WO2022149267A1 - Radio base station and terminal - Google Patents

Abstract

This radio base station transmits a demodulation reference signal and sets the configuration of the demodulation reference signal. The radio base station sets the arrangement of the demodulation reference signal in a frequency resource to a first density or a second density different from the first density.

Description

Wireless base stations and terminals

The present disclosure relates to radio base stations and terminals that transmit or receive demodulation reference signals.

The 3rd Generation Partnership Project (3GPP) specifies the 5th generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and next-generation specifications called Beyond 5G, 5G Evolution or 6G. We are also proceeding with the conversion.

For example, in 3GPP Release-17, it has been agreed to consider coverage enhancement (CE: Coverage Enhancement) in NR (Non-Patent Document 1).

Coverage performance affects the estimation accuracy of the demodulation reference signal (DMRS) used for channel estimation of PDSCH (Physical Downlink Shared Channel) / PUSCH (Physical Uplink Shared Channel).

The existing DMRS supports Type 1 (up to 8 ports can be set) and Type 2 (up to 12 ports can be set) configurations, but from the viewpoint of improving the performance of coverage expansion, the estimation accuracy of DMRS has been improved. There seems to be room.

Therefore, the following disclosure is made in view of such a situation, and an object thereof is to provide a radio base station and a terminal capable of improving the estimation accuracy of the demodulation reference signal (DMRS).

One aspect of the present disclosure includes a transmission unit (control signal / reference signal processing unit 140) for transmitting a demodulation reference signal and a control unit (control unit 170) for setting the configuration of the demodulation reference signal. The control unit is a radio base station (gNB100) that sets the arrangement of the demodulation reference signal in the frequency resource to the first density or a second density different from the first density.

In one aspect of the present disclosure, the arrangement of the transmission unit (control signal / reference signal processing unit 140) for transmitting the demodulation reference signal and the (control unit 170) demodulation reference signal in the frequency resource is the first density, or the above. It is a terminal (UE200) provided with a control unit for setting a second density different from the first density.

FIG. 1 is an overall schematic configuration diagram of the wireless communication system 10. FIG. 2 is a diagram showing a configuration example of a wireless frame, a subframe, and a slot used in the wireless communication system 10. FIG. 3 is a functional block configuration diagram of gNB100 and UE200. FIG. 4 is a diagram showing an example of the basic configuration of DMRS. FIG. 5 is a diagram showing a schematic communication sequence regarding transmission / reception of DMRS. FIG. 6 is a diagram showing an example of arrangement of Type 1 and Type 2 DMRS on the RE. FIG. 7 is a diagram showing a configuration example of DMRS having different densities. FIG. 8 is a diagram showing examples of high density and low density DMRS types. FIG. 9 is a diagram showing an example of High DM-RS Density Configuration type. FIG. 10 is a diagram showing an example of Low DM-RS Density Configuration type. FIG. 11 is a diagram showing an example of the hardware configuration of gNB100 and UE200.

Hereinafter, embodiments will be described based on the drawings. The same functions and configurations are designated by the same or similar reference numerals, and the description thereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Wireless Communication System FIG. 1 is an overall schematic configuration diagram of the wireless communication system 10 according to the present embodiment. The wireless communication system 10 is a wireless communication system according to 5G New Radio (NR), and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN20, and a terminal 200 (hereinafter, UE200).

The wireless communication system 10 may be a wireless communication system according to a method called Beyond 5G, 5G Evolution or 6G.

NG-RAN20 includes a wireless base station 100 (hereinafter, gNB100). The specific configuration of the wireless communication system 10 including the number of gNBs and UEs is not limited to the example shown in FIG.

NG-RAN20 actually includes multiple NG-RANNodes, specifically gNB (or ng-eNB), and is connected to a core network (5GC, not shown) according to 5G. In addition, NG-RAN20 and 5GC may be simply expressed as "network".

GNB100 is a wireless base station that complies with NR, and executes wireless communication according to UE200 and NR. gNB100 and UE200 are Massive MIMO that generates a beam with higher directivity by controlling radio signals transmitted from multiple antenna elements, carrier aggregation (CA) that uses multiple component carriers (CC) in a bundle, and It can also support dual connectivity (DC) that communicates simultaneously between the UE and multiple NG-RAN Nodes.

Wireless communication system 10 corresponds to FR1 and FR2. The frequency bands of each FR (Frequency Range) are as follows.

・ FR1: 410 MHz to 7.125 GHz
・ FR2: 24.25 GHz to 52.6 GHz
In FR1, Sub-Carrier Spacing (SCS) of 15, 30 or 60 kHz is used, and a bandwidth (BW) of 5 to 100 MHz may be used. FR2 has a higher frequency than FR1, and SCS of 60 or 120 kHz (240 kHz may be included) is used, and a bandwidth (BW) of 50 to 400 MHz may be used.

Further, the wireless communication system 10 may support a higher frequency band than the frequency band of FR2. Specifically, the wireless communication system 10 can support a frequency band exceeding 52.6 GHz and up to 114.25 GHz.

Further, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) / Discrete Fourier Transform-Spread (DFT-S-OFDM) having a larger Sub-Carrier Spacing (SCS) may be applied. Further, DFT-S-OFDM may be applied not only to the uplink (UL) but also to the downlink (DL).

FIG. 2 shows a configuration example of a wireless frame, a subframe, and a slot used in the wireless communication system 10.

