Terminal and base station

Abstract

The present application relates to a terminal and a base station. A user terminal for a future wireless communication system, wherein the wireless communication system bundles multiple time slots (subframes) in the time direction. When bundling is applied, in the first time slot, an additional DMRS (Demodulation Reference Signal) is mapped based on the channel quality (Doppler variation, propagation environment, and other quality degradation reasons), and after the second time slot, the presence or absence of mapping of the additional DMRS or the mapping position is selected based on the rules related to the mapping of the additional DMRS. After the second time slot, the control unit (203) of the user terminal (20) determines the presence or absence of mapping of the additional DMRS and the mapping position based on the above rules.

Description

[0001] This invention is a divisional application of the following patent application: Application number: 201780091863.6, Application date: June 15, 2017, Invention name: User terminal and wireless communication method. Technical Field

[0002] The present invention relates to a user terminal and a wireless communication method in a next generation mobile communication system. Background Art

[0003] In the UMTS (Universal Mobile Telecommunications System) network, Long Term Evolution (LTE) has been standardized for the purpose of achieving higher data rates and lower latency (Non-Patent Document 1). Furthermore, with the goal of further broadening the bandwidth and increasing speed beyond LTE, research is also underway on LTE's successor systems (e.g., LTE-A (LTE-Advanced), FRA (Future Radio Access), 5G (5th generation mobile communication system), 5G+ (5Gplus), and New-RAT (Radio Access Technology)).

[0004] In future wireless communication systems, in order to shorten the processing time required for channel estimation and signal demodulation within a subframe, research is being conducted on mapping the demodulation reference signal (e.g., DMRS (Demodulation Reference Signal)) to the front of the subframe (Front-loaded DMRS) (Non-Patent Document 2).

[0005] Furthermore, in future wireless communication systems, in order to support high-speed movement, studies are underway to map additional DMRS to predetermined symbols within a subframe and correct Doppler fluctuation on the receiving side.

[0006] In addition, future wireless communication systems are studying the bundling of multiple time slots (subframes) in the time direction (time bundling). By aggregating multiple time slots that have been time-bundled and performing channel estimation, it is possible to achieve effects such as improved channel estimation accuracy and improved Doppler resistance.

[0007] Prior art literature

[0008] Non-patent literature

[0009] Non-patent document 1: 3GPP TS 36.300v13.4.0 ", Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 13)," June 2016

[0010] Non-Patent Literature 2: R1-165575, Qualcomm, Ericsson, Panasonic, NTT Docomo, ZTE, Convida, Nokia, ASB, Sony, Intel, “Way Forward On Frame Structure,” May 2016 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] So far, in time bundling, no research has been conducted on the mapping rules of the additional DMRS after the second time slot.

[0013] One object of one embodiment of the present invention is to provide a user terminal and a wireless communication method that can effectively correct Doppler variation by controlling mapping of additional DMRSs after the second time slot when time bundling is applied.

[0014] Means for solving problems

[0015] A user terminal involved in one embodiment of the present invention comprises: a receiving unit, which receives a downlink signal, which is bundled into multiple time slots and includes a control channel, a pre-DMRS (Demodulation Reference Signal) and an additional DMRS; a control unit, which separates the control channel, the pre-DMRS and the additional DMRS from the downlink signal; and a channel estimation unit, which uses the pre-DMRS and the additional DMRS to calculate a channel estimation value, wherein in the first time slot, the additional demodulation reference signal is mapped according to the channel quality, and after the second time slot, the presence or absence of mapping of the additional demodulation reference signal or the mapping position is selected based on a rule related to the mapping of the additional demodulation reference signal, and after the second time slot, the control unit determines the presence or absence of mapping and the mapping position of the additional demodulation reference signal based on the rule.

[0016] A terminal involved in one embodiment of the present invention comprises: a mapping unit for mapping a pre-DMRS (demodulation reference signal) and an additional DMRS (demodulation reference signal) to a PUSCH (physical uplink shared channel); and a sending unit for sending the PUSCH in which multiple time slots are aggregated when a plurality of time slots are aggregated set for the terminal. When the additional DMRS is not mapped to the leading time slot among the multiple time slots aggregated, the mapping unit does not map the additional DMRS in each time slot after the second time slot among the multiple time slots aggregated. When the additional DMRS is mapped to the leading time slot among the multiple time slots aggregated, the mapping unit maps the additional DMRS in each time slot after the second time slot among the multiple time slots aggregated at the same codeword position as the leading time slot.

[0017] Effects of the Invention

[0018] According to one embodiment of the present invention, when time-direction bundling is applied, the mapping of the additional DMRS is controlled in the second time slot and thereafter, thereby making it possible to effectively correct the Doppler variation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A diagram showing an example of the overall configuration of a wireless base station according to an embodiment of the present invention.

[0020] Figure 2 A diagram showing an example of the overall configuration of a user terminal according to an embodiment of the present invention.

[0021] Figure 3 It is a diagram showing a specific example (first mapping rule) of a mapping rule for adding DMRS in one embodiment of the present invention.

[0022] Figure 4 It is a diagram showing a specific example (second mapping rule) of a mapping rule for adding DMRS in one embodiment of the present invention.

[0023] Figure 5 It is a diagram showing a specific example (third mapping rule) of a mapping rule for adding DMRS in one embodiment of the present invention.

[0024] Figure 6 It is a diagram showing a specific example (fourth mapping rule) of a mapping rule for adding DMRS in one embodiment of the present invention.

[0025] Figure 7 It is a diagram showing a specific example (first mapping rule) in which the mapping rule for adding DMRSs in one embodiment of the present invention is applied to mini-slots.

[0026] Figure 8 It is a diagram showing a specific example (third mapping rule) in which the mapping rule for adding DMRSs in one embodiment of the present invention is applied to mini-slots.

[0027] Figure 9 A diagram showing an example of a mapping pattern of a preamble DMRS in a mini-slot (3 symbols).

[0028] Figure 10 It is a diagram showing an example of a mapping pattern of a pre-DMRS in a mini-slot (4 to 14 symbols).

