WO2019138562A1 - Radio communication device - Google Patents

Abstract

Provided is a novel configuration for defining Additional DMRS mapping in a situation where a front-loaded DMRS is mapped to a first symbol of a resource allocation unit of a radio resource. When a downlink radio link signal, in which a front-loaded DMRS (first demodulation reference signal) is mapped to a first symbol of a resource allocation unit, has eight or more symbols in the resource allocation unit and one or more Additional DMRSs (second demodulation reference signals), a base station device maps one Additional DMRS to within three symbols from the last symbol of the resource allocation unit.

Description

Wireless communication device

The present invention relates to a wireless communication device.

In Universal Mobile Telecommunications System (UMTS) networks, Long Term Evolution (LTE) has been specified for the purpose of further high data rates, low delays, etc. (Non-Patent Document 1). Moreover, the successor system of LTE is also considered for the purpose of the further broadbandization and speeding-up from LTE. As successor systems of LTE, for example, LTE-A (LTE-Advanced), FRA (Future Radio Access), 5G (5th generation mobile communication system), 5G + (5G plus), New-RAT (Radio Access Technology), etc. There is something called.

In a future wireless communication system (for example, 5G), a demodulation reference signal for demodulating a data signal is defined, and the specification of mapping of demodulation reference signals to resources is in progress (Refer nonpatent literature 2). Note that the demodulation reference signal may be denoted as “DMRS” (Demodulation Reference Signal), “DM-RS”, or “demodulation RS”.

However, in the 5G specification, additional DMRS (additional DMRS, second demodulation) is performed when DMRS (front-loaded DMRS, first demodulation reference signal) is mapped to the first symbol of the resource allocation unit of the radio resource. The mapping position of the (reference signal) is partially defined.

One aspect of the present invention is to define the mapping of an additional DMRS when the DMRS is mapped to the leading symbol of a resource allocation unit of a radio resource.

A wireless communication apparatus according to the present invention includes a transmitter configured to transmit a downlink radio signal in which a first demodulation reference signal is mapped to a leading symbol of a resource allocation unit, the number of symbols of the resource allocation unit, and the resource allocation unit And a controller configured to control a mapping position of the second demodulation reference signal in the resource allocation unit based on the number of second demodulation reference signals to be mapped in If the number of symbols of the resource allocation unit is 8 or more and the number of the second demodulation reference signals is 1 or more, one of the second symbols within 3 symbols from the last symbol of the resource allocation unit Map the demodulation reference signal for.

According to one aspect of the present invention, a new configuration is provided that defines the mapping of the additional DMRS when the DMRS is mapped to the leading symbol of the resource allocation unit of the radio resource.

It is a block diagram which shows an example of the whole structure of the wireless base station which concerns on one Embodiment. It is a block diagram which shows an example of the whole structure of the user terminal which concerns on one Embodiment. It is a figure explaining mapping type A of DMRS. It is a figure explaining mapping type B of DMRS. It is a figure explaining the mapping position of DMRS in DL. It is a figure showing an example of a mapping position of DMRS in DL-DMRS-add-pos "2" of mapping type B. It is a figure explaining the mapping position of D-DMRS in DL. It is a figure showing an example of a mapping position of DMRS in DL-DMRS-add-pos “1” of mapping type B. It is a figure explaining the mapping position of DMRS in UL. It is a figure showing an example of the mapping position of DMRS in UL-DMRS-add-pos "2" of mapping type B. It is a figure explaining the mapping position of D-DMRS in UL. It is a figure explaining an example of frequency hopping of DMRS of UL. It is a figure explaining the mapping position of DMRS in UL. It is a figure which shows an example of the hardware constitutions of the wireless base station 10 which concerns on one embodiment of this invention, and the user terminal 20. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(One embodiment)
The wireless communication system according to the present embodiment includes the wireless base station 10 shown in FIG. 1 and the user terminal 20 shown in FIG. The radio base station 10 is also called, for example, an eNB (eNodeB) or a gNB (gNodeB). The user terminal 20 is also called, for example, a UE (User Equipment). The user terminal 20 is wirelessly connected (wireless access) to the wireless base station 10.