As shown in FIG. 2, one slot is composed of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). The number of symbols constituting one slot does not necessarily have to be 14 symbols (for example, 28, 56 symbols). Further, the number of slots per subframe may differ depending on the SCS. Further, the SCS may be wider than 240 kHz (for example, 480 kHz, 960 kHz as shown in FIG. 2).

The time direction (t) shown in FIG. 2 may be referred to as a time domain, a symbol period, a symbol time, or the like. Further, the frequency direction may be referred to as a frequency domain, a resource block, a subcarrier, a BWP (Bandwidth part), or the like.

The wireless communication system 10 can support coverage enhancement (CE: Coverage Enhancement) that expands the coverage of cells (or physical channels) formed by gNB100. Coverage extension may provide a mechanism for increasing the reception success rate of various physical channels.

For example, the wireless communication system 10 (gNB100) can support repeated transmission of PDSCH (Physical Downlink Shared Channel).

Further, in the wireless communication system 10, the demodulation reference signal (DMRS) configuration type used for channel estimation of PDSCH / PUSCH (Physical Uplink Shared Channel) or wireless resources, particularly frequency resources (may be in the frequency direction). The arrangement of DMRS (which may be read as density) can be changed according to the frequency band to be used (may be FR), whether coverage extension is applied, and the like.

(2) Functional block configuration of the wireless communication system Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configuration of gNB100 will be described. FIG. 3 is a functional block configuration diagram of gNB100 and UE200.

As shown in FIG. 3, the gNB 100 includes a radio signal transmission / reception unit 110, an amplifier unit 120, a modulation / demodulation unit 130, a control signal / reference signal processing unit 140, a coding / decoding unit 150, a data transmission / reception unit 160, and a control unit 170. ..

It should be noted that FIG. 3 shows only the main functional blocks related to the description of the embodiment, and that the gNB100 (UE200) has other functional blocks (for example, a power supply unit). Further, FIG. 3 shows the functional block configuration of the gNB 100, and refer to FIG. 11 for the hardware configuration.

The radio signal transmission / reception unit 110 transmits / receives a radio signal according to NR. The radio signal transmission / reception unit 110 uses Massive MIMO that generates a beam with higher directivity by controlling radio frequency (RF) signals transmitted from a plurality of antenna elements, and a carrier that bundles and uses a plurality of component carriers (CC). It can support aggregation (CA) and dual connectivity (DC) that communicates between the UE and each of the two NG-RAN Nodes at the same time.

The amplifier unit 120 is composed of PA (Power Amplifier) / LNA (Low Noise Amplifier) and the like. The amplifier unit 120 amplifies the signal output from the modulation / demodulation unit 130 to a predetermined power level. Further, the amplifier unit 120 amplifies the RF signal output from the radio signal transmission / reception unit 110.

The modulation / demodulation unit 130 executes data modulation / demodulation, transmission power setting, resource block allocation, etc. for each specific communication destination (UE200).

The control signal / reference signal processing unit 140 executes processing related to various control signals transmitted / received by the gNB 100. Specifically, the control signal / reference signal processing unit 140 receives various control signals transmitted from the UE 200 via the control channel, for example, control signals of the radio resource control layer (RRC). Further, the control signal / reference signal processing unit 140 transmits various control signals to the UE 200 via the control channel.

Further, the control signal / reference signal processing unit 140 can execute processing using a reference signal (RS) such as DMRS and Phase Tracking Reference Signal (PTRS).

DMRS is a reference signal (pilot signal) known between the base station and the terminal of each terminal for estimating the fading channel used for data demodulation. The PTRS is a terminal-specific reference signal for the purpose of estimating phase noise, which is a problem in high frequency bands.

In addition to DMRS and PTRS, the reference signal may include ChannelStateInformation-ReferenceSignal (CSI-RS), SoundingReferenceSignal (SRS), PositioningReferenceSignal (PRS) for position information, and the like. ..

Channels include control channels and data channels. The control channel includes PDCCH (Physical Downlink Control Channel), PUCCH (Physical Uplink Control Channel), PRACH (Physical Random Access Channel), PBCH (Physical Broadcast Channel) and the like.

The data channels include PDSCH (Physical Downlink Shared Channel) and PUSCH (Physical Uplink Shared Channel). The signal may include a channel and a reference signal.

As described above, the control signal / reference signal processing unit 140 can transmit DMRS. In the present embodiment, the control signal / reference signal processing unit 140 constitutes a transmission unit.

Specifically, the control signal / reference signal processing unit 140 can transmit DMRS used for PDSCH channel estimation toward UE200. The DMRS used for PDSCH (or PUSCH) channel estimation will be described below.

The coding / decoding unit 150 executes data division / concatenation and channel coding / decoding for each specific communication destination (UE200).

Specifically, the coding / decoding unit 150 divides the data output from the data transmission / reception unit 160 into a predetermined size, and executes channel coding for the divided data. Further, the coding / decoding unit 150 decodes the data output from the modulation / demodulation unit 130 and concatenates the decoded data.

The data transmission / reception unit 160 executes transmission / reception of Protocol Data Unit (PDU) and Service Data Unit (SDU). Specifically, the data transmission / reception unit 160 is a PDU / SDU in a plurality of layers (medium access control layer (MAC), radio link control layer (RLC), packet data convergence protocol layer (PDCP), etc.). Assemble / disassemble the.