[0029] Figure 11 A diagram showing an example of the hardware configuration of a wireless base station and a user terminal according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0031] (One embodiment)

[0032] The wireless communication system according to this embodiment has at least Figure 1 The wireless base station 10 and Figure 2 The user terminal 20 is shown. The user terminal 20 is connected to the wireless base station 10.

[0033] The wireless base station 10 transmits DL control signals to the user terminal 20 using a downlink control channel (e.g., PDCCH: Physical Downlink Control Channel) and transmits DL data signals and pre-DMRS using a downlink data channel (e.g., PDSCH: Physical Downlink Shared Channel). Furthermore, the user terminal 20 transmits UL control signals to the wireless base station 10 using an uplink control channel (e.g., PUCCH: Physical Uplink Control Channel) or an uplink data channel (e.g., PUSCH: Physical Uplink Shared Channel) and transmits UL data signals and pre-DMRS using an uplink data channel (e.g., PUSCH: Physical Uplink Shared Channel).

[0034] In addition, the downlink channels and uplink channels for transmission and reception between the wireless base station 10 and the user terminal 20 are not limited to the above-mentioned PDCCH, PDSCH, PUCCH, PUSCH, etc., for example, they can also be other channels such as PBCH (Physical Broadcast Channel) and RACH (Random Access Channel).

[0035] In addition, Figure 1 and Figure 2 In the embodiment, the DL / UL signal waveform generated in the wireless base station 10 and the user terminal 20 can be a signal waveform based on OFDM (Orthogonal Frequency Division Multiplexing) modulation, or a signal waveform based on SC-FDMA (Single Carrier-Frequency Division Multiple Access) or DFT-S-OFDM (DFT-Spread-OFDM), or other signal waveforms. Figure 1 and Figure 2 In the present invention, description of the structural parts for generating a signal waveform (for example, a DFT processing part, an IFFT processing part, a CP adding part, a CP removing part, an FFT processing part, an IDFT processing part, etc.) is omitted.

[0036] Furthermore, in the wireless communication system according to the present embodiment, transmission and reception to which time-domain bundling (hereinafter simply referred to as “bundling”) is applied can be performed between the wireless base station 10 and the user terminal 20 .

[0037] <Wireless Base Station>

[0038] Figure 1 It is a diagram showing an example of the overall configuration of the wireless base station 10 according to this embodiment. Figure 1 The wireless base station 10 shown adopts a structure including a scheduler 101, a transmission signal generation unit 102, a coding / modulation unit 103, a mapping unit 104, a transmission unit 105, an antenna 106, a reception unit 107, a control unit 108, a channel estimation unit 109, and a demodulation / decoding unit 110.

[0039] The scheduler 101 schedules downlink signals (DL data signals, DL control signals, and pre-DMRS, etc.) (e.g., resource allocation, antenna port allocation). Furthermore, based on channel quality (due to factors such as Doppler variation and propagation environment), the scheduler 101 selects whether to map additional DMRS to the downlink signals. Furthermore, after the second time slot when downlink bundling is applied, the scheduler 101 selects whether to map additional DMRS and the mapping location. The scheduler 101 then schedules additional DMRS for the downlink based on the selection result.

[0040] In addition, the scheduler 101 schedules UL signals (UL data signals, UL control signals, and pre-DMRS, etc.) (e.g., resource allocation, antenna port allocation). Furthermore, based on channel quality, the scheduler 101 selects whether additional DMRS mapping is required for UL signals. Furthermore, after the second time slot when uplink bundling is applied, the scheduler 101 selects whether additional DMRS mapping is required and the mapping location. The scheduler 101 then schedules additional DMRS for the uplink based on the selection result.

[0041] Note that the mapping rules for the additional DMRS in the second slot and thereafter when bundling is applied will be described in detail later.

[0042] Furthermore, the scheduler 101 outputs scheduling information indicating the scheduling result to the transmission signal generating unit 102 , the mapping unit 104 , and the control unit 108 .

[0043] Furthermore, scheduler 101 sets the MCS (coding rate, modulation scheme, etc.) for the DL data signal and the UL data signal based on, for example, the channel quality between wireless base station 10 and user terminal 20, and outputs the MCS information to transmission signal generation section 102 and coding / modulation section 103. The MCS is not limited to being set by wireless base station 10; it can also be set by user terminal 20. If the MCS is set by user terminal 20, wireless base station 10 only needs to receive the MCS information from user terminal 20 (not shown).

[0044] The transmission signal generation unit 102 generates a transmission signal (including a DL data signal and a DL control signal). For example, the DL control signal includes downlink control information (DCI) including scheduling information (e.g., resource allocation information for DL data signals) or MCS information output from the scheduler 101. The transmission signal generation unit 102 outputs the generated transmission signal to the coding / modulation unit 103.

[0045] The coding / modulation unit 103 performs coding and modulation processing on the transmission signal input from the transmission signal generation unit 102 based on, for example, the MCS information input from the scheduler 101 . The coding / modulation unit 103 outputs the modulated transmission signal to the mapping unit 104 .

[0046] Mapping section 104 maps the transmit signal input from coding / modulation section 103 to a given radio resource (DL resource) based on scheduling information (e.g., DL resource allocation and / or port allocation) input from scheduler 101. Furthermore, mapping section 104 maps reference signals (e.g., pre-DMRS, additional DMRS) to a given radio resource (DL resource) based on the scheduling information. Mapping section 104 outputs the DL signal mapped to the radio resource to transmitting section 105.

[0047] The transmitter 105 performs transmission processing such as up conversion and amplification on the DL signal input from the mapping unit 104 , and transmits the radio frequency signal (DL signal) from the antenna 106 .

[0048] The receiving unit 107 performs reception processing such as amplification and down conversion on the radio frequency signal (UL signal) received by the antenna 106 , and outputs the UL signal to the control unit 108 .

