Transmitter, Transmitter Method, and Integrated Circuit

Abstract

To provide a transmitting device capable of properly positioning reference signals.SOLUTION: The transmitting device includes: a control circuit that determines the arrangement of the second reference signal in the second system based on the placement of the first reference signal in the first system; and a transmission circuit that transmits a second reference signal based on the determined placement. The control circuit is configured so as to, when the position of at least one reference signal is changed in the multiple second reference signals, change the position of the remaining reference signals.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a receiving device, a transmitting device, a receiving method, and a transmitting method.

Background Art

[0002] A communication system called the 5th generation mobile communication system (5G) is under consideration. In the 3rd Generation Partnership Project (3GPP), which is an international standardization organization, the enhancement of the LTE / LTE-Advanced system and the enhancement of the 5G communication system are being considered from both aspects of a new method called New Radio Access Technology (also called New RAT or NR) that is not necessarily backward compatible with the LTE / LTE-Advanced system (see, for example, Non-Patent Document 1).

[0003] In NR, a technology (for example, DSS: Dynamic Spectrum Sharing) in which the NR system and the LTE system coexist and communicate in the same frequency band simultaneously is being considered (see, for example, Non-Patent Document 2).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

[0005] However, the method for arranging the reference signal has not been sufficiently considered.

[0006] Non-limiting embodiments of this disclosure contribute to providing a receiving device, a transmitting device, a receiving method, and a transmitting method that can appropriately position a reference signal. [Means for solving the problem]

[0007] A receiving device according to one embodiment of the present disclosure comprises a control circuit that determines the arrangement of a second reference signal in a second system based on information that can identify the arrangement of a first reference signal in a first system, and a receiving circuit that receives the second reference signal based on the determined arrangement.

[0008] Note that these general or specific aspects may be implemented in a system, apparatus, method, integrated circuit, computer program, or recording medium, or may be implemented in any combination of a system, apparatus, method, integrated circuit, computer program, and recording medium.

Advantages of the Invention

[0009] According to one embodiment of the present disclosure, a reference signal can be appropriately arranged.

[0010] Further advantages and effects in one embodiment of the present disclosure will be clarified from the specification and drawings. Such advantages and / or effects are respectively provided by several embodiments and the features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features.

Brief Description of the Drawings

[0011] [Figure 1] Diagram showing an example of DSS [Figure 2] Diagram showing an example of PDSCH mapping type B [Figure 3] Block diagram showing an example of CRS arrangement [Figure 4] Diagram showing an example of orthogonal DMRS based MU-MIMO and DSS [Figure 5] Block diagram showing a partial configuration example of a base station [Figure 6] Block diagram showing a partial configuration example of a mobile station [Figure 7] Block diagram showing a configuration example of a base station [Figure 8] Block diagram showing a configuration example of a mobile station [Figure 9] Flowchart showing an operation example of a base station and a mobile station [Figure 10] Diagram showing an example of signal arrangement according to Operation Example 1-1 [Figure 11] Diagram showing an example of signal arrangement according to Operation Example 1-2 [Figure 12]Figure showing the signal arrangement example according to Operation Example 1-3 [Figure 13] Figure showing the signal arrangement example according to Operation Example 1-4 [Figure 14] Figure showing the signal arrangement example according to Operation Example 1-4 [Figure 15] Figure showing an operation example when orthogonal DMRS based MU-MIMO is not applied [Figure 16] Figure showing the signal arrangement example according to Operation Example 2-1 [Figure 17] Figure showing the signal arrangement example according to Operation Example 2-2

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] [Dynamic Spectrum Sharing (DSS)] In DSS, the NR system and the LTE system can coexist and communicate in the same frequency band simultaneously.

[0014] For example, in the operation of DSS in Release 15 (hereinafter referred to as Rel-15), in the downlink subframe of LTE within the frequency band of LTE (or carrier), channels for LTE may be arranged. For example, as shown in FIG. 1, in the downlink subframe of LTE, control signals for LTE and reference signals (e.g., CRS: Cell-specific Reference Signal) may be arranged in one or more symbols (e.g., Orthogonal Frequency Division Multiplexing (OFDM) symbols) from the beginning, and the downlink data channel for LTE (e.g., LTE PDSCH: Physical Downlink Shared Channel) and CRS may be arranged in the remaining OFDM symbols.

[0015] In DSS, for example, during the OFDM symbol period in which an LTE PDSCH is deployed, as shown in Figure 1, an LTE PDSCH may be deployed in some frequency bands, while a Physical Downlink Control Channel (NR PDCCH) or a Physical Downlink Data Channel (NR PDSCH) for NR may be deployed in other frequency bands. In other words, the LTE PDSCH and each NR channel may be frequency-divided. However, as shown in Figure 1, CRS (sometimes called LTE CRS) may be transmitted not only in the frequency band in which the LTE PDSCH is deployed, but also in the frequency band in which each NR channel is deployed.

[0016] For example, with respect to DSS, the introduction of a mapping method for PDSCHs with lengths of 9 and 10 OFDM symbols (e.g., called NR PDSCH mapping Type B) has been proposed (see, for example, Non-Patent Document 3). For example, in this PDSCH mapping method, the position of the NR reference signal (e.g., demodulation reference signal (DMRS)) can be defined or set at the position of symbols that do not collide with symbols containing LTE CRS. The introduction of this NR PDSCH mapping Type B improves the operational efficiency of DSS.

[0017] However, such PDSCH mapping is not specified in Rel-15 (see, for example, Non-Patent Document 4), and the placement of DMRS within this PDSCH has not been sufficiently considered.

[0018] Therefore, in one embodiment of this disclosure, a method for arranging the DMRS within the PDSCH will be described.

[0019] [DMRS mapping] As an example of how to arrange DMRS in an uplink data channel (e.g., PUSCH: Physical Uplink Shared Channel), the arrangement of DMRS within NR PUSCH mapping Type B, which has lengths of 9 and 10 OFDM symbols, is specified in Non-Patent Literature 4 (e.g., Section 6.4.1.1.3).

[0020] For example, a similar placement method for DMRS in NR PDSCH mapping Type B can be applied to DMRS in NR PDSCH mapping Type B, where the lengths of the downlink data channels (e.g., PDSCH) are 9 and 10 OFDM symbols. For example, the placement method for DMRS in NR PDSCH mapping Type B with lengths of 9 and 10 OFDM symbols may be as shown in Figure 2. For example, "dmrs-AdditionalPosition" shown in Figure 2 is a higher-layer parameter (e.g., also called a radio resource control (RRC) parameter) that indicates the location of the DMRS (in other words, the Additional DMRS). dmrs-AdditionalPosition is notified (in other words, configured) from the base station (e.g., also called a gNB) to the mobile station (e.g., a terminal or UE: User Equipment).

[0021] In the following, the DMRS configuration shown in Figure 2 will be referred to as "Assumption 1". For example, in Assumption 1 shown in Figure 2, the length l d In =9 or 10, the DMRS may be placed at the first symbol (or starting symbol) "l0" where the PDSCH in the slot is scheduled, and at the symbol indicated by "dmrs-AdditionalPosition" (for example, at a position relative to l0 (=0)).

[0022] [NR DMRS shift] As mentioned above, in DSS, for example, NR PDSCH may be transmitted in the same frequency band in which LTE CRS is transmitted. In this case, the DMRS within the NR PDSCH and the LTE CRS may be designed so as not to conflict in terms of time and frequency resources (see, for example, Non-Patent Document 3).

[0023] For example, if an LTE CRS and a DMRS within an NR PDSCH configured based on "Assumption 1" may collide, the base station may transmit the DMRS at a location different from the DMRS location (in other words, resource location) configured based on "Assumption 1". Here, the process of changing the DMRS location to a location different from the location configured based on "Assumption 1" is sometimes called a "DMRS shift".

[0024] [CRS mapping] The symbol (in other words, the time-domain position) in which the CRS is placed in an LTE subframe varies depending on, for example, the number of CRS ports or the type of subframe. Subframe types include, for example, multimedia broadcast service single frequency network (MBSFN subframes) and non-MBSFN subframes. Figure 3 shows an example of how CRS is placed. For example, in an MBSFN subframe with 1 or 2 CRS ports, the CRS is transmitted using four symbols: 0, 4, 7, and 11. Also, for example, in an MBSFN subframe with 4 CRS ports, the CRS is transmitted using six symbols: 0, 1, 4, 7, 8, and 11. Furthermore, for example, in a non-MBSFN subframe, the CRS is transmitted using one symbol (0) or two symbols (0 and 1).

[0025] In this context, the first symbol in a subframe or slot is referred to as the "0th symbol."

[0026] Furthermore, the position and number of ports of the CRS in the frequency domain, as well as the timing of the MBSFN subframes, can be set at the mobile station, for example, by higher-layer parameters (e.g., the RRC parameter "RateMatchPatternLTE-CRS").

[0027] [multi-user muitiple input multiple output(MU-MIMO)] In MU-MIMO for multiple mobile stations, there is an operation where the NR DMRS ports between the mobile stations are orthogonal (for example, called orthogonal DMRS-based MU-MIMO). In the case of orthogonal DMRS-based MU-MIMO, for example, as shown in Figure 4, the NR DMRS ports between mobile station A and mobile station B are expected to be orthogonal.