The control unit 170 controls each functional block constituting the gNB 100. In particular, in the present embodiment, the control unit 170 can set the configuration of the DMRS. Specifically, the control unit 170 can control the allocation of DMRS to radio resources. Radio resources may include frequency and time resources. Further, the radio resource may include a spatial resource (which may be referred to as a spatial direction).

In particular, in the present embodiment, the control unit 170 can change the density of DMRS in the frequency direction. The density of DMRS in the frequency direction is interpreted as the amount of DMRS allocated (arranged) in the reference unit (resource block (RB), subcarrier, ResourceElement (RE) or RE group (REG), etc.) in the frequency direction. May be done.

The control unit 170 may set the DMRS arrangement in the frequency resource to the first density or a second density different from the first density. The first density may be, for example, low density, and the second density may be high density, which is higher than the first density. The first density and the second density are names for convenience, and the second density may be low density and the first density may be high density.

More specifically, the control unit 170 may set the type of DMRS having the first density or the type of DMRS having the second density. As will be described later, 3GPP defines DMRS of Type 1 and Type 2, but DMRS having different densities in the frequency direction described above may be referred to as Type 3 and 4.

Alternatively, the control unit 170 may set the density of DMRS in the frequency direction to the first density or the second density by using a parameter that changes the density of DMRS. Specifically, the control unit 170 may change only the density of DMRS.

For example, the control unit 170 does not specifically set a new type of DMRS as described above, and uses a parameter (which may be called a scaling factor) that can change the density of DMRS in the frequency direction. The density may be varied. That is, the density of DMRS according to the existing Type 1 or Type 2 may be changed by applying the scaling factor to the existing Type 1 or Type 2 DMRS. A parameter or the like that directly specifies the density of DMRS may be used instead of the scaling factor.

The new type of DMRS described above, or the change in DMRS density using a scaling factor, may be applied to at least one of the downlink (DL) and uplink (UL). That is, the DMRS used for at least one of the PDSCH or PUSCH channel estimates may be subject to the new types of DMRS described above, or DMRS density changes using scaling factors. Examples of new types of DMRS and scaling factors will be described later.

In addition, the above-mentioned DMRS transmission / reception and control functions may be provided in the UE200. For example, the UE 200 may include a control signal / reference signal processing unit 140 (transmission unit) that transmits DMRS used for channel estimation of PUSCH, and a control unit 170 that sets the configuration of DMRS.

Like the gNB100, the control unit 170 of the UE200 may set the DMRS arrangement in the frequency resource to the first density or the second density different from the first density.

Further, the control signal / reference signal processing unit 140 of the UE 200 may transmit DMRS, specifically, UE 200 capability information (UE Capability Information) regarding the type and / or density of the DMRS.

(3) Operation of wireless communication system Next, the operation of the wireless communication system 10 will be described. Specifically, the operation related to the setting of DMRS used for channel estimation of PDSCH / PUSCH will be described.

(3.1) Basic configuration of DMRS Figure 4 shows an example of the basic configuration of DMRS. Specifically, FIG. 4 shows a configuration example of Type 1 and Type 2 of DMRS.

As mentioned above, DMRS is used for PDSCH / PUSCH channel estimation. The coverage performance affects the estimation accuracy of DMRS.

As shown in FIG. 4, the DMRS may have a plurality of types. Specifically, DMRS has Type 1 and Type 2. Type 1 and Type 2 differ in the maximum number of mapping and orthogonal reference signals in the frequency domain. Type 1 can be set up to 8 ports (2 FD-OCC (Orthogonal Cover Code) × 2 Combs × 2 TD-OCC), and Type 2 can be set up to 12 ports (2 FD-OCC × 3 frequency offsets × 2 TD). -OCC) can be set.

Note that Type 1 and Type 2 DMRS may support single-symbol DMRS or double-symbol.

Type 1 and Type 2 are so-called front load DMRSs in which the DMRS sequence is placed on the front symbol in the slot. In Type 1 and Type 2, the sequence is multiplexed in the spatial direction, specifically, using a plurality of ports. The port may mean a gNB port, specifically, an antenna port.

(3.2) Schematic communication sequence FIG. 5 shows a schematic communication sequence relating to transmission / reception of DMRS. As shown in FIG. 5, the UE 200 may transmit UE Capability Information indicating the type or density of DMRS that can be supported to the network.

The network may set the type or density of DMRS to be applied based on the received UE Capability Information, and notify the UE 200 of the setting contents. Specifically, the network may notify the UE 200 of the setting contents by signaling of downlink control information (DCI: Downlink Control Information) or an upper layer (RRC or the like).

The network (gNB100) and UE200 transmit DMRS used for PDSCH / PUSCH channel estimation. Specifically, gNB100 transmits DMRS used for PDSCH channel estimation, and UE200 transmits DMRS used for PUSCH channel estimation.

(3.3) Additional configuration of DMRS Next, the configuration of DMRS for the purpose of expanding the coverage of PDSCH / PUSCH will be described. The accuracy of DMRS estimation depends on the length of the DMRS sequence length and the received power of DMRS. The transmission power of DMRS has the following relationship.

・ When data symbol and DMRS symbol are frequency division multiplexing (FDM): Same power as Data symbol ・ When Data symbol and DMRS symbol are not FDM: Power boosting
The value of Power boosting depends on the number of REs where DMRS is located, as shown in the following formula.