[0049] The control unit 108 separates (demapplies) the UL data signal, the preamble DMRS, and the additional DMRS from the UL signal input from the reception unit 107 based on the scheduling information (UL resource allocation and / or port allocation) input from the scheduler 101. The control unit 108 then outputs the UL data signal to the channel estimation unit 109.

[0050] The channel estimation unit 109 performs channel estimation using the pre-DMRS and the additional DMRS, and outputs a channel estimation value as an estimation result to the demodulation / decoding unit 110 .

[0051] The demodulation / decoding unit 110 demodulates and decodes the UL data signal input from the control unit 108 based on the channel estimation value input from the channel estimation unit 109. The demodulation / decoding unit 110 forwards the demodulated UL data signal to the application unit (not shown). The application unit also performs processing related to layers higher than the physical layer and MAC layer.

[0052] <User Terminal>

[0053] Figure 2 It is a diagram showing an example of the overall configuration of the user terminal 20 according to the present embodiment. Figure 2 The user terminal 20 shown in the figure has a configuration including an antenna 201, a receiving unit 202, a control unit 203, a channel estimation unit 204, a demodulation / decoding unit 205, a transmission signal generation unit 206, a coding / modulation unit 207, a mapping unit 208, and a transmission unit 209. Furthermore, the user terminal 20 performs reception processing on radio frequency signals received at the antenna port assigned to the user terminal 20 itself.

[0054] The receiving unit 202 performs reception processing such as amplification and down-conversion on the RF signal (DL signal) received by the antenna 201, and outputs the DL signal to the control unit 203. The DL signal includes at least a DL data signal, a DL control signal, and a preamble DMRS, and may also include an additional DMRS.

[0055] The control unit 203 separates (demapplies) the DL control signal and the preamble DMRS and additional DMRS from the DL signal input from the receiving unit 202. Furthermore, the control unit 203 determines the presence or absence of additional DMRS mapping and the mapping position for each time slot based on the rules described below. The control unit 203 then outputs the DL control signal to the demodulation / decoding unit 205 and the preamble DMRS and additional DMRS to the channel estimation unit 204.

[0056] Furthermore, the control unit 203 separates (demappes) the DL data signal from the DL signal based on the scheduling information (eg, DL resource allocation information) input from the demodulation / decoding unit 205 , and outputs the DL data signal to the demodulation / decoding unit 205 .

[0057] The channel estimation section 204 performs channel estimation using the separated pre-DMRS and additional DMRS, and outputs a channel estimation value as an estimation result to the demodulation / decoding section 205 .

[0058] The demodulation / decoding unit 205 demodulates the DL control signal input from the control unit 203. Furthermore, the demodulation / decoding unit 205 performs decoding processing (e.g., blind detection) on the demodulated DL control signal. The demodulation / decoding unit 205 outputs the scheduling information (DL / UL resource allocation, pre-DMRS, additional DMRS mapping configuration, etc.) destined for the local device, obtained by decoding the DL control signal, to the control unit 203 and mapping unit 208. Furthermore, the demodulation / decoding unit 205 outputs the MCS information for the UL data signal to the coding / modulation unit 207.

[0059] Furthermore, the demodulation / decoding unit 205 demodulates and decodes the DL data signal input from the control unit 203 based on the channel estimation value input from the control unit 203 and the MCS information for the DL data signal included in the DL control signal. Furthermore, the demodulation / decoding unit 205 forwards the demodulated DL data signal to the application unit (not shown). The application unit also performs processing related to layers higher than the physical layer or MAC layer.

[0060] The transmission signal generating section 206 generates a transmission signal (including a UL data signal or a UL control signal), and outputs the generated transmission signal to the encoding / modulating section 207 .

[0061] The coding / modulation unit 207 performs coding and modulation processing on the transmission signal input from the transmission signal generation unit 206 based on, for example, the MCS information input from the demodulation / decoding unit 205 . The coding / modulation unit 207 outputs the modulated transmission signal to the mapping unit 208 .

[0062] Mapping section 208 maps the transmit signal input from coding / modulation section 207 to a predetermined radio resource (UL resource) based on the scheduling information (UL resource allocation) input from demodulation / decoding section 205. Furthermore, mapping section 208 maps reference signals (e.g., pre-DMRS and additional DMRS) to predetermined radio resources (UL resources) based on the scheduling information (e.g., mapping configuration of pre-DMRS and additional DMRS). Mapping section 208 also selects whether to map the additional DMRS and the mapping position for each slot based on the rules described below.

[0063] The mapping unit 208 outputs the UL signal mapped to the wireless resources to the transmitting unit 209 .

[0064] The transmitting unit 209 performs transmission processing such as up-conversion and amplification on the UL signal (including at least the UL data signal, pre-DMRS, and additional DMRS) input from the mapping unit 208 , and transmits the RF signal (UL signal) from the antenna 201 .

[0065] <Additional DMRS Mapping Rules>

[0066] Next, use Figures 3 to 6 A specific example of the mapping rule for the additional DMRS in the second time slot and thereafter when bundling is applied will be described in detail. In the first time slot, the additional DMRS is mapped based on the channel quality (quality degradation factors such as Doppler variation and propagation environment).

[0067] Figures 3 to 6 3 shows the mapping positions of the control channel, pre-DMRS and additional DMRS in a resource unit (RU) (also called a resource block, a resource block pair, etc.) which is a resource allocation unit.

[0068] The RU has a structure of 168 resource elements (REs), 14 of which are arranged in the time direction and 12 in the frequency direction. One RE is a radio resource area defined by one symbol and one subcarrier. In other words, one RU consists of 14 symbols and 12 subcarriers.

[0069] In the following description, the 14 symbols in the time direction of the RU are referred to as SB1 to SB14 in order from the left, and the 12 subcarriers in the frequency direction of the RU are referred to as SC1 to SC12 in order from the bottom.

[0070] As Figures 3 to 6 The common prerequisite is that the wireless base station 10 (user terminal 20) bundles three time slots, maps the control channel to the two code elements (SB1, SB2) starting from the beginning of each subcarrier in each time slot, maps the pre-DMRS to the third code element (SB3), and in the first time slot, maps the additional DMRS to the ninth code element (SB9).