[0028] Here, for example, if DSS operation is performed for mobile station A but not for mobile station B, there is a possibility that a DMRS shift will be performed for mobile station A but not for mobile station B (not shown in the diagram). In this case, since the DMRS locations are different between mobile station A and mobile station B, the orthogonality between the DMRS ports may be broken.

[0029] For example, in Rel-15, the DCI regarding antenna port mapping notifies the mobile station that "all the remaining orthogonal antenna ports are not associated with transmission of PDSCH to another UE," implicitly notifying the mobile station that orthogonal DMRS-based MU-MIMO will be in operation (see, for example, Non-Patent Document 6).

[0030] (Embodiment 1) [Overview of the communication system] The communication system according to this embodiment includes a base station (corresponding to a transmitting device) 100 and a mobile station (corresponding to a receiving device) 200.

[0031] In this embodiment, for example, the base station 100 and the mobile station 200 will describe a method for determining whether the symbol on which the DMRS is located in a slot that transmits an NR signal (e.g., PDSCH) on the downlink is changed (in other words, shifted) to a symbol different from the set symbol (e.g., a symbol based on assumption 1).

[0032] This determination allows base station 100 and mobile station 200 to suppress collisions between DMRS and CRS, even when operating orthogonal DMRS-based MU-MIMO for mobile station 200. Furthermore, base station 100 and mobile station 200 can suppress disruptions in the orthogonality of DMRS ports between mobile stations 200.

[0033] Figure 5 is a block diagram showing a partial configuration example of a base station 100 according to this embodiment. In the base station 100 shown in Figure 5, the control unit 101 (corresponding to a control circuit, for example) determines the placement of the second reference signal (e.g., DMRS) in the second system (e.g., NR system) based on information that can identify the placement of the first reference signal (e.g., CRS) in the first system (e.g., LTE system). The transmitting unit 104 (corresponding to a transmitting circuit, for example) transmits the second reference signal in the determined placement.

[0034] Figure 6 is a block diagram showing a partial configuration example of a mobile station 200 according to this embodiment. In the mobile station 200 shown in Figure 6, the control unit 206 (corresponding to a control circuit, for example) determines the placement of a second reference signal (e.g., DMRS) in a second system (e.g., an NR system) based on information that can identify the placement of a first reference signal (e.g., CRS) in a first system (e.g., an LTE system). The receiving unit 202 (corresponding to a receiving circuit, for example) receives the second reference signal based on the determined placement.

[0035] [Base station configuration] Figure 7 is a block diagram showing an example configuration of a base station 100 according to this embodiment. In Figure 7, the base station 100 includes a control unit 101, an encoding / modulation unit 102, a signal arrangement unit 103, a transmission unit 104, and an antenna 105.

[0036] The control unit 101 generates a higher-layer signal (e.g., RRC parameters) that includes parameters to be set for the mobile station 200, and outputs it to the encoding and modulation unit 102. The higher-layer signal may include, for example, information about LTE CRS (e.g., RateMatchPatternLTE-CRS) or information about the bandwidth set for the mobile station 200 (e.g., active BWP: Bandwidth part).

[0037] Furthermore, the control unit 101 determines information related to the data (e.g., PDSCH). For example, the control unit 101 determines the active BWP to which the PDSCH is transmitted, the PDSCH allocation area (e.g., called the PDSCH area), or whether or not to operate orthogonal DMRS port-based MU-MIMO. The control unit 101 then outputs downlink control information (e.g., DCI: Downlink Control Information) to the signaling unit 103, which includes information that explicitly or implicitly notifies the determined information. The control unit 101 also outputs (in other words, instructs) the determined PDSCH area to the signaling unit 103.

[0038] Furthermore, the control unit 101 determines whether or not to change (in other words, shift) the position of the DMRS within the PDSCH (for example, the position of the symbol) from its reference position (for example, the position associated with the PDSCH region; for example, the position of assumption 1 shown in Figure 2). The control unit 101 outputs information regarding the determined position of the DMRS to the signal placement unit 103.

[0039] The encoding and modulation unit 102 performs error-corrected encoding and modulation of the data (e.g., PDSCH) and the upper-layer signals input from the control unit 101, and outputs the modulated signal to the signal arrangement unit 103.

[0040] The signal placement unit 103 places (in other words, assigns or maps) the DCI input from the control unit 101 to resources in the PDCCH area, for example. The signal placement unit 103 also places the signals input from the DMRS and the encoding / modulation unit 102 to resources in the PDSCH area. The signal placement unit 103 outputs the signals placed to the resources to the transmission unit 104.

[0041] The transmitting unit 104 performs wireless transmission processing, such as frequency conversion using a carrier wave, on the signal input from the signal arrangement unit 103, and outputs the processed signal to the antenna 105.

[0042] Antenna 105 radiates the signal input from the transmitter 104 (in other words, the downlink signal) toward the mobile station 200.

[0043] [Mobile station configuration] Figure 8 is a block diagram showing an example configuration of a mobile station 200 according to this embodiment. In Figure 8, the mobile station 200 includes an antenna 201, a receiving unit 202, a signal separation unit 203, a channel estimation unit 204, a demodulation / decoding unit 205, and a control unit 206.

[0044] Antenna 201 receives the downlink signal transmitted by base station 100 (see, for example, Figure 7) and outputs it to receiving unit 202.

[0045] The receiving unit 202 performs wireless reception processing, such as frequency conversion, on the signal input from the antenna 201, and outputs the processed signal to the signal separation unit 203.

[0046] The signal separation unit 203 extracts (in other words, separates) the DCI located in the PDCCH area resources from the signal input from the receiving unit 202, and outputs the DCI to the control unit 206. The signal separation unit 203 also extracts (in other words, separates) the data signal and DMRS located in the PDSCH area resources based on the information indicating the PDSCH area resources and the information indicating the location of the DMRS input from the control unit 206. The signal separation unit 203 outputs the data signal to the demodulation / decoding unit 205 and outputs the DMRS to the channel estimation unit 204.

[0047] The channel estimation unit 204 performs channel estimation (for example, calculation of channel estimates) based on the DMRS input from the signal separation unit 203. The channel estimation unit 204 outputs information indicating the channel estimates to the demodulation / decoding unit 205.

[0048] The demodulation / decoding unit 205 demodulates and decodes the data signal input from the signal separation unit 203 based on the channel estimate value input from the channel estimation unit 204. The demodulation / decoding unit 205 outputs the upper layer signal obtained by decoding to the control unit 206.

[0049] The control unit 206 identifies, for example, the location of the PDSCH region and the DMRS associated with the PDSCH region, based on the upper layer signal input from the demodulation / decoding unit 205 and the DCI input from the signal separation unit 203.

[0050] Furthermore, the control unit 206 determines whether the position of the DMRS within the PDSCH (for example, the position of the symbol) has been changed (in other words, shifted) from its reference position (for example, the position of Assumption 1 shown in Figure 2).

[0051] The control unit 206 outputs information regarding the PDSCH area and information regarding the location of the DMRS to the signal separation unit 203.

[0052] [Example of operation of base station 100 and mobile station 200] Next, an operation example of the base station 100 (see FIG. 7) and the mobile station 200 (see FIG. 8) will be described.

[0053] FIG. 9 is a flowchart showing an example of the processing of the base station 100 and the mobile station 200.

[0054] The base station 100 notifies (in other words, sets) the upper layer signal to the mobile station 200 (ST101). The mobile station 200 receives the uplink layer signal notified from the base station 100.

[0055] The upper layer signal may include, for example, information regarding LTE CRS (e.g., RateMatchPatternLTE-CRS), or information regarding the allocated band for the mobile station 200 (e.g., active BWP). Further, for example, the information regarding the active BWP may include information regarding the subcarrier spacing (SCS) set for the mobile station 200. Note that these pieces of information may be notified to the mobile station 200 by at least one of the upper layer parameters and the downlink control information (e.g., DCI), or may be preset in the mobile station 200.

[0056] The base station 100 determines the content of the DCI to be notified to the mobile station 200 (ST102). The DCI may include, for example, the following information.

[0057] <PDSCH Allocation Information> The PDSCH allocation information may include, for example, information regarding the resources in the frequency domain to which the PDSCH (e.g., mapping type B) is allocated, and information such as the resources in the time domain where the PDSCH is arranged (e.g., start symbol and symbol length).

[0058] <PDSCH Transmission Band Information> The PDSCH transmission band information may include, for example, information regarding the BWP in which the PDSCH is transmitted (e.g., including information regarding the subcarrier spacing).

[0059] <Information related to orthogonal DMRS port based MU-MIMO> The information related to orthogonal DMRS port based MU-MIMO may include, for example, information indicating whether orthogonal DMRS port based MU-MIMO is applied to the mobile station 200. The information related to orthogonal DMRS port based MU-MIMO may be explicitly notified or implicitly notified from the base station 100 to the mobile station 200, for example.

[0060] Note that the information included in the DCI is not limited to the above-described information, and other information may be used.

[0061] The base station 100 determines whether to set (in other words, change or shift) the position of the DMRS in the PDSCH to a position different from the set position (for example, the position of "Assumption 1" shown in FIG. 2) based on the information set for the mobile station 200 (for example, the information included in the upper layer parameters and the DCI) (ST103). For example, the base station 100 may determine whether the condition for shifting the DMRS is "true" or "false".