FIG. 6 shows an example of placement of Type 1 and Type 2 DMRS on the RE. The DMRS series length may be expressed as follows. In addition, DMRS may be expressed as DM-RS.

・ (Number of RBs to which resources are allocated) × (Number of REs to which DMRS is placed in 1 RB)
The number of REs in 1RB of DMRS1 port depends on DMRS configuration type. Specifically, as shown in FIG. 6, in the case of DMRS configuration type 1, DMRS is arranged in 6RE in 1RB. In the case of DMRS configuration type 2, DMRS is placed in 4RE in 1RB.

In other words, the estimation accuracy of DMRS can be improved by changing the DMRS Density and changing the transmission power or series length of DMRS.

In addition, the estimation accuracy of DMRS depends on the density of DMRS (Density) of the DMRS series length and the received power of DMRS, which determine the estimation accuracy.

The estimation accuracy of DMRS can be improved by changing the density of DMRS and changing the transmission power or series length of DMRS.

FIG. 7 shows a configuration example of DMRS having different densities. Specifically, FIG. 7 shows a configuration example of high-density (High DM-RS) and low-density (Low DM-RS) DMRS.

High DMRS Density can improve the estimation accuracy of DMRS because it can respond to the channel change in the frequency direction in the RB by securing the DMRS series length.

In addition, Low DMRS Density is expected to improve the estimation accuracy of DMRS by improving the transmission power.

(3.4) Operation example Next, an operation example relating to the DMRS setting to which the above-mentioned new DMRS type or density is applied will be described.

Specifically, operation examples 1 to 5 will be described.

-(Operation example 1): High DMRS density / DMRS configuration type
-(Operation example 2): Low DMRS Density / DMRS configuration type
・ DMRS configuration type of comb 4
・ DMRS configuration type of comb 6
-Support for low PAPR (Peak-to-Average Power Ratio) sequence with short sequence length- (Operation example 3): Notification of DMRS configuration type- (Operation example 4): Change only DMRS Density- (Operation example 5): UE Notification of capability (3.4.0) Outline of operation examples 1 and 2 As described above, a plurality of DMRS types having different DMRS densities may be set. Specifically, high density and low density DMRS types may be set.

FIG. 8 shows examples of high density and low density DMRS types. As shown in FIG. 8, for example, the DMRS configuration type of High DMRS density may be DMRS configuration type 3, and the DMRS configuration type of Low DMRS density may be DMRS configuration type 4.

High DMRS Density may have a higher DMRS Density than Configuration type 1. For example, as shown on the left side of FIG. 8, DMRS RE may be arranged by 1 comb.

In the comb structure, DMRS is transmitted for each Nth subcarrier, and N can take a value of 2, for example (comb2 structure).

Low DMRS Density may have a lower DMRS Density than Configuration type 2. For example, as shown on the right side of FIG. 8, DMRS RE may be arranged by 4 combs or 6 combs.

(3.4.1) Operation example 1
The number of DMRS ports is determined by (number of FD-OCCs) × (number of combs) × (number of TD-OCCs), but the number of FD-OCCs may be determined in consideration of the following points.

• Channel reciprocity in the case of Time Division Duplex (TDD) or Frequency Division Duplex (FDD)
・ If the SCS is large, the number of REs in the channel coherent bandwidth will be small, so the optimum DMRS Density may change. ・ Frequency band (band): Channel characteristics at frequency ・ FR1 or FR2: Channel characteristics at frequency 9 shows an example of High DM-RS Density Configuration type. The left side of Fig. 9 shows Configuration type 1, and the right side shows an example of High DM-RS Density Configuration type based on Configuration type 1 (2 FD-OCC x 1 Combs x 2 TD-OCC = 4 ports). show.

Specifically, High DM-RS Density Configuration type is an example of continuous resource mapping of DM-RS Configuration type 1 in the frequency direction.

The DMRS position of the High DM-RS Density Configuration type may be the same as the existing placement method, or is determined according to TDD, FDD, SCS, frequency band (band), and frequency range (FR1, FR2). May be good.

(3.4.2) Operation example 2
In the case of Low DMRS Density configuration type, the number of DMRS ports may be determined in consideration of the same viewpoint as in Operation Example 1.

FIG. 10 shows an example of Low DM-RS Density Configuration type. Specifically, FIG. 10 shows a mapping example of 4 comb and 6 comb Low DM-RS configuration type.

The DMRS position (arrangement) of the High DM-RS Density Configuration type may be the same as the existing arrangement method as in the operation example 1, TDD, FDD, SCS, frequency band (band), frequency range (FR1, FR2). ) May be decided according to.

Also, a Low PAPR sequence with a short sequence length may be supported. When PUSCH's transform precoding is used, the DMRS base sequence is specified by the 3GPP specification and is generated based on the Low PAPR sequence.

Since the 3GPP specification only specifies a Low PAPR sequence with a sequence length of 6 at the shortest, use the DMRS configuration type of Low DMRS Density (comb 4, comb 6) depending on the number of physical resource blocks (PRB). I can't.

Therefore, a Low PAPR sequence with a sequence length of 3 or 2 may be supported so that the Low DM-RS Density Configuration type can be supported.

(3.4.3) Operation example 3
The use of the DMRS configuration type (Type 3, 4) described above may be notified to the UE 200 from the network (gNB100) by any of the following methods.