The radio base station 10 transmits a downlink (DL: Downlink) control signal to the user terminal 20 using a downlink control channel (for example, PDCCH: Physical Downlink Control Channel). The radio base station 10 transmits a DL data signal and DMRS to the user terminal 20 using a downlink data channel (for example, downlink shared channel: PDSCH: Physical Downlink Shared Channel).

In addition, the user terminal 20 performs uplink with the radio base station 10 using an uplink control channel (for example, PUCCH: Physical Uplink Control Channel) or an uplink data channel (for example, uplink shared channel: PUSCH: Physical Uplink Shared Channel). Transmit a link (UL: Uplink) control signal. The user terminal 20 transmits a UL data signal and a DMRS to the radio base station 10 using an uplink data channel (for example, uplink shared channel: PUSCH: Physical Uplink Shared Channel).

In the radio communication system in the present embodiment, although described later, one of two mapping types (mapping type A and mapping type B) is set in the mapping of DMRS. Then, in the wireless communication system in the present embodiment, in each of the two mapping types, some positions of DMRS are defined, and one of them is set.

In addition, the downlink channel and uplink channel which the wireless base station 10 and the user terminal 20 transmit and receive are not limited to said PDCCH, PDSCH, PUCCH, PUSCH etc. The downlink channel and uplink channel transmitted and received by the radio base station 10 and the user terminal 20 may be, for example, another channel such as PBCH (Physical Broadcast Channel) or RACH (Random Access Channel).

Further, in FIG. 1 and FIG. 2, the DL and / or UL signal waveforms generated in the radio base station 10 and the user terminal 20 may be signal waveforms based on orthogonal frequency division multiplexing (OFDM) modulation. Alternatively, the DL and / or UL signal waveforms may be signal waveforms based on SC-FDMA (Single Carrier-Frequency Division Multiple Access) or DFT-S-OFDM (DFT-Spread-OFDM). Alternatively, the DL and / or UL signal waveforms may be other signal waveforms. In FIG. 1 and FIG. 2, the description of components (for example, an IFFT processing unit, a CP adding unit, a CP removing unit, an FFT processing unit, etc.) for generating a signal waveform is omitted.

<Wireless base station>
FIG. 1 is a block diagram showing an example of the entire configuration of the radio base station 10 according to the present embodiment. The radio base station 10 includes a scheduler 101, a transmission signal generation unit 102, an encoding / modulation unit 103, a mapping unit 104, a transmission unit 105, an antenna 106, a reception unit 107, a control unit 108, and a channel. An estimation unit 109 and a demodulation / decoding unit 110 are included. Note that the radio base station 10 may have a configuration of MU-MIMO (Multi-User Multiple-Input Multiple-Output) in which communication is simultaneously performed with a plurality of user terminals 20. Alternatively, the radio base station 10 may have a configuration of Single-User Multiple-Input Multiple-Output (SU-MIMO) that communicates with one user terminal 20. Alternatively, the radio base station 10 may have both SU-MIMO and MU-MIMO configurations.

The scheduler 101 performs scheduling (for example, resource allocation and port allocation) of DL signals (DL data signal, DL control signal, DMRS, etc.). The scheduler 101 also performs scheduling (for example, resource allocation and port allocation) of UL signals (UL data signal, UL control signal, DMRS, etc.).

The scheduler 101 also sets the DMRS mapping type in the DL signal and the UL signal. Mapping types include mapping type A and mapping time B, which will be described later. The scheduler 101 maps the DMRS to predetermined symbols determined in each mapping type.

The information related to the above DMRS mapping may be described as setting information. The setting information may include other information. The setting information may be included in, for example, downlink control information (DCI).

The scheduler 101 outputs scheduling information including setting information to the transmission signal generation unit 102 and the mapping unit 104. The scheduler 101 may be regarded as an example of a control unit that controls the position at which the DMRS is mapped to the DL signal, as described later.