[0062] When it is determined to shift the DMRS (ST103: YES), the base station 100 determines the position of the DMRS to a different nth symbol from the mth symbol set for the mobile station 200, for example (ST104). In other words, the position of the DMRS set for the mobile station 200 is shifted from the mth symbol to the nth symbol.

[0063] On the other hand, when it is determined not to shift the DMRS (ST103: NO), the base station 100 does not change (does not shift) the position of the DMRS.

[0064] Base station 100 transmits a downlink signal to mobile station 200 (ST105). The downlink signal may include, for example, a PDSCH including DMRS and at least one PDCCH including DCI. The DMRS is placed at a location determined by base station 100 (for example, a symbol).

[0065] The mobile station 200, for example, receives a downlink signal transmitted from the base station 100 and checks the information (in other words, the content) indicated in the DCI within the PDCCH contained in the downlink signal (ST106). For example, the mobile station 200 may determine, based on the PDSCH assignment information, that the DMRS position is set to the mth symbol.

[0066] The mobile station 200 determines, for example, based on the received upper-layer signals and the information shown in the DCI, whether the position of the DMRS in the PDSCH has been set (in other words, changed or shifted) to a different position (e.g., the nth symbol) from its set position (e.g., the mth symbol) (ST107). For example, the mobile station 200 may determine whether the condition for shifting the DMRS is "true" or "false".

[0067] If it is determined that the DMRS will be shifted (ST107: YES), the mobile station 200 determines the DMRS position to be, for example, the nth symbol, which is different from the mth symbol set for the mobile station 200 (ST108). In other words, the DMRS position set for the mobile station 200 is shifted from the mth symbol to the nth symbol.

[0068] On the other hand, if it is determined that the DMRS position should not be shifted (ST107:NO), mobile station 200 will not change (shift) the DMRS position.

[0069] The mobile station 200 performs PDSCH reception processing (e.g., demodulation processing) based on the DMRS located at the determined location (ST109).

[0070] Next, we will describe examples of the operation of the DMRS configuration according to this embodiment.

[0071] <Example of operation 1-1> Operation Example 1-1 describes, for example, how base station 100 and mobile station 200 determine whether to change (in other words, shift) the position of the DMRS, which is set to the 11th symbol (e.g., m=11) in the NR slot, to the 12th symbol (n=12).

[0072] As an example, let's consider the case where the NR PDSCH for mobile station 200 is assigned to nine symbols, from the 5th to the 13th symbol in the slot, as shown in Figure 10(a). In this case, for example, based on "Assumption 1" shown in Figure 2, the position of the DMRS in the PDSCH is set to the 11th symbol corresponding to l=6, as shown in Figure 10(a).

[0073] Furthermore, in Figure 3, for example, a CRS can be placed in the 11th symbol within the slot, while a CRS cannot be placed in the 12th symbol. Therefore, for example, by setting (in other words, changing or shifting) the position of the DMRS to the 12th symbol, which is different from the 11th symbol, collisions between the DMRS and LTE CRS within the NR PDSCH can be suppressed.

[0074] The base station 100 and the mobile station 200 will determine the DMRS location to a 12th symbol different from the 11th symbol set on the mobile station 200, as shown in Figure 10(b), if, for example, the contents indicated in the configuration information of the mobile station 200 satisfy at least one of the following conditions (for example, the processing of ST103 and ST107 shown in Figure 9). In other words, in the processing of ST103 and ST107 shown in Figure 9, the base station 100 and the mobile station 200 may determine that the condition for shifting the DMRS is "true" if the contents indicated in the information set on the mobile station 200 (for example, information that can identify (or estimate) the location of the LTE CRS) satisfy the following conditions.

[0075] Condition (1): "Mobile station 200 is not operating on an unlicensed band (also known as NR-unlicensed (NR-U))." The NR frequency band (e.g., licensed band or unlicensed band) set for the mobile station 200 may be notified to the mobile station 200 from the base station 100 by control information (e.g., upper layer signals or DCI), or it may be set in the mobile station 200.

[0076] For example, it can be assumed that DSS will not be operated in the unlicensed band. Therefore, if mobile station 200 is operating in the unlicensed band, the DMRS included in the NR signal to mobile station 200 and the LTE CRS cannot collide, so the position of DMRS (e.g., symbol 11) in the NR PDSCH does not need to be changed.

[0077] On the other hand, in the licensed band, DSS may be in operation, so for example, as shown in Figure 3, CRS may be placed in the 11th symbol in the slot. Therefore, if mobile station 200 is not operating in the unlicensed band, it can be determined that LTE CRS and DMRS may overlap.

[0078] Therefore, for example, base station 100 and mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol if condition (1) is met. In other words, base station 100 and mobile station 200 may determine the DMRS location to a 12th symbol if mobile station 200 is operating in the license band.

[0079] Condition (2): "The RRC parameter RateMatchPatternLTE-CRS is set for mobile station 200." For example, if RateMatchPatternLTE-CRS is configured on mobile station 200, an LTE CRS may be configured in the LTE system, so there is a possibility of overlap between the DMRS and LTE CRS in the NR PDSCH. For example, as shown in Figure 3, a CRS may be placed in the 11th symbol in the slot, so it can be identified that there may be an overlap between the DMRS and LTE CRS in the NR PDSCH in the 11th symbol.

[0080] Therefore, if condition (2) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0081] Condition (3): "The RRC parameter RateMatchPatternLTE-CRS is set for mobile station 200, and the timing of the MBSFN subframe set by this RRC parameter does not match the DMRS transmission timing." For example, as shown in Figure 3, in an MBSFN subframe, the CRS may be placed in the 0th or 1st symbol. Therefore, if the timing of the MBSFN subframe coincides with the transmission timing of the DMRS, the DMRS in the PDSCH and the LTE CRS cannot collide, and the position of the DMRS in the NR PDSCH (e.g., the 11th symbol) does not need to be changed.

[0082] On the other hand, if the timing of the MBSFN subframe does not match the transmission timing of the DMRS, for example, if the timing of the non-MBSFN subframe matches the transmission timing of the DMRS, then, as shown in Figure 3, the CRS may be placed in the 11th symbol, and thus it can be identified that the DMRS and LTE CRS in the PDSCH may collide.

[0083] Therefore, if condition (3) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0084] As mentioned above, in MBSFN subframes, DMRS is not placed in the 11th symbol. Therefore, condition (3) is a condition in which DMRS and CRS are more likely to collide than condition (2).

[0085] Condition (4): "Mobile station 200 uses an active BWP with a subcarrier spacing (SCS) of 15 kHz." In an NR system, if the SCS set for mobile station 200 is 15 kHz, that is, if the subcarrier spacing is the same as in an LTE system, then, for example, as shown in Figure 3, it can be identified that the DMRS and LTE CRS within the NR PDSCH may collide in the 11th symbol.

[0086] Therefore, if condition (4) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0087] Condition (5): "Orthogonal DMRS port-based MU-MIMO is in operation for mobile station 200." For example, if DCI advertises orthogonal DMRS port-based MU-MIMO to a mobile station 200, the orthogonality of the DMRS among multiple mobile stations 200 may be broken if the DMRS location changes at at least one of the multiple mobile stations 200 being MU-MIMO multiplexed.

[0088] Therefore, if condition (5) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0089] In other words, if condition (5) is met, the DMRS position for multiple mobile stations 200 operating orthogonal DMRS port-based MU-MIMO is set to the 12th symbol. This DMRS setting ensures that even if the DMRS position for a mobile station 200 operating DSS is changed, the DMRS position for other mobile stations 200 that are MU-MIMO multiplexed is also changed accordingly, thereby suppressing the breakdown of DMRS orthogonality among multiple mobile stations 200.

[0090] For example, in the example shown in Figure 4, if mobile station B is notified that orthogonal DMRS port-based MU-MIMO is in operation, mobile station B may determine the DMRS location to the 12th symbol, taking into consideration that even if DSS is not in operation for mobile station B, DSS may be in operation for other mobile stations A that are MU-MIMO multiplexed.

[0091] Condition (5) may also be defined, for example, as "it implies that the DCI received by mobile station 200 is orthogonal DMRS port based MU-MIMO."

[0092] Condition (6): "The DCI received by mobile station 200 is notifying of an assignment via PDSCH mapping type B." In assignment using PDSCH mapping type B, for example, as shown in Figure 2, d In the case of l=9, the 11th symbol corresponding to l=6 may be occupied by the DMRS within the PDSCH. Also, as shown in Figure 3, for example, the 11th symbol in the slot may be occupied by the CRS. Therefore, when PDSCH mapping type B is set, the 11th symbol may be occupied by the DMRS within the NR PDSCH and the LTE CRS.

[0093] Therefore, if condition (6) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0094] Condition (7): "The DCI received by mobile station 200 notifies of an assignment by PDSCH mapping type B, and the assignment is '9 symbols from the 5th symbol to the 13th symbol'." As explained in condition (6), in the assignment by PDSCH mapping type B, the length of the PDSCH is 9 symbols (for example, as shown in Figure 2, l d In the case of l=9), the 11th symbol corresponding to l=6 may be occupied by the DMRS within the PDSCH. Also, as shown in Figure 3, for example, the 11th symbol in the slot may be occupied by the CRS. Therefore, when PDSCH mapping type B is set, the 11th symbol may be occupied by the DMRS within the NR PDSCH and the LTE CRS.