-Notification by signaling in the upper layer For example, the dmrs-Type of the DMRS-DownlinkConfig information element or DMRS-UplinkConfig information element, which is the information element of the RRC layer, may be changed and ENUMERATED {type2, type3, type4} may be added. ..

-Notification by DCI When notifying UE200 of PDSCH / PUSCH resources, DMRS configuration type may be specified by DCI. In this case, a plurality of DMRS configuration types may be set in the upper layer, and any one of the plurality of DMRS configuration types set by the upper layer may be specified by DCI.

(3.4.4) Operation example 4
As described above, the existing DMRS configuration type (Type 1, 2) may be used and only the DMRS density may be changed.

Specifically, the network may notify the UE200 of information about Density and change only the DMRS density of the set DMRS configuration type (Type 1, 2). For example, the network can notify the UE200 of "0.5" as the density scale. The UE200 may use a DMRS configuration in which the Density of DMRS is halved.

Information on DMRS density may be notified to UE200 by signaling or DCI of the upper layer as in the operation example 3.

In the case of signaling in the upper layer, for example, in the DMRS-DownlinkConfig information element or DMRS-UplinkConfig information element, it may be notified that the DMRS density is increased (or decreased).

Alternatively, when notifying the UE200 of the PDSCH / PUSCH resource, DCI may notify that the DMRS density is increased (or decreased).

More specifically, a new parameter called DMRS density scaling factor (tentative name) may be added and a bit sequence as shown in Table 1 may be assigned.

For example, if DMRS configuration type 1 is set and "2" is notified as the Scaling factor, UE200 sets the DMRS of comb1 and if "1/3" is notified as the Scaling factor, comb. You may set 6 DMRS.

(3.4.5) Operation example 5
The UE 200 may report to the network the following content as UE Capability Information regarding DMRS support with the new DMRS types or densities described above.

Specifically, the UE200 may report, for example, the following Capability for DMRS configurations with different DMRS Densities.

・ Applicability of new DMRS configuration type (Type 3, 4) ・ Applicability of High DMRS density configuration type ・ Applicability of Low DMRS density configuration type ・ Applicability of DMRS position (location) ・ Applicability of DMRS density change ・ DMRS Applicability of increase in density ・ Applicability of decrease in DMRS density UE200 may report the supported (supported) frequency (FR or band) by any of the following methods.

・ Whether or not all frequencies can be handled at once (whether or not it can be used as a mobile station)
-Availability for each frequency-Availability for each FR1 / FR2-Availability for each SCS In addition, UE200 may report the corresponding duplex method by any of the following methods.

-Whether or not it can be supported as a UE-Whether or not it can be supported for each duplex method (TDD / FDD) Furthermore, the UE200 may report the DMRS settings by any of the following methods.

-Whether or not it is possible to correspond to each length of DMRS symbol-Whether or not it is possible to correspond to each number of DMRS additional symbols (4) Actions and effects According to the above-described embodiment, the following actions and effects can be obtained. Specifically, the gNB100 and UE200 can set the DMRS arrangement in the frequency resource to the first density or a second density different from the first density. Therefore, it is possible to flexibly set the DMRS configuration that contributes to the improvement of the coverage performance. As a result, the estimation accuracy of DMRS can be improved, and the performance of coverage expansion can be improved.

In this embodiment, the type of DMRS having the first density or the type of DMRS having the second density (Types 3 and 4) can be set. Therefore, it is possible to quickly and surely set the DMRS configuration that can achieve the performance of coverage expansion.

In this embodiment, the density of DMRS can be changed by using a parameter (scaling factor) that can change the density of DMRS in the frequency direction. Therefore, the appropriate DMRS configuration can be set more flexibly.

In this embodiment, the UE200 can transmit the UE200's ability information (UECapability Information) regarding DMRS. Therefore, the DMRS configuration can be set according to the capabilities of the UE200.

(5) Other Embodiments Although the embodiments have been described above, it is obvious to those skilled in the art that various modifications and improvements are possible without limitation to the description of the embodiments.

For example, in the above-described embodiment, the demodulation reference signal (DMRS) used for channel estimation of PDSCH / PUSCH has been described, but any reference signal used for channel estimation of a physical channel such as PDSCH / PUSCH can be used. It may be a reference signal.

DMRS density may be replaced by other synonymous terms such as placement interval, placement cycle, occupancy rate, allocation frequency, etc.

Further, the block configuration diagram (FIG. 3) used in the description of the above-described embodiment shows a block of functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Further, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one physically or logically coupled device, or two or more physically or logically separated devices can be directly or indirectly (eg, for example). , Wired, wireless, etc.) and may be realized using these plurality of devices. The functional block may be realized by combining the software with the one device or the plurality of devices.

Functions include judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, selection, establishment, comparison, assumption, expectation, and assumption. Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but limited to these I can't. For example, a functional block (configuration unit) that makes transmission function is called a transmitting unit (transmitting unit) or a transmitter (transmitter). In each case, as described above, the realization method is not particularly limited.

Further, the above-mentioned gNB100 and UE200 (the device) may function as a computer for processing the wireless communication method of the present disclosure. FIG. 11 is a diagram showing an example of the hardware configuration of the device. As shown in FIG. 11, the device may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

In the following explanation, the word "device" can be read as a circuit, device, unit, etc. The hardware configuration of the device may be configured to include one or more of each of the devices shown in the figure, or may be configured not to include some of the devices.