Also, the scheduler 101 may perform, for example, MCS (Modulation and Coding Scheme) (coding rate, modulation scheme, etc.) of the DL data signal and the UL data signal based on the channel quality between the radio base station 10 and the user terminal 20. Set The scheduler 101 outputs the information on the set MCS to the transmission signal generation unit 102 and the coding / modulation unit 103. In addition, MCS is not limited when the wireless base station 10 sets, and the user terminal 20 may set it. When the user terminal 20 sets an MCS, the radio base station 10 may receive MCS information from the user terminal 20 (not shown).

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 DCI including scheduling information (for example, setting information) output from the scheduler 101 or MCS information. The transmission signal generation unit 102 outputs the generated transmission signal to the coding / modulation unit 103.

The encoding / modulation unit 103 performs encoding processing 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. Encoding / modulation section 103 outputs the modulated transmission signal to mapping section 104.

Based on the scheduling information (for example, DL resource allocation and setting information) input from scheduler 101, mapping section 104 transmits a predetermined radio resource (DL resource) from transmission signal input from encoding / modulation section 103. Map to). Also, the mapping unit 104 maps the DMRS to a predetermined 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.

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

The reception 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.

The control unit 108 separates (demaps) the UL data signal and the DMRS from the UL signal input from the receiving unit 107 based on the scheduling information (UL resource allocation) input from the scheduler 101. Then, control section 108 outputs the UL data signal to demodulation / decoding section 110 and outputs DMRS to channel estimation section 109.

Channel estimation section 109 performs channel estimation using the DMRS of the UL signal, and outputs a channel estimation value that is the estimation result to demodulation and decoding section 110.

Demodulation / decoding section 110 performs demodulation and decoding processing on the UL data signal input from control section 108 based on the channel estimation value input from channel estimation section 109. The demodulation / decoding unit 110 transfers the UL data signal after demodulation to an application unit (not shown). The application unit performs processing on a layer higher than the physical layer or the MAC layer.

The block including the scheduler 101, the transmission signal generation unit 102, the encoding / modulation unit 103, the mapping unit 104, and the transmission unit 105 may be regarded as an example of a wireless transmission apparatus provided in the wireless base station 10. Also, the block including the receiving unit 107, the control unit 108, the channel estimation unit 109, and the demodulation / decoding unit 110 may be considered as an example of a wireless reception apparatus provided in the wireless base station 10.

In addition, as described later, the block including the control unit 108, the channel estimation unit 109, and the demodulation / decoding unit 110 is a processing unit that receives and processes a UL signal using DMRS mapped in the time domain of the UL signal. You can think of it as an example of

<User terminal>
FIG. 2 is a block diagram showing an example of the entire configuration of the user terminal 20 according to the present embodiment. The user terminal 20 includes an antenna 201, a reception unit 202, a control unit 203, a channel estimation unit 204, a demodulation / decoding unit 205, a transmission signal generation unit 206, an encoding / modulation unit 207, and a mapping unit 208. And the transmission unit 209.

The reception unit 202 performs reception processing such as amplification and down conversion on the radio frequency 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 and DMRS.

The control unit 203 separates (demaps) the DL control signal and the DMRS from the DL signal input from the receiving unit 202. Then, the control unit 203 outputs the DL control signal to the demodulation / decoding unit 205, and outputs the DMRS to the channel estimation unit 204. The control unit 203 can separate DMRSs based on the setting information of the DMRSs.

Channel estimation section 204 performs channel estimation using the separated DMRS, and outputs a channel estimation value that is the estimation result to demodulation and decoding section 205.

The demodulation / decoding unit 205 demodulates the DL control signal input from the control unit 203. Further, the demodulation / decoding unit 205 performs a decoding process (for example, a blind detection process) on the DL control signal after demodulation. Demodulation / decoding section 205 outputs scheduling information (for example, DL / UL resource allocation) addressed to the own apparatus obtained by decoding the DL control signal to control section 203 and mapping section 208, for the UL data signal. The MCS information is output to the encoding / modulation unit 207.