[0071] [First mapping rule]

[0072] In the first mapping rule, the radio base station 10 (user terminal 20) maps the additional DMRS to the same symbol position as the symbol position to which the additional DMRS is mapped in the first slot in each slot after the second slot of the bundle.

[0073] For example, Figure 3 As shown, the radio base station 10 (user terminal 20) maps the additional DMRS to the 9th symbol (SB9) in the second and third time slots, similarly to the first time slot.

[0074] This eliminates the need for new signaling for notifying the mapping position of the additional DMRS in the second slot and thereafter, thereby reducing overhead.

[0075] In this case, the user terminal 20 (radio base station 10 ) on the receiving side performs channel estimation using the pre-DMRS and the additional DMRS mapped to each time slot.

[0076] In addition, in the first mapping rule, when no additional DMRS is mapped in the first slot, no additional DMRS is mapped in the second and subsequent slots.

[0077] In addition, in the first mapping rule, when the additional DMRS is mapped to the same position as the first slot in the second slot, the insertion position can be shifted backward or forward in the event of a conflict with other reference signals (eg, CSI-RS).

[0078] [Second mapping rule]

[0079] In the second mapping rule, the wireless base station 10 (user terminal 20) always maps the additional DMRS to a predetermined position or a position set by RRC (Radio Resource Control) in each time slot after the second time slot of the bundle.

[0080] For example, it is preset that in the second time slot, the 11th codeword (SB11) is set as the mapping position of the additional DMRS, and in the third time slot, the 9th codeword (SB9) is set as the mapping position of the additional DMRS. Figure 4 As shown, the radio base station 10 (user terminal 20) maps the additional DMRS to the 11th symbol (SB11) of the second slot and the 9th symbol (SB9) of the third slot according to the above setting.

[0081] This eliminates the need for new signaling for notifying the mapping position of the additional DMRS in the second slot and thereafter, thereby reducing overhead.

[0082] In this case, the user terminal 20 (radio base station 10 ) on the receiving side performs channel estimation using the pre-DMRS and the additional DMRS mapped to each time slot.

[0083] In addition, in the second mapping rule, the mapping position of the preset additional DMRS may be different in each time slot or may be common in all time slots.

[0084] In addition, in the second mapping rule, when the additional DMRS is mapped to the second time slot and conflicts with other reference signals (eg, CSI-RS), the insertion position may be shifted backward or forward.

[0085] [Third mapping rule]

[0086] In the third mapping rule, the radio base station 10 (user terminal 20 ) does not map the additional DMRS to the time slots after the second time slot of the bundle.

[0087] For example, Figure 5 As shown, the wireless base station 10 (user terminal 20) does not map the additional DMRS to the second time slot and the third time slot.

[0088] This eliminates the need for new signaling for notifying the mapping position of the additional DMRS in the second slot and thereafter, thereby reducing overhead.

[0089] In this case, the user terminal 20 (radio base station 10) on the receiving side performs channel estimation using the pre-DMRS mapped to each time slot and the additional DMRS mapped to the first time slot.

[0090] [Fourth mapping rule]

[0091] In the fourth mapping rule, the wireless base station 10 appropriately determines whether to map the additional DMRS and the mapping position in each of the bundled second and subsequent time slots. For example, the larger the Doppler variation, the larger the number of time slots to which the additional DMRS is mapped.

[0092] Furthermore, in the fourth mapping rule, the radio base station 10 notifies the user terminal 20 via signaling of the presence or absence of additional DMRS mapping and the mapping location. The user terminal 20 separates and maps the additional DMRS according to the signaled information. The fourth mapping rule enables flexible mapping of the additional DMRS based on factors such as the propagation environment with the user terminal 20, the user terminal's 20 mobility speed, and processing capabilities.

[0093] For example, Figure 6 As shown, the radio base station 10 decides to map the additional DMRS to the 11th symbol (SB11) of the second slot and not to map the additional DMRS to the third slot, and notifies the user terminal 20 of this decision through signaling.

[0094] In this case, the user terminal 20 (radio base station 10) on the receiving side performs channel estimation using the pre-DMRS mapped to each time slot and the additional DMRS mapped to the first and second time slots.

[0095] In addition, in the fourth mapping rule, a setting may be adopted in which the mapping position of the additional DMRS is made different in each time slot, or the mapping position of the additional DMRS may be made common in all time slots.

[0096] Furthermore, in the fourth mapping rule, the wireless base station 10 can notify signaling for each time slot, or it can configure the second time slot and beyond as a common signaling and notify it collectively. Furthermore, the wireless base station 10 can notify signaling for the second time slot and beyond using the same method as the first time slot, or using a different method than the first time slot. For example, the first time slot can be dynamically notified via DCI, while the second time slot can be statically notified via RRC.

[0097] Furthermore, the above-mentioned signaling may be individual signaling for each user terminal 20, or may be common signaling for each allocated RB, each subband, each resource block group (RBG), each component carrier (CC), each cell, or each carrier frequency. Furthermore, the above-mentioned signaling may be any of RRC signaling, MAC signaling, and PHYY signaling. Furthermore, the above-mentioned signaling may be periodically notified or dynamically (aperiodically notified).

[0098] <Effects of this embodiment>

[0099] Thus, in this embodiment, when time bundling is applied, the wireless base station 10 and user terminal 20 control the presence and mapping position of the additional DMRS in each time slot after the second time slot according to the rules related to the mapping of the additional DMRS. This allows for effective correction of Doppler shift when bundling is applied.

[0100] In addition, in this embodiment, the mapping position of the additional DMRS in each time slot after the second time slot is associated with the mapping position of the additional DMRS in the first time slot, or the mapping position of the additional DMRS in each time slot after the second time slot is pre-set. This eliminates the need for new signaling and reduces overhead.

[0101] In addition, in this embodiment, the presence or absence of additional DMRS mapping and the mapping position in each slot after the second slot are appropriately determined and notified through signaling. This allows for flexible additional DMRS mapping according to the propagation environment and the like.