Each functional block of the device (see FIG. 3) is realized by any hardware element of the computer device or a combination of the hardware elements.

In addition, each function in the device is such that the processor 1001 performs an operation by loading predetermined software (program) on the hardware such as the processor 1001 and the memory 1002, and controls the communication by the communication device 1004, or the memory. It is realized by controlling at least one of reading and writing of data in 1002 and storage 1003.

Processor 1001 operates, for example, an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, and the like.

Further, the processor 1001 reads a program (program code), a software module, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above-described embodiment is used. Further, the various processes described above may be executed by one processor 1001 or may be executed simultaneously or sequentially by two or more processors 1001. Processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunication line.

The memory 1002 is a computer-readable recording medium, and is composed of at least one such as ReadOnlyMemory (ROM), ErasableProgrammableROM (EPROM), Electrically ErasableProgrammableROM (EEPROM), and RandomAccessMemory (RAM). May be done. The memory 1002 may be referred to as a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, or the like that can execute the method according to the embodiment of the present disclosure.

The storage 1003 is a computer-readable recording medium, for example, an optical disk such as Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, an optical magnetic disk (for example, a compact disk, a digital versatile disk, or a Blu-ray). It may consist of at least one (registered trademark) disk), smart card, flash memory (eg, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. Storage 1003 may be referred to as auxiliary storage. The recording medium described above may be, for example, a database, server or other suitable medium containing at least one of the memory 1002 and the storage 1003.

The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like.

The communication device 1004 includes, for example, a high frequency switch, a duplexer, a filter, a frequency synthesizer, etc. in order to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). It may be composed of.

The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

In addition, each device such as the processor 1001 and the memory 1002 is connected by the bus 1007 for communicating information. Bus 1007 may be configured using a single bus or may be configured using different buses for each device.

Furthermore, the device includes hardware such as a microprocessor, a digital signal processor (Digital Signal Processor: DSP), an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), and a Field Programmable Gate Array (FPGA). The hardware may implement some or all of each functional block. For example, processor 1001 may be implemented using at least one of these hardware.

Further, the notification of information is not limited to the embodiment / embodiment described in the present disclosure, and may be performed by using another method. For example, information notification includes physical layer signaling (eg Downlink Control Information (DCI), Uplink Control Information (UCI), higher layer signaling (eg RRC signaling, Medium Access Control (MAC) signaling, Master Information Block). (MIB), System Information Block (SIB)), other signals or combinations thereof. RRC signaling may also be referred to as an RRC message, eg, RRC Connection Setup. ) Message, RRC Connection Reconfiguration message, etc. may be used.

Each aspect / embodiment described in the present disclosure includes LongTermEvolution (LTE), LTE-Advanced (LTE-A), SUPER3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system ( 5G), FutureRadioAccess (FRA), NewRadio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UltraMobileBroadband (UMB), IEEE802.11 (Wi-Fi (registered trademark)) , IEEE802.16 (WiMAX®), IEEE802.20, Ultra-WideBand (UWB), Bluetooth®, and other systems that utilize appropriate systems and at least one of the next-generation systems extended based on them. It may be applied to one. In addition, a plurality of systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A and 5G).

The order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in the present disclosure may be changed as long as there is no contradiction. For example, the methods described in the present disclosure present elements of various steps using exemplary order, and are not limited to the particular order presented.

In some cases, the specific operation performed by the base station in this disclosure may be performed by its upper node (upper node). In a network consisting of one or more network nodes having a base station, various operations performed for communication with the terminal are the base station and other network nodes other than the base station (eg, MME or). It is clear that it can be done by at least one of (but not limited to, S-GW, etc.). Although the case where there is one network node other than the base station is illustrated above, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

Information and signals (information, etc.) can be output from the upper layer (or lower layer) to the lower layer (or upper layer). Input / output may be performed via a plurality of network nodes.

The input / output information may be stored in a specific location (for example, memory) or may be managed using a management table. The input / output information may be overwritten, updated, or added. The output information may be deleted. The entered information may be transmitted to other devices.

The determination may be made by a value represented by 1 bit (0 or 1), by a boolean value (Boolean: true or false), or by comparing numerical values (for example, a predetermined value). It may be done by comparison with the value).

Each aspect / embodiment described in the present disclosure may be used alone, in combination, or may be switched and used according to the execution. Further, the notification of predetermined information (for example, the notification of "being X") is not limited to the explicit one, but is performed implicitly (for example, the notification of the predetermined information is not performed). May be good.

Software, whether called software, firmware, middleware, microcode, hardware description language, or other names, instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules. , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, features, etc. should be broadly interpreted.

Further, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, the software may use at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.) to create a website. When transmitted from a server or other remote source, at least one of these wired and wireless technologies is included within the definition of transmission medium.

The information, signals, etc. described in this disclosure may be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these. It may be represented by a combination of.

The terms described in the present disclosure and the terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Also, the signal may be a message. Further, the component carrier (CC) may be referred to as a carrier frequency, a cell, a frequency carrier, or the like.

The terms "system" and "network" used in this disclosure are used interchangeably.

Further, the information, parameters, etc. described in the present disclosure may be expressed using an absolute value, a relative value from a predetermined value, or another corresponding information. It may be represented. For example, the radio resource may be one indicated by an index.

The names used for the above parameters are not limited in any respect. Further, mathematical formulas and the like using these parameters may differ from those expressly disclosed in this disclosure. Since various channels (eg, PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements are in any respect limited names. is not.