[0095] Therefore, if condition (7) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 12th symbol different from the 11th symbol.

[0096] For example, as shown in Figure 2, in single symbol DMRS, the length of PDSCH is 10 symbols (for example, as shown in Figure 2, l d In the case of =10), DMRS is not placed in the 11th symbol (corresponding to l=7). Therefore, condition (7) is a condition in which DMRS and CRS are more likely to collide than condition (6).

[0097] The above explains each of the conditions (1) to (7).

[0098] The base station 100 and the mobile station 200 may, for example, determine whether to assign the DMRS location to the 11th symbol or the 12th symbol based on one or more of the conditions (1) to (7).

[0099] According to example 1-1, for instance, the base station 100 and the mobile station 200, based on the information set in the mobile station 200, determine (in other words, change or shift) the position of the DMRS in the NR PDSCH to the 12th symbol that does not conflict with the CRS if a collision between the DMRS and the LTE CRS is possible. This determination of the DMRS position helps to avoid collisions between the DMRS and the LTE CRS in the NR PDSCH.

[0100] Furthermore, for example, if the base station 100 and the mobile station 200 satisfy at least one of the above conditions (1) to (7), it may be determined that orthogonal DMRS-based MU-MIMO can be operated for the mobile station 200.

[0101] For example, base station 100 performs a DMRS shift for each of the multiple mobile stations 200 operating on orthogonal DMRS-based MU-MIMO. Furthermore, each mobile station 200 operating on orthogonal DMRS-based MU-MIMO anticipates that a DMRS shift may be performed on other mobile stations 200 that are multiplexed with MU-MIMO to avoid collisions between DMRS and CRS, and determines that a DMRS shift should also be performed on the mobile station 200. This determination reduces the disruption of orthogonality between the DMRS ports corresponding to each of the multiple mobile stations 200 when orthogonal DMRS-based MU-MIMO is operated for the mobile stations 200.

[0102] Based on the above, according to Operation Example 1-1, for example, a collision between DMRS and CRS can be avoided. Also, according to Operation Example 1-1, for example, the orthogonality between DMRS ports can be maintained.

[0103] In example 1-1, the case where m=11 and n=12 was described, but the position of the DMRS after the change (in other words, after the shift) is not limited to the 12th symbol, but may be a symbol from the 13th symbol onwards, or a symbol from the 10th symbol or the 9th symbol onwards. By changing to these symbols, the DMRS can be flexibly positioned at a temporal position or interval suitable for improving the channel estimation accuracy at, for example, the mobile station 200.

[0104] <Example of operation 1-2> Example 1-2 describes, for example, how base station 100 and mobile station 200 determine whether to change (in other words, shift) the position of the DMRS, which is set to the 8th symbol (e.g., m=8) in the NR slot, to the 9th symbol (e.g., n=9).

[0105] As an example, let's consider the case where the NR PDSCH for mobile station 200 is assigned to nine symbols, from the 5th to the 13th symbol in the slot, as shown in Figure 11(a). In this case, for example, based on "Assumption 1" shown in Figure 2, the position of the DMRS in the PDSCH is set to the 8th symbol corresponding to l=3, as shown in Figure 11(a).

[0106] Furthermore, in Figure 3, for example, a CRS can be placed in the 8th symbol within the slot, while a CRS cannot be placed in the 9th symbol. Therefore, for example, by setting (in other words, changing or shifting) the position of the DMRS to the 9th symbol, which is different from the 8th symbol, collisions between the DMRS and LTE CRS within the NR PDSCH can be suppressed.

[0107] In Operation Example 1-2, the base station 100 and the mobile station 200 determine the DMRS location to a 9th symbol different from the 8th symbol set on the mobile station 200, as shown in Figure 11(b), if, for example, the contents shown in the configuration information of the mobile station 200 satisfy at least one of the conditions (1) to (7) described in Operation Example 1-1, and the following condition (8). (For example, the processing of ST103 and ST107 shown in Figure 9).

[0108] Condition (8): Condition (8) is when "the RRC parameter RateMatchPatternLTE-CRS is set for mobile station 200, the number of CRS ports set by this RRC parameter is 4, and the timing of the MBSFN subframe set by this RRC parameter does not match the DMRS transmission timing."

[0109] One example of a case where condition (8) is met is when the timing of a non-MBSFN subframe coincides with the transmission timing of the DMRS. For example, as shown in Figure 3, if the number of CRS ports is 4, and the CRS may be located in the 8th symbol in a non-MBSFN subframe, then the DMRS in the NR PDSCH and the LTE CRS may overlap in the 8th symbol.

[0110] Therefore, if condition (8) is met, the base station 100 and the mobile station 200 may determine the DMRS location to a 9th symbol different from the 8th symbol.

[0111] The base station 100 and the mobile station 200 may, for example, determine whether to assign the DMRS location to the 8th symbol or the 9th symbol based on one or more of the conditions (1) to (8).

[0112] According to example 1-2, for instance, the base station 100 and the mobile station 200, based on the information set in the mobile station 200, determine (in other words, change or shift) the position of the DMRS in the NR PDSCH to the 9th symbol, which does not conflict with the CRS, if the DMRS and LTE CRS in the NR PDSCH could potentially collide. This determination of the DMRS position helps to avoid collisions between the DMRS and LTE CRS in the NR PDSCH.

[0113] Furthermore, for example, if the base station 100 and the mobile station 200 satisfy at least one of the above conditions (1) to (8), it may be determined that orthogonal DMRS-based MU-MIMO can be operated for the mobile station 200.

[0114] For example, base station 100 performs a DMRS shift for each of the multiple mobile stations 200 operating on orthogonal DMRS-based MU-MIMO. Furthermore, each mobile station 200 operating on orthogonal DMRS-based MU-MIMO anticipates that a DMRS shift may be performed on other mobile stations 200 that are multiplexed with MU-MIMO to avoid collisions between DMRS and CRS, and determines that a DMRS shift should also be performed on the mobile station 200. This determination reduces the disruption of orthogonality between the DMRS ports corresponding to each of the multiple mobile stations 200 when orthogonal DMRS-based MU-MIMO is operated for the mobile stations 200.

[0115] Based on the above, according to Operation Example 1-2, for example, collisions between DMRS and CRS can be avoided. Furthermore, according to Operation Example 1-2, for example, the orthogonality between DMRS ports can be maintained.

[0116] In operation example 1-2, the cases of m=8 and n=9 were explained, but the position of the DMRS after the change (in other words, after the shift) is not limited to the 9th symbol, but may also be the 10th or 11th symbol or later, or the 7th or 6th symbol or earlier. By changing to these symbols, the DMRS can be flexibly positioned at a temporal position or interval suitable for improving the channel estimation accuracy at, for example, the mobile station 200.

[0117] <Example of operation 1-3> Operation Example 1-3 describes, for example, how base station 100 and mobile station 200 determine whether to change (in other words, shift) the positions of the DMRS (in other words, double symbol DMRS) set to the 10th and 11th symbols (e.g., m=10 and 11) in the NR slot to the 12th and 13th symbols (e.g., n=12 and 13).

[0118] As an example, let's consider the case where the NR PDSCH for mobile station 200 is assigned to nine symbols, from the 5th to the 13th symbol in the slot, as shown in Figure 12(a). In this case, for example, based on "Assumption 1" shown in Figure 2, the position of the DMRS in the PDSCH is set to the 10th and 11th symbols, corresponding to l=5, as shown in Figure 12(a).

[0119] Furthermore, in Figure 3, for example, a CRS can be placed in the 8th symbol within the slot, while a CRS cannot be placed in the 9th symbol. Therefore, for example, by setting (in other words, changing or shifting) the position of the DMRS to the 9th symbol, which is different from the 8th symbol, collisions between the DMRS and LTE CRS within the NR PDSCH can be suppressed.

[0120] In Operation Example 1-3, the base station 100 and the mobile station 200, for example, if the contents shown in the configuration information of the mobile station 200 satisfy at least one of the conditions (1) to (7) described in Operation Example 1-1, determine the DMRS location to the 12th and 13th symbols, which are different from the 10th and 11th symbols set on the mobile station 200, as shown in Figure 12(b) (for example, the processing of ST103 and ST107 shown in Figure 9).

[0121] The base station 100 and the mobile station 200 may, for example, determine whether to set the DMRS location to the 10th and 11th symbols or the 12th and 13th symbols based on any one or more of the conditions (1) to (7).

[0122] According to Operation Example 1-3, for example, the base station 100 and the mobile station 200, based on the information set in the mobile station 200, determine (in other words, change or shift) the position of the double symbol DMRS in the NR PDSCH to the 12th and 13th symbols that do not conflict with the CRS if a collision between the DMRS and LTE CRS is possible. This determination of the DMRS position can avoid a collision between the double symbol DMRS and LTE CRS in the NR PDSCH.

[0123] Furthermore, similar to example 1-1, if, for example, the base station 100 and the mobile station 200 satisfy at least one of the above conditions (1) to (7), it may be determined that orthogonal DMRS-based MU-MIMO can be operated for the mobile station 200.