Further, demodulation / decoding section 205 uses the channel estimation value input from channel estimation section 204 based on the MCS information for the DL data signal contained in the DL control signal input from control section 203, and uses control channel 203 from control section 203. Demodulation and decoding are performed on the input DL data signal. Also, the demodulation / decoding unit 205 transfers the demodulated DL data signal to an application unit (not shown). The application unit performs processing on a layer higher than the physical layer or the MAC layer.

The transmission signal generation unit 206 generates a transmission signal (including a UL data signal or a UL control signal), and outputs the generated transmission signal to the encoding / modulation unit 207.

The encoding / modulation unit 207 performs encoding processing 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. Coding / modulation section 207 outputs the modulated transmission signal to mapping section 208.

The mapping unit 208 maps the transmission signal input from the coding / modulation unit 207 to a predetermined radio resource (UL resource) based on the scheduling information (UL resource allocation) input from the demodulation / decoding unit 205. . Also, the mapping unit 208 maps the DMRS to a predetermined radio resource (UL resource) based on the scheduling information.

The mapping of the DMRS to the radio resource may be controlled by, for example, the control unit 203. For example, as described later, the control unit 203 may regard the position at which the DMRS is mapped to the UL signal as an example of a control unit that hops to different frequencies at different times.

The transmitting unit 209 performs transmission processing such as up-conversion and amplification on the UL signal (including at least the UL data signal and the DMRS) input from the mapping unit 208, and transmits a radio frequency signal (UL signal) from the antenna 201. Send.

The block including the transmission signal generation unit 206, the encoding / modulation unit 207, the mapping unit 208, and the transmission unit 209 may be considered as an example of a wireless transmission apparatus provided in the user terminal 20. Also, the block including the reception unit 202, the control unit 203, the channel estimation unit 204, and the demodulation / decoding unit 205 may be considered as an example of a wireless reception apparatus provided in the user terminal 20.

In addition, as described later, the block including the control unit 203, the channel estimation unit 204, and the demodulation / decoding unit 205 is a processing unit that receives and processes a DL signal using DMRS mapped in the time domain of the DL signal. You can think of it as an example of

In the wireless communication system including the wireless base station 10 and the user terminal 20 described above, a front-loaded DMRS is used as an example of the DMRS. The front-loaded DMRSs are mapped forward in the time direction in slots, which are resource allocation units (or may be referred to as resource units and subframes, etc.). In other words, the first DMRS in the time direction mapped to the slots is called front-loaded DMRS. The forward mapping of the DMRS can reduce the processing time required for channel estimation and demodulation processing in the wireless communication system. Hereinafter, front-loaded DMRS may be described as FL-DMRS, front-load DMRS, or a first demodulation reference signal.

The mapping type of DMRS is divided into mapping type A and mapping type B according to the mapping position of FL-DMRS. Hereinafter, two mapping types A and B will be described.

<Mapping type A>
FIG. 3A is a diagram for explaining mapping type A of DMRS. The slot shown in FIG. 3A has, for example, a configuration in which 168 resource elements (RE: Resource Element) are aligned in the time direction and 14 in the frequency direction. One RE is a radio resource area defined by one symbol and one subcarrier. One slot consists of 14 symbols and 12 subcarriers.

In the following description, 14 symbols in the time direction of RU are referred to as SB0 to SB13 in order from the left. Also, 12 subcarriers in the frequency direction of RU are called SC0 to SC11 in order from the bottom. The definition of slot is not limited to the above. For example, the number of symbols in a slot may be less than fourteen. Also, for example, the number of subcarriers in the slot may be less than 11 and may be 13 or more.

The PDCCH is mapped to two symbols SB0 and SB1 at the head of the slot. Alternatively, the PDCCH is mapped to three symbols SB0, SB1, and SB2 at the head of the slot. In the example of FIG. 3A, the PDCCH is mapped to two symbols SB0 and SB1 at the head of the slot. The mapping of PUCCH in the UL signal may be the same as PDCCH.