In this disclosure, "Base Station (BS)", "Wireless Base Station", "Fixed Station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", " "Access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "cell group", " Terms such as "carrier" and "component carrier" may be used interchangeably. Base stations are sometimes referred to by terms such as macrocells, small cells, femtocells, and picocells.

A base station can accommodate one or more (eg, three) cells (also called sectors). When a base station accommodates multiple cells, the entire base station coverage area can be divided into multiple smaller areas, each smaller area being a base station subsystem (eg, a remote radio for indoor use). Communication services can also be provided by Head: RRH).

The term "cell" or "sector" refers to a base station that provides communication services in this coverage, and part or all of the coverage area of at least one of the base station subsystems.

In the present disclosure, terms such as "Mobile Station (MS)", "user terminal", "user equipment (UE)", and "terminal" may be used interchangeably. ..

Mobile stations can be used by those skilled in the art as subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless. It may also be referred to as a terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, or the like. At least one of the base station and the mobile station may be a device mounted on the mobile body, a mobile body itself, or the like. The moving body may be a vehicle (eg, car, airplane, etc.), an unmanned moving body (eg, drone, self-driving car, etc.), or a robot (manned or unmanned). ) May be. It should be noted that at least one of the base station and the mobile station includes a device that does not necessarily move during communication operation. For example, at least one of a base station and a mobile station may be an Internet of Things (IoT) device such as a sensor.

Further, the base station in the present disclosure may be read as a mobile station (user terminal, the same shall apply hereinafter). For example, communication between a base station and a mobile station has been replaced with communication between a plurality of mobile stations (for example, it may be called Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). Each aspect / embodiment of the present disclosure may be applied to the configuration. In this case, the mobile station may have the functions of the base station. Further, words such as "up" and "down" may be read as words corresponding to communication between terminals (for example, "side"). For example, the upstream channel, the downstream channel, and the like may be read as a side channel.

Similarly, the mobile station in the present disclosure may be read as a base station. In this case, the base station may have the functions of the mobile station.
The radio frame may be composed of one or more frames in the time domain. Each one or more frames in the time domain may be referred to as a subframe. Subframes may further be composed of one or more slots in the time domain. The subframe may have a fixed time length (eg, 1 ms) that does not depend on numerology.

The numerology may be a communication parameter that applies to at least one of the transmission and reception of a signal or channel. Numerology includes, for example, SubCarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (Transmission Time Interval: TTI), number of symbols per TTI, wireless frame configuration, transmission / reception. It may indicate at least one of a specific filtering process performed by the machine in the frequency domain, a specific windowing process performed by the transmitter / receiver in the time domain, and the like.

The slot may be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbol, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) in the time area. Slots may be unit of time based on numerology.

The slot may include a plurality of mini slots. Each minislot may be composed of one or more symbols in the time domain. Further, the mini-slot may be referred to as a sub-slot. A minislot may consist of a smaller number of symbols than the slot. PDSCH (or PUSCH) transmitted in time units larger than the minislot may be referred to as PDSCH (or PUSCH) mapping type A. The PDSCH (or PUSCH) transmitted using the minislot may be referred to as PDSCH (or PUSCH) mapping type B.

The wireless frame, subframe, slot, minislot and symbol all represent the time unit when transmitting a signal. The radio frame, subframe, slot, minislot and symbol may use different names corresponding to each.

For example, one subframe may be referred to as a transmission time interval (TTI), a plurality of consecutive subframes may be referred to as TTI, and one slot or one minislot may be referred to as TTI. That is, at least one of the subframe and TTI may be a subframe (1ms) in existing LTE, a period shorter than 1ms (eg, 1-13 symbols), or a period longer than 1ms. May be. The unit representing TTI may be called a slot, a mini slot, or the like instead of a subframe.

Here, TTI refers to, for example, the minimum time unit of scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate wireless resources (frequency bandwidth that can be used in each user terminal, transmission power, etc.) in TTI units. The definition of TTI is not limited to this.

The TTI may be a transmission time unit such as a channel-coded data packet (transport block), a code block, or a code word, or may be a processing unit such as scheduling or link adaptation. When a TTI is given, the time interval (for example, the number of symbols) to which the transport block, code block, code word, etc. are actually mapped may be shorter than the TTI.

When one slot or one mini slot is called TTI, one or more TTIs (that is, one or more slots or one or more mini slots) may be the minimum time unit for scheduling. Further, the number of slots (number of mini-slots) constituting the minimum time unit of the scheduling may be controlled.

A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel.8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a slot, or the like. TTIs shorter than normal TTIs may be referred to as shortened TTIs, short TTIs, partial TTIs (partial or fractional TTIs), shortened subframes, short subframes, minislots, subslots, slots, and the like.

The long TTI (for example, normal TTI, subframe, etc.) may be read as a TTI having a time length of more than 1 ms, and the short TTI (for example, shortened TTI, etc.) may be read as a TTI less than the TTI length of the long TTI and 1 ms. It may be read as a TTI having the above TTI length.

The resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or a plurality of continuous subcarriers in the frequency domain. The number of subcarriers contained in RB may be the same regardless of numerology, and may be, for example, 12. The number of subcarriers contained in the RB may be determined based on numerology.