[0124] For example, base station 100 performs a DMRS shift for each of the multiple mobile stations 200 operating on orthogonal DMRS-based MU-MIMO. Furthermore, each mobile station 200 operating on orthogonal DMRS-based MU-MIMO anticipates that a DMRS shift may be performed on other mobile stations 200 that are multiplexed with MU-MIMO to avoid collisions between DMRS and CRS, and determines that a DMRS shift should also be performed on the mobile station 200. This determination reduces the disruption of orthogonality between the DMRS ports corresponding to each of the multiple mobile stations 200 when orthogonal DMRS-based MU-MIMO is operated for the mobile stations 200.

[0125] Based on the above, according to Operation Example 1-3, for example, collisions between double symbol DMRS and CRS can be avoided. Furthermore, according to Operation Example 1-3, for example, the orthogonality between DMRS ports can be maintained.

[0126] In operation example 1-3, the cases of m=10 and 11, and n=12 and 13 were explained, but the position of the DMRS after the change (in other words, after the shift) is not limited to the 12th and 13th symbols, but may also be, for example, the 9th and 10th symbols, or the two symbols before the 9th symbol. By changing to these symbols, the DMRS can be flexibly positioned at a temporal position or interval suitable for improving the channel estimation accuracy at, for example, the mobile station 200.

[0127] <Example of operation 1-4> Example 1-4 describes, for example, how base station 100 and mobile station 200 determine whether to change (in other words, shift) the position of the DMRS, which is set to the 8th symbol (e.g., m=8) in the NR slot, to the 10th symbol (e.g., n=10).

[0128] In example 1-4, for instance, an active BWP with a subcarrier interval of 30 kHz may be set for the mobile station 200 (for example, the processing of ST101 shown in Figure 9).

[0129] Furthermore, the base station 100 may assign NR PDSCH to the mobile station 200, for example, to nine symbols from the 5th to the 13th symbol in the slot, as shown in Figure 11(a), or to ten symbols from the 4th to the 13th symbol in the slot, as shown in Figure 13 (for example, the processing of ST102 shown in Figure 9).

[0130] Furthermore, for example, base station 100 may assign a PDSCH to mobile station 200 with an active BWP having a subcarrier interval of 30 kHz (for example, the processing of ST102 shown in Figure 9).

[0131] Furthermore, the base station 100 may configure the mobile station 200 to operate orthogonal DMRS port-based MU-MIMO (for example, the process of ST102 shown in Figure 9).

[0132] For example, based on "Assumption 1" shown in Figure 2, as shown in Figures 11(a) and 13, l d =9 l=3 or l d The position of DMRS within PDSCH is set to the 8th symbol corresponding to l=4 in =10.

[0133] When the SCS for NR is 30kHz, the time required for one symbol is half that of LTE with an SCS of 15kHz. In other words, one symbol with an SCS of 15kHz is equivalent to two symbols with an SCS of 30kHz.

[0134] For example, in Figure 3, the fourth symbol (or eleventh symbol) where the CRS is located in LTE with SCS=15kHz corresponds to the eighth and ninth symbols in NR with SCS=30kHz. Therefore, for example, the CRS can be located in the eighth and ninth symbols in the NR slot with SCS=30kHz, at a position corresponding to the fourth symbol (or eleventh symbol) in SCS=15kHz. In contrast, the CRS cannot be located in the tenth symbol in the NR slot with SCS=30kHz (for example, corresponding to the fifth or twelfth symbol in SCS=15kHz). Therefore, for example, by setting (in other words, changing or shifting) the position of the DMRS in the NR slot with SCS=30kHz to the tenth symbol, which is different from the eighth symbol, collisions between the DMRS in the NR PDSCH and the LTE CRS can be suppressed.

[0135] In Operation Example 1-4, the base station 100 and the mobile station 200 determine the DMRS location to a 10th symbol different from the 8th symbol, as shown in Figures 14(a) and 14(b), if, for example, the contents shown in the configuration information of the mobile station 200 satisfy at least one of the conditions (1) to (3), (5), (6) described in Operation Example 1-1, and the following conditions (4)' and (7)'.

[0136] Condition (4)': "Mobile station 200 uses an active BWP with a subcarrier spacing (SCS) of 30 kHz." As mentioned above, if the SCS for NR is 30kHz, the 8th symbol in the NR slot may conflict with the DMRS and LTE CRS in the NR PDSCH.

[0137] Therefore, if condition (4)' is met, the base station 100 and the mobile station 200 may determine the position of the DMRS to be a 10th symbol different from the 8th symbol (for example, a symbol one symbol later at SCS=15kHz).

[0138] Condition (7)': "The DCI received by mobile station 200 notifies of an assignment by PDSCH mapping type B, and the assignment is either '9 symbols from the 5th to the 13th symbol' or '10 symbols from the 4th to the 13th symbol'." As mentioned above, in the assignment using PDSCH mapping type B, the length of the PDSCH is 9 symbols (for example, as shown in Figure 2, l d In the case of =9), l=3, and the length of PDSCH is 10 symbols (for example, l shown in Figure 2). d In the case of l=10), the 8th symbol corresponding to l=4 may be where the DMRS within the PDSCH is located. Also, as mentioned above, the 4th or 11th symbol in the slot at SCS=15kHz, which corresponds to the 8th symbol at SCS=30kHz, may be where the CRS is located. Therefore, when PDSCH mapping type B is set, and the PDSCH length is 9 symbols or 10 symbols, the 8th symbol in the NR slot may collide with the DMRS within the NR PDSCH and the LTE CRS.

[0139] Therefore, if condition (7)' is met, the base station 100 and the mobile station 200 may determine the position of the DMRS to be a 10th symbol different from the 8th symbol (for example, a symbol one symbol later at SCS=15kHz).

[0140] The base station 100 and the mobile station 200 may determine whether to assign the DMRS location to the 8th symbol or the 10th symbol based on, for example, one or more of the following conditions: (1) to (3), (4)', (5), (6), and (7)'.

[0141] According to Operation Example 1-4, for example, the base station 100 and the mobile station 200, based on the information set in the mobile station 200, determine (in other words, change or shift) the position of the DMRS in the NR PDSCH to a 10th symbol that does not conflict with the CRS if a collision between the DMRS and the LTE CRS is possible. This determination of the DMRS position makes it possible to avoid collisions between the DMRS in the NR PDSCH and the LTE CRS, even if the NR SCS is different from the LTE SCS.

[0142] Furthermore, for example, if the base station 100 and the mobile station 200 satisfy at least one of the above conditions (1) to (3), (4)', (5), (6), and (7)', it may be determined that orthogonal DMRS-based MU-MIMO can be operated for the mobile station 200.

[0143] For example, base station 100 performs a DMRS shift for each of the multiple mobile stations 200 operating on orthogonal DMRS-based MU-MIMO. Furthermore, each mobile station 200 operating on orthogonal DMRS-based MU-MIMO anticipates that a DMRS shift may be performed on other mobile stations 200 that are multiplexed with MU-MIMO to avoid collisions between DMRS and CRS, and determines that a DMRS shift should also be performed on the mobile station 200. This determination reduces the disruption of orthogonality between the DMRS ports corresponding to each of the multiple mobile stations 200 when orthogonal DMRS-based MU-MIMO is operated for the mobile stations 200.

[0144] Based on the above, according to Operation Example 1-4, for example, collisions between DMRS and CRS can be avoided. Furthermore, according to Operation Example 1-4, for example, the orthogonality between DMRS ports can be maintained.

[0145] In operation example 1-4, the case where m=8 and n=10 was explained, but the position of the DMRS after the change (in other words, after the shift) is not limited to the 10th symbol, but may be, for example, the 11th symbol or the 12th symbol or later, or the 7th symbol or the 6th symbol or earlier. By changing to these symbols, the DMRS can be flexibly positioned at a temporal position or interval suitable for improving the channel estimation accuracy at, for example, the mobile station 200.

[0146] As described above, in operation examples 1-1 to 1-4, we explained, as an example, the case in which the position of the DMRS is determined based on the position of the DMRS and the position of the CRS that can be set for the mobile station 200 in Rel. 16. In other words, in operation examples 1-1 to 1-4, for example, the base station 100 and the mobile station 200 can identify symbols that may or may not conflict between the DMRS and CRS, based on the setting information of the mobile station 200.

[0147] For example, the conditions described in operation examples 1-1 to 1-4 do not depend on whether the symbols on which CRS is placed and the symbols set for DMRS for the mobile station 200 overlap (in other words, collide). Therefore, in operation examples 1-1 to 1-4, if the above conditions are met, the base station 100 and the mobile station 200 can maintain orthogonality between the DMRS ports corresponding to multiple mobile stations 200 that are MU-MIMO multiplexed, for example, by changing the placement of the DMRS, even if CRS and DMRS do not actually collide.

[0148] <Example 1-5> Operation Example 1-5 describes an example of operation in a case where, for example, the base station 100 and the mobile station 200 cannot determine whether or not there is a collision between DMRS and CRS based on the configuration information of the mobile station 200.

[0149] For example, Operation Example 1-5 describes how the base station 100 and the mobile station 200 determine whether to change (in other words, shift) the position of the DMRS, which is set to an arbitrary symbol in the NR slot, to a different symbol.

[0150] In example 1-5, for instance, an active BWP with a subcarrier interval of 15 kHz, 30 kHz, or 60 kHz may be set for the mobile station 200 (for example, the processing of ST101 shown in Figure 9).

[0151] Furthermore, the base station 100 may assign an NR PDSCH to the mobile station 200, for example, in a frequency band on which LTE CRS can be transmitted, and in any time resource within the slot (for example, the process of ST102 shown in Figure 9).

