does not overlap with the RE used in the LTE CRS.