[0102] In addition, in this embodiment, the symbol position of the control channel is not limited to Figures 3 to 6 The symbol positions shown may be mapped to symbols (REs) of only a portion of subcarriers, for example.

[0103] In this embodiment, the applied additional DMRS mapping rule may be notified to the user terminal 20 by signaling from each radio base station 10 or may be described in the specification. Furthermore, the rule described in the specification may be changed by signaling.

[0104] In addition, in this embodiment, a plurality of additional DMRS mapping rules may be combined and applied within the bundled time slot.

[0105] <Mini-slot application example>

[0106] In the above example, the mapping pattern in an RU having 168 REs arranged 14 in the time direction and 12 in the frequency direction is described, but the present invention is not limited to this. For example, the present invention is also applicable to the mapping of pre-DMRS in a resource allocation unit called a mini-slot, where the number of code elements in the mini-slot is any number from 1 to 14.

[0107] [Application Example 1]

[0108] Figure 7 FIG. 2 shows an example of applying the first mapping rule to a mini-slot of 3 symbols. Figure 7 In the example, the wireless base station 10 (user terminal 20) maps the control channel to the first codeword (SB1) in each time slot, maps the pre-DMRS to the second codeword (SB2), and maps the additional DMRS to the third codeword (SB3) in the first time slot.

[0109] In this case, the radio base station 10 (user terminal 20) maps the additional DMRS to the third symbol (SB3) of the second and third time slots.

[0110] The user terminal 20 (radio base station 10) on the receiving side performs channel estimation using the pre-DMRS and additional DMRS mapped to each time slot.

[0111] [Application Example 2]

[0112] Figure 8 FIG. 2 shows an example of applying the third mapping rule to a mini-slot of 5 symbols. Figure 8 In the example, the wireless base station 10 (user terminal 20) maps the control channel to the first codeword (SB1) in each time slot, maps the pre-DMRS to the second codeword (SB2), and maps the additional DMRS to the fifth codeword (SB5) in the first time slot.

[0113] In this case, the radio base station 10 (user terminal 20 ) does not map the additional DMRS to the second and third time slots.

[0114] The user terminal 20 (radio base station 10) on the receiving side performs channel estimation using the pre-DMRS mapped to each time slot and the additional DMRS of the first time slot.

[0115] In addition, in this embodiment, the symbol position of the mini-slot is not limited to Figure 7 、 Figure 8Furthermore, when bundling is applied, mini-slots with different numbers of symbols may also be mixed. In this case, even when the first mapping rule is applied, other mapping rules may be applied to slots with different numbers of symbols than the first slot.

[0116] <Example of Additional DMRS Mapping Pattern in Mini-Slot>

[0117] Next, use Figures 9 and 10 An example of a mapping pattern of additional DMRS in a mini-slot will be described.

[0118] [3-symbol mini-slot]

[0119] Figure 9 An example of the mapping pattern of the additional DMRS in the mini-time slot of 3 code symbols is shown. Figure 9 , the control channel is mapped to the first codeword of all subcarriers.

[0120] Figure 9 (a) shows an example in which the pre-DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the 2nd codeword (SB2), and the additional DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the 3rd codeword (SB3). Figure 9 (b) shows an example in which the pre-DMRS is mapped to the 3rd, 7th, and 11th subcarriers of the 2nd symbol (SB2), and the additional DMRS is mapped to the 3rd, 7th, and 11th subcarriers of the 3rd symbol (SB3). Figure 9 (c) shows an example in which the pre-DMRS is mapped to the 3rd, 4th, 5th, and 6th subcarriers of the 2nd symbol (SB2), and the additional DMRS is mapped to the 3rd, 4th, 5th, and 6th subcarriers of the 3rd symbol (SB3). Figure 9 (d) shows an example in which the pre-DMRS is mapped to the 3rd and 9th subcarriers of the 2nd symbol (SB2), and the additional DMRS is mapped to the 3rd and 9th subcarriers of the 3rd symbol (SB3). Figure 9 (e) shows an example in which the pre-DMRS is mapped to the 6th and 7th subcarriers of the 2nd symbol (SB2), and the additional DMRS is mapped to the 6th and 7th subcarriers of the 3rd symbol (SB3). Figure 9 (f) shows an example in which the preamble DMRS is mapped to the 6th subcarrier of the 2nd symbol (SB2), and the additional DMRS is mapped to the 6th subcarrier of the 3rd symbol (SB3).

[0121] [Mini-slots of 4 to 14 symbols]

[0122] Figure 10An example of the mapping pattern of the additional DMRS in the mini-slot of any number of symbols from 4 to 14 symbols is shown. Figure 10 , the control channel is mapped to the first codeword of all subcarriers.

[0123] Figure 10 (a) shows an example in which the pre-DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the 2nd codeword (SB2), and the additional DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the i-th (i is any integer from 3 to 13) codeword (SBi). Figure 10 (b) shows an example in which the pre-DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the 2nd and 3rd codewords (SB2, SB3), and the additional DMRS is mapped to the 1st, 3rd, 5th, 7th, 9th, and 11th subcarriers of the jth (j is any integer from 4 to 12) and j+1th codewords (SBj, SBj+1). Figure 10 (c) shows an example in which the pre-DMRS is mapped to the 1st, 2nd, 7th, and 8th subcarriers of the 2nd symbol (SB2), and the additional DMRS is mapped to the 1st, 2nd, 7th, and 8th subcarriers of the i-th symbol (SBi). Figure 10 (d) shows an example in which the pre-DMRS is mapped to the 1st, 2nd, 7th, and 8th subcarriers of the 2nd and 3rd symbols (SB2, SB3), and the additional DMRS is mapped to the 1st, 2nd, 7th, and 8th subcarriers of the jth and j+1th symbols (SBj, SBj+1).

[0124] <Other>

[0125] In this embodiment, any of the first to fourth mapping rules for adding DMRSs may be commonly applied to all user terminals 20 within the same cell, or may be appropriately selected for each user terminal 20. Furthermore, a common mapping rule may be applied to all radio base stations 10, or a mapping rule may be appropriately selected for each radio base station 10.