[0152] Furthermore, for example, base station 100 may assign a PDSCH to mobile station 200 to an active BWP having a subcarrier interval of 15 kHz, 30 kHz, or 60 kHz (for example, the processing of ST102 shown in Figure 9).

[0153] Furthermore, the base station 100 may configure the mobile station 200 to operate orthogonal DMRS port-based MU-MIMO (for example, the process of ST102 shown in Figure 9).

[0154] For example, let's define the position of the DMRS within the PDSCH, as set based on "Assumption 1" shown in Figure 2, as the "xth symbol".

[0155] The base station 100 determines, for example, whether to change (in other words, shift) the position of the DMRS to a symbol different from the x-th symbol set on the mobile station 200 (hereinafter referred to as the "y-th symbol") (for example, the process of ST103 shown in Figure 9). For example, if the symbol on which the CRS is located overlaps with the x-th symbol set on the mobile station 200, the base station 100 may determine the position of the DMRS to be a symbol different from the x-th symbol, the y-th symbol.

[0156] For example, base station 100 may determine whether the symbol on which the CRS is located and the x-th symbol on which the DMRS is located overlap, based on information regarding LTE CRS (e.g., information regarding the placement of CRS) and information regarding resources set on mobile station 200 (e.g., information regarding frequency domain and time domain allocation resources for PDSCH). In other words, base station 100 determines whether the CRS and DMRS may collide in the x-th symbol. If base station 100 determines, for example, that the CRS and DMRS may collide, it may determine that the condition for shifting the DMRS is "true".

[0157] If the condition for shifting the DMRS is true (ST103: YES), base station 100 determines (in other words, changes or shifts) the position of the DMRS to the yth symbol, which is different from the xth symbol (ST104). For example, base station 100 may place (in other words, shift) the DMRS to the yth symbol, which has a smaller symbol number among the symbols that do not conflict with the CRS among the symbols after the xth symbol.

[0158] Furthermore, if there are no symbols after the x-th symbol that do not conflict with the CRS, base station 100 may place the DMRS at the x-th symbol (in other words, it will not shift).

[0159] Furthermore, the mobile station 200 determines whether to change the DMRS position (x-th symbol) to a different position (y-th symbol) from the position (x-th symbol) set based on the control signal notified from the base station 100 (for example, the process of ST107 shown in Figure 9). For example, if the symbol on which the CRS is located overlaps with the x-th symbol set on the mobile station 200, the mobile station 200 may determine the DMRS position to be a different y-th symbol from the x-th symbol.

[0160] For example, the mobile station 200, like the base station 100, determines whether the symbol on which the CRS is located and the x-th symbol on which the DMRS is located may overlap (in other words, collide) based on information regarding the LTE CRS and the PDSCH assignment information set on the mobile station 200. If the mobile station 200 determines, for example, that the CRS and DMRS may collide, it may determine that the condition for shifting the DMRS is "true".

[0161] If the condition for shifting the DMRS is true (ST107: YES), the mobile station 200 determines that the position of the DMRS has been determined (in other words, changed or shifted) to a symbol y that is different from the x-th symbol (ST108). For example, the mobile station 200 may determine that the DMRS has been placed (in other words, shifted) to the y-th symbol, which has a smaller symbol number among the symbols that do not conflict with the CRS among the symbols after the x-th symbol.

[0162] Furthermore, if there are no symbols after the xth symbol that do not conflict with the CRS, mobile station 200 may determine that the DMRS is located at the xth symbol (in other words, it may determine that there is no shift).

[0163] According to Operation Example 1-5, for example, if the base station 100 and mobile station 200 are in danger of a collision between the DMRS and LTE CRS in the NR PDSCH, they will determine (in other words, change or shift) the position of the DMRS in the NR PDSCH to another symbol that does not collide with the CRS. This determination of the DMRS position helps to avoid a collision between the DMRS and LTE CRS in the NR PDSCH.

[0164] Note that the subcarrier interval set for mobile station 200 is not limited to 15kHz, 30kHz, and 60kHz; other intervals may also be used.

[0165] Furthermore, in operation example 1-5, the y-th symbol is not limited to the smallest numbered symbol among the symbols that do not conflict with the CRS from the x-th symbol onward. For example, it could be the second smallest numbered symbol, or the third smallest numbered symbol or later among the symbols that do not conflict with the CRS. Alternatively, the y-th symbol could be any symbol prior to the x-th symbol that does not conflict with the CRS. These changes to symbols allow for flexible placement of the DMRS at a temporal position or interval suitable for improving the channel estimation accuracy at, for example, the mobile station 200.

[0166] Furthermore, in addition to determining whether DMRS and CRS may conflict, base station 100 and mobile station 200 may also determine whether to change the location of the DMRS set on mobile station 200, for example, based on whether the contents shown in the configuration information of mobile station 200 satisfy at least one of the above-mentioned conditions (1), (3), (5), and (8).

[0167] Furthermore, for example, if the base station 100 and the mobile station 200 satisfy at least one of the above conditions (1), (3), (5), and (8), it may be determined that orthogonal DMRS-based MU-MIMO can be operated for the mobile station 200. For example, the base station 100 performs a DMRS shift for each of the multiple mobile stations 200 on which orthogonal DMRS-based MU-MIMO is operated. In addition, each mobile station 200 on which orthogonal DMRS-based MU-MIMO is operated assumes that a DMRS shift may be performed for the other mobile stations 200 that are multiplexed with MU-MIMO to avoid collisions between DMRS and CRS, and determines that a DMRS shift will also be performed for that mobile station 200. This determination reduces the disruption of orthogonality between the DMRS ports corresponding to each of the multiple mobile stations 200 when orthogonal DMRS-based MU-MIMO is operated for the mobile station 200.

[0168] The above describes an example of how DMRS can be deployed and operated.

[0169] Thus, in this embodiment, the base station 100 and the mobile station 200 determine the placement of the DMRS within the NR PDSCH based on information set in the mobile station 200 (in other words, information that can identify the placement of the LTE CRS). This determination of the DMRS placement allows, for example, the base station 100 operating DSS to appropriately place the DMRS and avoid collisions between the DMRS and CRS. Furthermore, this determination of the DMRS placement allows, for example, the maintenance of orthogonality between DMRS ports. In addition, even when DSS is in operation, the mobile station 200 can appropriately determine the placement of the DMRS and receive the NR PDSCH.

[0170] (Variation 1 of Embodiment 1) In Embodiment 1, if DMRS is placed in multiple symbols within a slot, the base station 100 and the mobile station 200 may simultaneously change (in other words, shift) the multiple symbols on which DMRS is placed.

[0171] For example, if the DMRS locations in "Assumption 1" shown in Figure 2 are symbols 8 and 11, the base station 100 and the mobile station 200 may change the respective DMRS locations to symbols 9 and 12.

[0172] This change in DMRS configuration allows for avoidance of conflicts with CRS across multiple DMRS systems.

[0173] (Variation 2 of Embodiment 1) In Embodiment 1, for example, the information regarding the LTE system (e.g., RRC parameter RateMatchPatternLTE-CRS) notified from the base station 100 to the mobile station 200 in the processing of ST101 shown in Figure 9 may also be information regarding the CRS of an LTE component carrier (CC) operating in any of the following frequency bands. (1) System bandwidth of the NR component carrier on which the base station 100 and mobile station 200 operate (2) Any BWP set on mobile station 200 (3) Active BWP used for transmission to mobile station 200 (4) Allocated bandwidth of the PDSCH transmitted to mobile station 200

[0174] Furthermore, if there are multiple LTE component carriers within the above frequency band, the base station 100 may notify the mobile station 200 of parameters indicating information regarding CRS in one or more LTE component carriers.

[0175] For example, if multiple parameters are notified, the base station 100 and the mobile station 200 may decide whether or not to change the DMRS location based on one or more parameters (for example, the processes of ST103 and ST107 shown in Figure 9).

[0176] Furthermore, the base station 100 and the mobile station 200 may decide whether or not to change the location of the DMRS based on some of several parameters. For example, the base station 100 and the mobile station 200 may operate based on a parameter that includes a larger number of CRS ports, or on a parameter that has a higher frequency of non-MBSFN subframes. These operations can reduce the possibility of collisions between CRS and DMRS by determining the location of the DMRS, for example, taking into account situations where CRS may be deployed to more resources.

[0177] Furthermore, the base station 100 may notify the mobile station 200 of parameters used when deciding whether or not to change the DMRS location.

[0178] (Variation 3 of Embodiment 1) In Embodiment 1, the conditions for determining whether or not to change the location of the DMRS may be, for example, information known between the base station 100 and the mobile station 200, or information notified from the base station 100 to the mobile station 200 by a control signal such as a higher layer signal or DCI.

[0179] Alternatively, information indicating the result of the decision on whether or not to change the DMRS location may be notified from the base station 100 to the mobile station 200 by a control signal such as a higher-layer signal or DCI.

[0180] This notification allows the mobile station 200 to accurately determine whether the location of the DMRS transmitted by the base station 100 has changed.

[0181] (Variation 4 of Embodiment 1) In Embodiment 1, the fact that the mobile station 200 is operating with orthogonal DMRS port-based MU-MIMO may be implicitly indicated, for example, by a DCI related to antenna port mapping that indicates "all the remaining orthogonal antenna ports are not associated with transmission of PDSCH to another UE".