In mapping type A, the FL-DMRS is mapped to the third symbol (SB2) or the fourth symbol (SB3) of the slot. That is, FL-DMRSs are mapped after PDCCH symbols in the time direction.

For example, when the PDCCH is mapped to two symbols SB0 and SB1 as shown in FIG. 3A, the FL-DMRS is mapped to SB2. Also, when the PDCCH is mapped to three symbols SB0, SB1 and SB2, the FL-DMRS is mapped to SB3.

An additional DMRS (additional DMRS) may be mapped behind the time direction of the FL-DMRS. In the example of FIG. 3A, the additional DMRS is mapped to SB11. The additional DMRS can, for example, suppress DMRS degradation based on high doppler, or extend the DMRS coverage. Hereinafter, the additional DMRS may be described as an A-DMRS or a second demodulation reference signal.

<Mapping type B>
FIG. 3B is a diagram for explaining mapping type B of DMRS. As described above, in the DMRS mapping type A, the FL-DMRS is mapped to the third symbol (SB2) or the fourth symbol (SB3) of the slot. On the other hand, in DMRS mapping type B, FL-DMRS is mapped to the leading symbol of the slot. That is, as shown in FIG. 3B, FL-DMRS is mapped to SB0.

In addition, in FIG. 3B, PDCCH or PUCCH is not mapped to the slot. If the FL-DMRS is mapped to the leading symbol of the slot, the PDCCH or PUCCH is mapped to another slot. Further, in the example of FIG. 3B, A-DMRS is mapped to SB12.

Although FIG. 3A and FIG. 3B illustrate the case where the number of symbols of A-DMRS is one, in this embodiment, the number of symbols of A-DMRS is not limited to one, and a plurality of symbols are also used. is there. Moreover, although the case where DMRS is mapped to a continuous subcarrier is illustrated in FIG. 3A and 3B, DMRS may be mapped discontinuously to a subcarrier in this Embodiment.

In each of DL and UL, mapping positions of DMRS are defined. Hereinafter, the mapping position of DMRS including A-DMRS will be described.

<Mapping position of DMRS in DL>
FIG. 4 is a diagram for explaining the mapping position of DMRS in the DL. “Duration of PDSCH transmission” illustrated in FIG. 4 indicates the number of symbols constituting PDCCH and PDSCH in mapping type A. Also, “Duration of PDSCH transmission” indicates the number of symbols constituting PDSCH in mapping type B. In NR (New Radio), the number of symbols constituting PDSCH is variable. For example, the number of symbols constituting the PDCCH may be any of 1 to 3.

The mapping position of DMRS in DL is divided into two types, mapping type A and mapping type B, as shown in “PDSCH mapping type A” and “PDSCH mapping type B” in FIG. 4. Then, as shown in “DL-DMRS-add-pos” in FIG. 4, in each mapping type, the position of A-DMRS in each of four cases “0, 1, 2, 3” is defined.

“0, 1, 2, 3” shown in the lower column of “DL-DMRS-add-pos” indicates the number of symbols of A-DMRS mapped to PDSCH. For example, “0” indicates that A-DMRS is not mapped to PDSCH. “1” indicates that the number of symbols of A-DMRS mapped to PDSCH is one. In other words, FL-DMRS and one symbol A-DMRS are mapped to PDSCH. “2” indicates that the number of A-DMRS symbols mapped to PDSCH is two. In other words, in the PDSCH, the FL-DMRS and the two-symbol A-DMRS are mapped. “3” indicates that the number of A-DMRS symbols mapped to PDSCH is three. In other words, FL-DMRS and 3-symbol A-DMRS are mapped to PDSCH.

“L ₀ ” and the numbers shown in the bold frame A1 of FIG. 4 indicate the positions of symbols to which the DMRS is mapped. Mapping type A “l ₀ ” takes one of the values “2” and “3”. Mapping type B “l ₀ ” takes a value of “0”. That is, “l ₀ ” indicates the symbol position to which the FL-DMRS is mapped (see FL-DMRS in FIGS. 3A and 3B). The numbers shown in the bold frame A1 in FIG. 4 indicate the positions of symbols to which A-DMRSs are mapped.