[0126] In addition, in this embodiment, each wireless base station 10 can also select the first to fourth mapping rules of the additional DMRS mentioned above according to the data channel. For example, when each wireless base station 10 maps the additional DMRS of the subframe containing a specific data channel, a predetermined mapping rule can be selected. The so-called specific data channel is, for example, a data channel containing system information (System Information), a data channel containing SRB (Signaling Radio Bearer), a data channel containing a handover command (Hand over command), a data channel scheduled by DCI (Downlink Control Information) sent in the common search space (Common search space), and a data channel containing an activation command (Activation command).

[0127] In addition, in this embodiment, the wireless base station 10 can map the additional DMRS to each layer in a manner that is orthogonal between layers (layer multiplexing), or can map it in a manner that is common to all layers (single-layer transmission). In addition, the wireless base station 10 can set either the antenna port number or the additional DMRS port number to be common, or to be different port numbers.

[0128] In addition, in this embodiment, the additional DMRS may be mapped to m (m is a plurality of) time slots at a rate of 1.

[0129] In addition, the aforementioned pre-DMRS and additional DMRS may also be referred to as demodulation RSs. In addition, the pre-DMRS and additional DMRS may also be referred to as reference signals, etc.

[0130] The embodiments of the present invention have been described above.

[0131] (Hardware Structure)

[0132] In addition, the block diagrams used in the description of the above embodiments show blocks of functional units. These functional blocks (structural parts) are implemented by any combination of hardware and / or software. In addition, the implementation means of each functional block is not particularly limited. That is, each functional block can be implemented by a device that is physically and / or logically coupled, or can be directly and / or indirectly (for example, wired and / or wirelessly) connected to two or more devices that are physically and / or logically separated, and implemented by the above multiple devices.

[0133] For example, a wireless base station, a user terminal, etc. in one embodiment of the present invention may function as a computer that performs processing of the wireless communication method of the present invention. Figure 11This figure shows an example of the hardware configuration of a wireless base station and a user terminal according to one embodiment of the present invention. The wireless base station 10 and the user terminal 20 can be physically configured as a computer device including a processor 1001, memory 1002, storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0134] In the following description, the term "device" can be interpreted as circuit, equipment, unit, etc. The hardware configuration of the wireless base station 10 and the user terminal 20 may include one or more of the devices shown in the figures, or may exclude some of the devices.

[0135] For example, although only one processor 1001 is shown, multiple processors may be present. In addition, a process may be performed by a single processor, or may be performed simultaneously, sequentially, or by other methods by more than one processor. In addition, the processor 1001 may be implemented using more than one chip.

[0136] By reading the given software (program) into hardware such as the processor 1001 and the memory 1002, the processor 1001 performs calculations and controls the communication performed by the communication device 1004, or controls the reading and / or writing of data in the memory 1002 and the storage 1003, thereby realizing various functions in the wireless base station 10 and the user terminal 20.

[0137] Processor 1001 controls the entire computer by, for example, operating an operating system. Processor 1001 may be comprised of a central processing unit (CPU) that includes interfaces with peripheral devices, a control unit, a computing unit, registers, and the like. For example, the aforementioned scheduler 101, control units 108 and 203, transmit signal generation units 102 and 206, encoding / modulation units 103 and 207, mapping units 104 and 208, channel estimation units 109 and 204, and demodulation / decoding units 110 and 205 may also be implemented by processor 1001.

[0138] In addition, the processor 1001 also reads the program (program code), software module or data from the storage 1003 and / or the communication device 1004 into the memory 1002, and performs various processes according to them. As a program, a program that causes the computer to perform at least a part of the operations described in the above embodiment is used. For example, the scheduler 101 of the wireless base station 10 can be implemented by a control program stored in the memory 1002 and operated in the processor 1001, and other functional blocks can be implemented in the same way. Although the above-mentioned various processes are described as being performed by one processor 1001, the above-mentioned various processes can also be performed simultaneously or sequentially by more than two processors 1001. The processor 1001 can be implemented using more than one chip. In addition, the program can also be sent from the network via a telecommunications line.

[0139] Memory 1002 is a computer-readable recording medium and may be composed of, for example, at least one of ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), and RAM (Random Access Memory). Memory 1002 may be referred to as a register, cache, or main memory (main storage device). Memory 1002 can store executable programs (program code), software modules, and the like for implementing the wireless communication method according to an embodiment of the present invention.

[0140] The memory 1003 is a computer-readable recording medium and may be composed of, for example, at least one of an optical disc such as a CD-ROM (Compact Disc ROM), a hard drive, a floppy disk, a magneto-optical disc (e.g., a Compact Disc, a Digital Versatile Disc, a Blu-ray (registered trademark) disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk (registered trademark), a magnetic stripe, and the like. The memory 1003 may also be referred to as an auxiliary storage device. The aforementioned storage medium may be, for example, a database, a server, or other appropriate medium that includes the memory 1002 and / or the memory 1003.

[0141] The communication device 1004 is hardware (a transceiver) used to communicate between computers via a wired and / or wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, etc. For example, the aforementioned transmitters 105 and 209, antennas 106 and 201, and receivers 107 and 202 can also be implemented by the communication device 1004.

[0142] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to the outside (e.g., a display, speaker, LED light, etc.). Alternatively, the input device 1005 and the output device 1006 may be an integrated structure (e.g., a touch panel).

[0143] Furthermore, the processor 1001, the memory 1002, and other devices are connected by a bus 1007 for communicating information. The bus 1007 may be composed of a single bus or may be composed of different buses for different devices.

[0144] Furthermore, the wireless base station 10 and user terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array), and may implement some or all of the functional blocks using this hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0145] (Information notification, signaling)

[0146] In addition, the notification of information is not limited to the form / implementation method described in this specification, and can also be performed through other methods. For example, the notification of information can be implemented through physical layer signaling (for example, DCI (Downlink Control Information: downlink control information), UCI (Uplink Control Information: uplink control information)), high-layer signaling (for example, RRC (Radio Resource Control: radio resource control) signaling, MAC (Medium Access Control: media access control) signaling, broadcast information (MIB (Master Information Block: master information block), SIB (System Information Block: system information block)), other signals or their combination. In addition, RRC signaling can also be referred to as RRC message, for example, it can be RRC Connection Setup message, RRC Connection Reconfiguration message, etc.