[0182] (Variation 5 of Embodiment 1) In Embodiment 1, as shown in Figure 15, the position of the DMRS received by the mobile station 200, which does not operate orthogonal DMRS-based MU-MIMO, may be shifted. This can mitigate, for example, the degradation of reception accuracy due to DMRS collisions between cells.

[0183] (Variation 6 of Embodiment 1) In Embodiment 1, the parameters included in the conditions for each of the above operation examples are not limited to RateMatchPatternLTE-CRS, but may be, for example, parameters related to at least CRS or MBSFN subframes, and may be higher-layer parameters with different names from RateMatchPatternLTE-CRS, or parameters included in control signals such as DCI.

[0184] (Embodiment 2) For example, when multiple DMRSs are arranged within a slot, as described in Embodiment 1, a change in the position of a DMRS that may collide with a CRS can alter the positional relationship (e.g., time interval) between the relocated DMRS and the other DMRSs (in other words, DMRS whose positions have not been changed).

[0185] For example, the greater the time interval between DMRSs, the more the accuracy of channel estimation between those DMRSs may deteriorate.

[0186] Furthermore, for example, the smaller the time interval between DMRSs, the less effective it may be to place DMRSs in multiple symbols. In other words, the smaller the time interval between DMRSs, the greater the overhead caused by DMRSs, and the lower the resource utilization efficiency may be.

[0187] This embodiment describes a method for deploying a DMRS that suppresses the degradation of channel estimation accuracy, and a method for deploying a DMRS that improves resource utilization efficiency.

[0188] Furthermore, the base station and mobile station according to this embodiment share the same basic configuration as the base station 100 and mobile station 200 according to Embodiment 1.

[0189] Next, we will describe examples of the operation of the DMRS configuration according to this embodiment.

[0190] <Example of operation 2-1> In example 2-1, for instance, when multiple DMRS symbols are placed in a slot, the base station 100 and the mobile station 200 change (in other words, shift) the positions of DMRS that may or may not collide with CRS, as well as DMRS that may not collide with CRS.

[0191] As an example, we will explain the case where, as shown in Figure 16(a), NR PDSCH is assigned to 9 symbols from the 5th to the 13th symbol within a BWP with a subcarrier interval of 15 kHz for mobile station 200.

[0192] In this case, for example, based on "Assumption 1" shown in Figure 2, the positions of DMRS within PDSCH are set to the 5th, 8th, and 11th symbols (l=0,3,6).

[0193] Furthermore, for example, the base station 100 and the mobile station 200 determine that the CRS may be placed in at least the 7th, 8th, and 11th symbols within the slot, as shown in Figure 3.

[0194] In this case, the base station 100 and the mobile station 200 determine, for example, that DMRS and CRS may collide in the 8th and 11th symbols.

[0195] Therefore, base station 100 may change (in other words, shift) the positions of the DMRS that may be placed in the 8th and 11th symbols, and the positions of the DMRS that may be placed in the 5th symbol. For example, base station 100 may change the DMRS of the 5th, 8th and 11th symbols shown in Figure 16(a) to the 6th, 9th and 12th symbols, respectively, as shown in Figure 16(b).

[0196] Furthermore, the mobile station 200, like the base station 100, may determine that the DMRS for symbols 5, 8, and 11 shown in Figure 16(a) are located for symbols 6, 9, and 12, respectively, as shown in Figure 16(b).

[0197] In Operation Example 2-1, if the base station 100 and the mobile station 200 change the position of at least one DMRS in a slot, for example, they change the positions of the remaining DMRS based on that DMRS position (in other words, the change in position). For example, as shown in Figures 16(a) and 16(b), the three DMRS in the PDSCH are each shifted one symbol backward from the position set by the mobile station 200 (e.g., the position based on "Assumption 1"). In other words, as shown in Figure 16(b), the spacing between the changed DMRS (e.g., 3 symbols) remains the same as the spacing between the DMRS before the change (e.g., 3 symbols).

[0198] This DMRS configuration ensures that even when the DMRS locations are changed, the time-domain spacing between multiple DMRSs remains constant, thus suppressing the degradation of channel estimation accuracy by DMRS.

[0199] <Example of operation 2-2> In example 2-2, for instance, if DMRSs are placed in multiple symbols within a slot, the base station 100 and mobile station 200 decide to de-transmit (in other words, drop) one of the two DMRSs whose time interval is below a threshold in the determined DMRS placement (in other words, the changed position).

[0200] As an example, we will explain the case in which NR PDSCH is assigned to 9 symbols, from the 5th symbol to the 13th symbol, within a BWP with a subcarrier interval of 30 kHz, as shown in Figure 17(a).

[0201] Furthermore, here, the threshold for the time interval between DMRSs used to determine whether or not to drop a DMRS is set to 1 symbol. Note that the threshold is not limited to 1 symbol; it may be 2 or more symbols.

[0202] In this case, for example, based on "Assumption 1" shown in Figure 2, the positions of DMRS within PDSCH are set to the 5th, 8th, and 11th symbols (l=0,3,6).

[0203] Furthermore, for example, base station 100 and mobile station 200 determine that an LTE CRS (e.g., 15kHz SCS) may be placed in at least the 8th symbol within the slot. In this case, base station 100 and mobile station 200 determine, for example, that a DMRS and CRS may collide in the 8th symbol.

[0204] Therefore, the base station 100 and the mobile station 200 determine (in other words, change or shift) the location of the DMRS to a 10th symbol that is different from the 8th symbol. In this case, the determined DMRS placements are the 5th, 10th, and 11th symbols.

[0205] Here, since the interval between DMRS that can be placed in the 10th and 11th symbols is less than or equal to a threshold (1 symbol), the base station 100 and the mobile station 200 may, for example, decide to drop the DMRS that can be placed in the 10th symbol, as shown in Figure 17(b).

[0206] Therefore, as shown in Figure 17(b), base station 100 may transmit DMRS in the 5th and 11th symbols, and mobile station 200 may receive DMRS in the 5th and 11th symbols.

[0207] Alternatively, for example, base station 100 may transmit another signal (e.g., PDSCH) in the 10th symbol where DMRS is dropped, as shown in Figure 17(b).

[0208] For example, as shown in Figure 17(b), when DMRS is placed at the 11th symbol, the channel estimation accuracy is about the same as when DMRS is placed at both the 10th and 11th symbols. In Operation Example 2-2, for example, as shown in Figure 17(b), DMRS is dropped at the 10th symbol, which suppresses the degradation of channel estimation accuracy and the increase in overhead caused by DMRS. In addition, since another signal is placed at the 10th symbol where DMRS has been dropped, resource utilization efficiency can be improved.

[0209] In Figure 17(b), we described the case where the DMRS at the 10th symbol is dropped, among the DMRS that can be placed at the 10th and 11th symbols whose intervals are below the threshold. However, the DMRS that is dropped may also be the DMRS at the 11th symbol.

[0210] The embodiments of this disclosure have been described above.

[0211] (Other embodiments) The embodiments described above assume downlink communication where the base station is the transmitter and the mobile station is the receiver. However, one embodiment of this disclosure is not limited to this and may also be applied to uplink communication where the mobile station is the transmitter and the base station is the receiver, or to communication between mobile stations, i.e., sidelink communication.

[0212] Furthermore, although the above embodiments described the case where the number of symbols in the slot is 14, the number of symbols in the slot is not limited to 14, but may be other numbers (for example, 12 symbols).

[0213] Furthermore, the above embodiments described cases where the position (e.g., symbol) of the DMRS is changed (in other words, shifted). However, the signal whose position is changed is not limited to the DMRS, but may be other signals. Also, the above embodiments described cases where collisions between the DMRS and CRS are avoided by determining the DMRS position. However, the signal that is considered to be colliding with the DMRS is not limited to the CRS, but may be other signals different from the CRS. For example, one embodiment of the present disclosure may be applied to a reference signal, channel, or other signal in NR or LTE instead of at least one of the DMRS and CRS, as follows. • Phase tracking reference signal (PT-RS, PTRS) • Channel State Information Reference Signal (CSI-RS) • Sounding Reference Signal (SRS) • Tracking Reference Signal (TRS) • Discovery Reference Signal (Discovery Signal, DRS) • Primary Synchronization Signal (PSS) Secondary Synchronization Signal (SSS) • Downlink Control Channel (Physical Downlink Control Channel (PDCCH)) • Downlink Shared Channel (Physical Downlink Shared Channel (PDSCH)) • Uplink Control Channel (PUCCH) • Uplink Shared Channel (PUSCH) • Hochi Channel (Physical Broadcast Channel (PBCH)) • Physical Control Format Indicator Channel (PCFICH) • HARQ Indicator Channel (Physical HARQ Indicator Channel (PHICH)) • Multicast Channel (Physical Multicast Channel (PMCH))

[0214] Furthermore, in each of the above embodiments, the PDSCH mapping method is not limited to PDSCH mapping type B. The PDSCH mapping method may be, for example, PDSCH mapping type A, or any other mapping method. One embodiment of this disclosure can be applied, for example, to cases where DMRS and CRS may conflict, regardless of the PDSCH mapping method.

[0215] Furthermore, in each of the above embodiments, when changing (in other words, shifting) the position of the DMRS, it may be changed to a different frequency position. For example, a DMRS belonging to a certain DMRS CDM group may be changed to a frequency position corresponding to a different DMRS CDM group. This allows for more flexible avoidance of collisions with CRS.