Further, the time domain of RB may include one or more symbols, and may have a length of 1 slot, 1 mini slot, 1 subframe, or 1 TTI. Each 1TTI, 1 subframe, etc. may be composed of one or a plurality of resource blocks.

One or more RBs are physical resource blocks (Physical RB: PRB), sub-carrier groups (Sub-Carrier Group: SCG), resource element groups (Resource Element Group: REG), PRB pairs, RB pairs, etc. May be called.

Further, the resource block may be composed of one or a plurality of resource elements (ResourceElement: RE). For example, 1RE may be a radio resource area of 1 subcarrier and 1 symbol.

Bandwidth Part (BWP) (which may also be called partial bandwidth) may represent a subset of consecutive common resource blocks for a neurology in a carrier. good. Here, the common RB may be specified by the index of the RB with respect to the common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP.

BWP may include BWP for UL (UL BWP) and BWP for DL (DL BWP). One or more BWPs may be set in one carrier for the UE.

At least one of the configured BWPs may be active, and the UE may not expect to send or receive a given signal / channel outside the active BWP. In addition, "cell", "carrier" and the like in this disclosure may be read as "BWP".

The above-mentioned structures such as wireless frames, subframes, slots, mini slots and symbols are merely examples. For example, the number of subframes contained in a radio frame, the number of slots per subframe or radioframe, the number of minislots contained within a slot, the number of symbols and RBs contained in a slot or minislot, included in RB. The number of subcarriers, as well as the number of symbols in the TTI, the symbol length, the cyclic prefix (CP) length, and other configurations can be changed in various ways.

The terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or connection between two or more elements and each other. It can include the presence of one or more intermediate elements between two "connected" or "joined" elements. The connection or connection between the elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in the present disclosure, the two elements use at least one of one or more wires, cables and printed electrical connections, and, as some non-limiting and non-comprehensive examples, the radio frequency region. , Electromagnetic energies with wavelengths in the microwave and light (both visible and invisible) regions, etc., can be considered to be "connected" or "coupled" to each other.

The reference signal can also be abbreviated as Reference Signal (RS), and may be called a pilot (Pilot) depending on the applied standard.

The statement "based on" used in this disclosure does not mean "based on" unless otherwise stated. In other words, the statement "based on" means both "based only" and "at least based on".

The "means" in the configuration of each of the above devices may be replaced with a "part", a "circuit", a "device", or the like.

Any reference to elements using designations such as "first" and "second" as used in this disclosure does not generally limit the quantity or order of those elements. These designations can be used in the present disclosure as a convenient way to distinguish between two or more elements. Therefore, references to the first and second elements do not mean that only two elements can be adopted there, or that the first element must somehow precede the second element.

When "include", "including" and variations thereof are used in the present disclosure, these terms are as inclusive as the term "comprising". Is intended. Moreover, the term "or" used in the present disclosure is intended to be non-exclusive.

In the present disclosure, if articles are added by translation, for example, a, an and the in English, the disclosure may include that the nouns following these articles are plural.

The terms "determining" and "determining" used in this disclosure may include a wide variety of actions. "Judgment" and "decision" are, for example, judgment (judging), calculation (calculating), calculation (computing), processing (processing), derivation (deriving), investigation (investigating), search (looking up, search, inquiry). It may include (eg, searching in a table, database or another data structure), ascertaining as "judgment" or "decision". Also, "judgment" and "decision" are receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access. It may include (for example, accessing data in memory) to be regarded as "judgment" or "decision". In addition, "judgment" and "decision" are considered to be "judgment" and "decision" when the things such as solving, selecting, choosing, establishing, and comparing are regarded as "judgment" and "decision". Can include. That is, "judgment" and "decision" may include considering some action as "judgment" and "decision". Further, "judgment (decision)" may be read as "assuming", "expecting", "considering" and the like.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other". The term may mean that "A and B are different from C". Terms such as "separate" and "combined" may be interpreted in the same way as "different".

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure may be implemented as amendments and modifications without departing from the spirit and scope of the present disclosure as determined by the description of the scope of claims. Therefore, the description of this disclosure is for purposes of illustration and does not have any limiting meaning to this disclosure.

10 Wireless communication system 20 NG-RAN
100 gNB
110 Wireless signal transmission / reception unit 120 Amplifier unit 130 Modulation / demodulation unit 140 Control signal / reference signal processing unit 150 Coding / decoding unit 160 Data transmission / reception unit 170 Control unit 200 UE
1001 Processor 1002 Memory 1003 Storage 1004 Communication Device 1005 Input Device 1006 Output Device 1007 Bus

Claims (5)

1. A transmitter that transmits a demodulation reference signal,
   A control unit for setting the configuration of the demodulation reference signal is provided.
   The control unit is a radio base station that sets the arrangement of the demodulation reference signal in the frequency resource to the first density or a second density different from the first density.
2. The radio base station according to claim 1, wherein the control unit sets the type of the demodulation reference signal having the first density or the type of the demodulation reference signal having the second density.
3. The radio base station according to claim 1, wherein the control unit sets the density to the first density or the second density by using a parameter for changing the density of the demodulation reference signal.
4. A transmitter that transmits a demodulation reference signal,
   A terminal including a control unit that sets the arrangement of the demodulation reference signal in the frequency resource to the first density or a second density different from the first density.
5. The terminal according to claim 4, wherein the transmission unit transmits the capability information of the terminal regarding the demodulation reference signal.
   

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