[0147] (Adaptive System)

[0148] The various forms / implementations described in this specification can be applied to systems using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, FRA (Future Radio Access), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), other appropriate systems, and / or next-generation systems expanded based on these systems.

[0149] (Processing process, etc.)

[0150] The processing procedures, sequences, flow charts, etc. of the various forms / implementations described in this specification may be reordered as long as there is no contradiction. For example, the elements of the various steps of the method described in this specification are presented in an exemplary order and are not limited to the specific order presented.

[0151] (Base Station Operation)

[0152] In this specification, specific operations performed by a base station (wireless base station) may sometimes be performed by its upper node (upper node) depending on the situation. It should be clear that in a network composed of one or more network nodes (network nodes) having a base station, various operations performed for communication with a terminal may be performed by the base station and / or other network nodes other than the base station (for example, considering MME (Mobility Management Entity: Mobility Management Entity) or S-GW (Serving Gateway: Serving Gateway), etc., but not limited to this). In the above, the case where there is only one other network node other than the base station is illustrated, but it may also be a combination of multiple other network nodes (for example, MME and S-GW).

[0153] (Direction of input and output)

[0154] Information and signals can be output from a higher layer (or lower layer) to a lower layer (or higher layer), or can be input and output via multiple network nodes.

[0155] (Processing of input and output information, etc.)

[0156] Input and output information can be stored in a specific location (e.g., memory) or managed using a management table. Input and output information can be overwritten, updated, or supplemented. Output information can also be deleted. Input information can also be sent to other devices.

[0157] (Judgment method)

[0158] The determination can be made using a value represented by 1 bit (0 or 1), a Boolean value (Boolean: true or false), or a comparison of numerical values (for example, comparison with a given value).

[0159] (software)

[0160] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc.

[0161] Additionally, software, instructions, and the like may be transmitted and received via a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired technologies such as coaxial cable, fiber optic cable, twisted pair, and digital subscriber line (DSL), and / or wireless technologies such as infrared, wireless, and microwave, such wired technologies and / or wireless technologies are included within the definition of transmission medium.

[0162] (information, signal)

[0163] The information, signals, and the like described in this specification may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, and the like referred to in the entire description above may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0164] In addition, the terms described in this specification and / or terms required for understanding this specification may be interpreted as terms with the same or similar meanings. For example, a channel and / or a symbol may also be a signal. In addition, a signal may also be a message. In addition, a component carrier (CC) may also be referred to as a carrier frequency, a cell, etc.

[0165] (“System”, “Network”)

[0166] The terms "system" and "network" used in this specification are used interchangeably.

[0167] (parameters, channel name)

[0168] In addition, the information, parameters, etc. described in this specification can be expressed as absolute values, relative values relative to a given value, or by other corresponding information. For example, wireless resources can be indicated by indexes.

[0169] The names used for the above parameters are not limiting in any way. Moreover, the formulas for using these parameters may sometimes differ from the formulas explicitly disclosed in this specification. Since various channels (e.g., PUCCH, PDCCH, etc.) and information elements (e.g., TPC) can be identified by any appropriate names, the various names assigned to the various channels and information elements are not limiting in any way.

[0170] (Base Station)

[0171] A base station (wireless base station) may include one or more (for example, 3) cells (also called sectors). When a base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, and each smaller area can provide communication services through a base station subsystem (for example, a small base station RRH: Remote Radio Head for indoor use). The term "cell" or "sector" refers to part or all of the coverage area of a base station and / or base station subsystem that provides communication services within the coverage area. Moreover, the terms "base station", "eNB", "gNB", "cell" and "sector" are used interchangeably in this specification. Base stations are sometimes also referred to by terms such as fixed station, NodeB, eNodeB (eNB), gNodeB, access point, micro cell, small cell, etc.

[0172] (terminal)

[0173] A user terminal may be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, a UE (User Equipment) or some other appropriate terminology.

[0174] (Meaning and explanation of terms)

[0175] The terms "determining" and "determining" used in this specification sometimes include a variety of operations. "Judging" and "determining" can, for example, include situations where judging, calculating, computing, processing, deriving, investigating, looking up (for example, searching in a table, database or other data structure), and "ascertaining" are considered to be "judging" and "determining". In addition, "judging" and "determining" can include situations where receiving (for example, receiving information), transmitting (for example, sending information), inputting, outputting, accessing (for example, accessing data in memory) are considered to be "judging" and "determining". In addition, "judging" and "determining" can include situations where resolving, selecting, choosing, establishing, comparing, etc. are considered to be "judging" and "determining". That is, "judging" and "determining" can include situations where any operation is considered to be "judging" and "determining".

[0176] The terms "connected," "coupled," or any variations thereof, mean any connection or coupling, direct or indirect, between two or more elements, and may include situations where one or more intermediate elements are present between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. As used in this specification, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, and, as some non-limiting and non-inclusive examples, using electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, microwave region, and optical (both visible and invisible) region.

[0177] The reference signal can also be referred to as RS (Reference Signal), or as a pilot signal depending on the application standard. In addition, pre-DMRS can also be another corresponding name.

[0178] Unless otherwise specified, the phrase “based on” used in this specification does not mean “based only on.” In other words, the phrase “based on” means both “based only on” and “based at least on.”

[0179] The “portion” in the configuration of each of the above-mentioned devices may be interpreted as a “unit”, a “circuit”, a “device” or the like.

[0180] Whenever used in this specification or claims, the terms "include," "including," and variations thereof are intended to have an inclusive meaning, similar to the term "having." Furthermore, the term "or" as used in this specification or claims is not intended to be an exclusive or.