[0216] Furthermore, in each of the above embodiments, the "upper layer signal" may also be referred to as, for example, the "RRC signal (RRC signaling)" or the "MAC signal (MAC signaling)".

[0217] Furthermore, in each of the above embodiments, the "reference signal" may also be referred to as, for example, the "reference signal" or "pilot signal." Also, DMRS may be written as "DM-RS."

[0218] Furthermore, in each of the above embodiments, the units of time resources are not limited to slots and symbols, but may also be other time resource units such as frames, subframes, or subslots.

[0219] This disclosure can be implemented as software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be implemented partially or entirely as an integrated circuit (LSI), and each process described in the above embodiments may be controlled partially or entirely by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may be referred to as ICs, system LSIs, super LSIs, or ultra LSIs. The method of integrated circuit implementation is not limited to LSIs, and may also be implemented with dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. This disclosure may be implemented as digital processing or analog processing. Furthermore, if advancements in semiconductor technology or other derived technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, it would be possible to use those technologies to integrate functional blocks. The application of biotechnology, for example, is a possibility.

[0220] This disclosure is applicable to all types of devices, systems, and equipment having communication capabilities (collectively referred to as communication equipment). Communication equipment may include a radio transceiver and a processing / control circuit. A radio transceiver may include a receiver and a transmitter, or both as functions. A radio transceiver (transmitter, receiver) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or similar. Non-exclusive examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, notebooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0221] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting equipment, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0222] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0223] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0224] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0225] A receiving device according to one embodiment of the present disclosure comprises a control circuit that determines the arrangement of a second reference signal based on information that can identify the arrangement of a first reference signal, and a receiving circuit that receives the second reference signal based on the determined arrangement.

[0226] In one embodiment of the present disclosure, the control circuit determines the position of the second reference signal to be a symbol different from the symbol set in the receiving device if the contents shown in the information satisfy certain conditions.

[0227] In one embodiment of the present disclosure, the condition does not depend on whether the symbol on which the first reference signal is located and the symbol set as the second reference signal for the receiving device overlap.

[0228] In one embodiment of the present disclosure, the control circuit, based on the information, determines the position of the second reference signal to be a third symbol different from the second symbol if the first symbol on which the first reference signal is located overlaps with the second symbol set for the receiving device.

[0229] In one embodiment of the present disclosure, the control circuit determines whether the first symbol and the second symbol overlap based on data allocation information including the second reference signal and information regarding the arrangement of the first reference signal.

[0230] In one embodiment of the present disclosure, the control circuit determines the position of the second reference signal to the third symbol if the contents shown in the information satisfy certain conditions.

[0231] In one embodiment of the present disclosure, the condition does not depend on whether the first symbol and the second symbol overlap.

[0232] In one embodiment of the present disclosure, if the control circuit changes the position of at least one of the plurality of second reference signals, it changes the positions of the remaining reference signals based on the position of the at least one reference signal.

[0233] In one embodiment of the present disclosure, the control circuit determines, in the determined arrangement, that one of the two second reference signals whose time interval is less than or equal to a threshold is not transmitted.

[0234] A transmitting device according to one embodiment of the present disclosure comprises a control circuit that determines the arrangement of a second reference signal based on information that can identify the arrangement of a first reference signal, and a transmitting circuit that transmits the second reference signal in the determined arrangement.

[0235] In a receiving method according to one embodiment of the present disclosure, the receiving device determines the arrangement of a second reference signal based on information that can identify the arrangement of a first reference signal, and receives the second reference signal based on the determined arrangement.

[0236] In a transmission method according to one embodiment of the present disclosure, the transmitting device determines the arrangement of a second reference signal based on information that can identify the arrangement of a first reference signal, and transmits the second reference signal in the determined arrangement.

[0237] All disclosures in the specification, drawings, and abstract contained in the Japanese application 2019-149144, filed on August 15, 2019, are incorporated herein by reference. [Industrial applicability]

[0238] One embodiment of this disclosure is useful for a mobile communication system. [Explanation of symbols]

[0239] 100 base stations 101,206 Control Unit 102 Encoding and Modulation Section 103 Signal arrangement section 104 Transmitter 105,201 antennas 200 mobile stations 202 Receiving Unit 203 Signal separation section 204 Channel Estimation Unit 205 Demodulation / Decoding Unit

Claims

1. A control circuit that determines the arrangement of demodulation reference signals (DMRS) in a PDSCH scheduled by PDSCH mapping type B in an NR (New Radio access technology) system, based on the arrangement of cell-specific reference signals (CRS) in an LTE system, A transmitting circuit that transmits the DMRS based on the determined arrangement, It is equipped with, If the duration of the PDSCH scheduled by the PDSCH mapping type B is a specific value, and the subcarrier interval is a specific value, and at least one symbol of the DMRS collides with a symbol of the CRS, then the positions of the at least one symbol of the DMRS and the remaining symbols of the DMRS are shifted back by one symbol. Transmitter.

2. The control circuit, if the content shown in the information satisfies certain conditions, determines the position of the DMRS to a symbol different from the symbol set on the receiving device. The transmitting device according to claim 1.

3. The above condition does not depend on whether the symbols on which the CRS is placed overlap with the symbols set in the DMRS. The transmitting device according to claim 2.

4. The control circuit, when the first symbol on which the CRS is located and the second symbol set for the DMRS overlap, determines the position of the DMRS to be a third symbol different from the second symbol. The transmitting device according to claim 1.

5. The control circuit determines whether the first symbol and the second symbol overlap based on the data allocation method including the DMRS and the arrangement of the CRS. The transmitting device according to claim 4.

6. The control circuit determines the position of the DMRS to the third symbol if the content shown in the information satisfies certain conditions. The transmitting device according to claim 4.

7. The above condition does not depend on whether the first symbol and the second symbol overlap. The transmitting device according to claim 6.

8. If the position of at least one of the plurality of DMRS reference signals is changed, the control circuit changes the positions of the remaining reference signals. The transmitting device according to claim 1.

9. The control circuit determines the position of the DMRS to be a symbol different from the symbol set in the receiving device when the subcarrier interval set in the receiving device is a specific value. The transmitting device according to claim 4.

10. The control circuit determines the position of the DMRS to a symbol different from the symbol set in the receiving device when the subcarrier interval set in the receiving device is 15 kHz. The transmitting device according to claim 4.

11. The control circuit determines the position of the DMRS to be a symbol different from the symbol set in the receiving device when the duration of the PDSCH is a specific value. The transmitting device according to claim 4.

12. The transmitting device is Based on the arrangement of cell-specific reference signals (CRS) in an LTE system, the arrangement of demodulation reference signals (DMRS) in PDSCHs scheduled by PDSCH mapping type B in an NR (New Radio access technology) system is determined. Based on the determined arrangement, the DMRS is transmitted. If the duration of the PDSCH scheduled by PDSCH mapping type B is a specific value, and the subcarrier interval is a specific value, and at least one symbol of the DMRS collides with a symbol of the CRS, then the positions of the at least one symbol of the DMRS and the remaining symbols of the DMRS are shifted back by one symbol. Sending method.

13. If the content shown in the information satisfies certain conditions, the position of the DMRS is determined to be a symbol different from the symbol set in the receiving device. The transmission method according to claim 12.

14. The above condition does not depend on whether the symbols on which the CRS is placed overlap with the symbols set in the DMRS. The transmission method according to claim 13.

15. If the first symbol on which the CRS is placed and the second symbol set for the DMRS overlap, or if certain conditions are met, the position of the DMRS is determined to be a third symbol different from the second symbol. The transmission method according to claim 12.

16. A method for allocating data including the DMRS, and a method for determining whether the first symbol and the second symbol overlap based on the arrangement of the CRS. The transmission method according to claim 15.

17. If the content shown in the information satisfies certain conditions, the location of the DMRS is determined to be the third symbol. The transmission method according to claim 15.

18. The above condition does not depend on whether the first symbol and the second symbol overlap. The transmission method according to claim 17.

19. If the position of at least one of the multiple DMRS reference signals is changed, the positions of the remaining reference signals are changed. The transmission method according to claim 12.

20. When the subcarrier interval set in the receiving device is a specific value, the position of the DMRS is determined to be a symbol different from the symbol set in the receiving device. The transmission method according to claim 15.

21. When the subcarrier interval set in the receiving device is 15 kHz, the position of the DMRS is determined to be a symbol different from the symbol set in the receiving device. The transmission method according to claim 15.

22. When the duration of the PDSCH is a specific value, the position of the DMRS is determined to be a symbol different from the symbol set in the receiving device. The transmission method according to claim 15.

23. A process for determining the arrangement of demodulation reference signals (DMRS) in a PDSCH scheduled by PDSCH mapping type B in an NR (New Radio access technology) system, based on the arrangement of cell-specific reference signals (CRS) in an LTE system, The process of transmitting the DMRS based on the determined arrangement, and the process of controlling If the duration of the PDSCH scheduled by PDSCH mapping type B is a specific value, and the subcarrier interval is a specific value, and at least one symbol of the DMRS collides with a symbol of the CRS, then the positions of the at least one symbol of the DMRS and the remaining symbols of the DMRS are shifted back by one symbol. Integrated circuit.

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