[0181] A radio frame can be composed of one or more frames in the time domain. In the time domain, one or more individual frames can be referred to as subframes, time units, etc. A subframe can be further composed of one or more time slots in the time domain. A time slot can be further composed of one or more code elements (OFDM (Orthogonal Frequency Division Multiplexing) code elements, SC-FDMA (Single Carrier-Frequency Division Multiple Access) code elements, etc.) in the time domain.

[0182] Radio frame, subframe, time slot, mini-time slot and symbol all represent time units for signal transmission. Radio frame, subframe, time slot, mini-time slot and symbol may also be other corresponding names.

[0183] For example, in the LTE system, a base station performs scheduling to allocate radio resources (frequency bandwidth, transmission power, etc. usable by each mobile station) to each mobile station. The minimum time unit for scheduling can be called a TTI (Transmission Time Interval).

[0184] For example, one subframe may be referred to as a TTI, a plurality of consecutive subframes may be referred to as a TTI, one time slot may be referred to as a TTI, and one mini time slot may be referred to as a TTI.

[0185] A resource unit is a resource allocation unit in the time domain and frequency domain, and may include one or more consecutive subcarriers in the frequency domain. In addition, in the time domain of a resource unit, one or more code elements may be included, and may be the length of a time slot, a mini-time slot, a subframe, or a TTI. A TTI and a subframe may each be composed of one or more resource units. In addition, a resource unit may also be referred to as a resource block (RB), a physical resource block (PRB), a PRB pair, an RB pair, a scheduling unit, a frequency unit, or a subband. In addition, a resource unit may be composed of one or more REs. For example, 1RE is not limited to the name RE as long as it is a resource unit that is smaller than the resource unit that becomes the resource allocation unit.

[0186] The above-mentioned wireless frame structure is merely an example, and the number of subframes contained in the wireless frame, the number of time slots contained in the subframe, the number of mini time slots contained in the subframe, the number of code elements and resource blocks contained in the time slot, and the number of subcarriers contained in the resource block can be changed in various ways.

[0187] Throughout this disclosure, where articles are added by translation, for example, a, an, and the in English, these articles are intended to include the plural unless the context clearly indicates otherwise.

[0188] (Changes in format, etc.)

[0189] Each form / implementation described in this specification may be used individually or in combination, and may be switched between different forms depending on the execution. Furthermore, notification of given information (e.g., notification of "yes X") is not limited to being explicit, but may also be implicit (e.g., not notifying the given information).

[0190] While the present invention has been described in detail above, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented in the form of modifications and variations without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the description in this specification is for illustrative purposes only and is not intended to limit the present invention in any way.

[0191] Industrial applicability

[0192] One embodiment of the present invention is useful in a mobile communication system.

[0193] Description of labels

[0194] 10 Wireless Base Stations

[0195] 20 User Terminals

[0196] 101 Scheduler

[0197] 102, 206 Transmission signal generation unit

[0198] 103, 207 Coding / Modulation Unit

[0199] 104, 208 Mapping Department

[0200] 105, 209 Sending Department

[0201] 106, 201 antennas

[0202] 107, 202 Receiving Department

[0203] 108, 203 Control Department

[0204] 109, 204 Channel Estimation Unit

[0205] 110, 205 demodulation / decoding unit

Claims

1. A terminal comprising: a mapping unit for mapping a pre-demodulation reference signal (DMRS) and an additional demodulation reference signal (DMRS) to a physical uplink shared channel (PUSCH); and a transmitting unit, which transmits the PUSCH in which the plurality of time slots are aggregated, when the aggregation of the plurality of time slots is set for the terminal; In a case where the additional DMRS is not mapped to the first time slot of the plurality of time slots to be aggregated, the mapping unit also does not map the additional DMRS to each time slot after the second time slot of the plurality of time slots to be aggregated, When the additional DMRS is mapped to a leading slot among the aggregated slots, the mapping unit maps the additional DMRS to the same symbol position as that of the leading slot in each slot after the second slot among the aggregated slots.

2. The terminal according to claim 1, The mapping unit maps the pre-DMRS to the same symbol position in the first half of each time slot, The mapping unit maps the additional DMRS to the codeword following the pre-DMRS in each time slot.

3. A terminal comprising: A receiving unit, when aggregation of multiple time slots is set for the terminal, receives a physical downlink shared channel PDSCH in which the multiple time slots are aggregated and which includes a pre-demodulation reference signal (pre-DMRS) and an additional demodulation reference signal (additional DMRS); and The control unit performs reception processing with reference to the pre-DMRS and the additional DMRS, In the case where the additional DMRS is not mapped to the first time slot of the plurality of time slots to be aggregated, the additional DMRS is also not mapped to each time slot after the second time slot of the plurality of time slots to be aggregated, When the additional DMRS is mapped to the leading slot of the aggregated plurality of slots, the additional DMRS is mapped to the same symbol position as the leading slot in each slot after the second slot of the aggregated plurality of slots.

4. The terminal according to claim 3, The pre-DMRS is mapped to the same symbol position in the first half of each time slot, The additional DMRS is mapped to a symbol following the preamble DMRS in each time slot.

5. A base station comprising: a receiving unit configured to receive a physical uplink shared channel (PUSCH) in which the multiple time slots are aggregated and which includes a pre-demodulation reference signal (pre-DMRS) and an additional demodulation reference signal (additional DMRS) when aggregation of multiple time slots is configured for the terminal; and The control unit performs reception processing with reference to the pre-DMRS and the additional DMRS, In a case where the additional DMRS is not mapped to the first time slot of the plurality of time slots to be aggregated, the additional DMRS is also not mapped to each time slot after the second time slot of the plurality of time slots to be aggregated, When the additional DMRS is mapped to the leading slot of the aggregated plurality of slots, the additional DMRS is mapped to the same symbol position as the leading slot in each slot after the second slot of the aggregated plurality of slots.

6. The base station according to claim 5, The pre-DMRS is mapped to the same symbol position in the first half of each time slot, The additional DMRS is mapped to a symbol following the preamble DMRS in each time slot.

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