The position of the DMRS of each mapping type is defined by the number of symbols constituting the PDSCH. For example, (if the Duration of PDSCH Transmission shown in Fig. 4 of "11") number of symbols constituting the PDSCH is the case of "11", the mapping type A, the symbols of _{"l 0",} the _"l 0, 9" The symbol is mapped to one of the symbols “l ₀ , 6, 9”. Further, for example, (if the Duration of PDSCH Transmission shown in Fig. 4 of "12") when the number of symbols constituting the PDSCH is "12", the mapping type B, a symbol of _{"l 0", "l} 0, 10 The symbol is mapped to one of the symbols of “ ₀ , 5, 10” and “1 ₀ , 3, 6, 9”.

In mapping type A, when the number of symbols constituting PDSCH is eight or less, A-DMRS is not mapped to PDSCH. In mapping type B, when the number of symbols constituting PDSCH is 6 or less, A-DMRSs are not mapped to PDSCH.

The position of the DMRS in the DL is notified from the radio base station 10 to the user terminal 20 by, for example, DCI. For example, the radio base station 10 stores the information of the table shown in FIG. 4 in the memory as a table, for example. The radio base station 10 refers to the table stored in the memory, and specifies the DMRS mapping type and any value of “0 to 3” of DL-DMRS-add-pos shown in FIG.

The user terminal 20 stores the information of the table shown in FIG. 4 in the memory as a table, for example. The user terminal 20 refers to the memory table based on the DMRS mapping type specified from the radio base station 10 and any value of “0 to 3” of the DL-DMRS-add-pos, Determine the position of the symbol to which is mapped.

For example, it is assumed that the radio base station 10 configures PDSCH with 12 symbols and maps DMRS to the position indicated by DL-DMRS-add-pos “2” of mapping type B (dotted line frame A2 in FIG. 4). reference).

FIG. 5 is a diagram showing an example of the mapping position of the DMRS in the DL-DMRS-add-pos “2” of the mapping type B. It is assumed that the radio base station 10 configures the PDSCH with 12 symbols (SB0 to SB11), and maps the DMRS at the position indicated by the DL-DMRS-add-pos “2” of the mapping type B (dotted line in FIG. 4). See frame A2). In this case, FL-DMRS is mapped to SB0 and A-DMRS is mapped to SB5 and SB10 as shown in FIG. 5, for example.

As described above, the radio base station 10 notifies the user terminal 20 of the mapping position of the DMRS in the DL, for example, using the DCI. In the case of the above example, the radio base station 10 includes information of DL-DMRS-add-pos “2” of mapping type B in the DCI, and notifies the user terminal 20 of the information.

The user terminal 20 refers to the table stored in the memory (the information in the table shown in FIG. 4) based on the information of the DL-DMRS-add-pos “2” of the mapping type B included in the DCI. . Then, the user terminal 20, FD-DMRS to _{l 0-th} symbol (SB0) is mapped, determining that A-DMRS is mapped to and SB5 and SB 10. The user terminal 20 can determine the number of symbols (12 symbols) constituting the PDSCH based on the scheduling information notified from the radio base station 10.

In the 5G specification, the mapping position of the DMRS in the frame A3 of the dashed dotted line of the mapping type B shown in FIG. 4 is not defined. So, in this invention, the mapping position of DMRS in frame A3 of the dashed dotted line of mapping type B was specified.

The DMRSs within the dashed dotted line frame A3 shown in FIG. 4 are defined so that the symbol intervals to be mapped are equal intervals or close to equal intervals, and are mapped to symbols determined to some extent. For example, when DL-DMRS-add-pos is “2”, when Duration of PDSCH transmission is “2 n” and “2 n + 1” (n is any of 4, 5 and 6), The positions from the beginning of the A-DMRS slot are the same.

Also, in the time direction, the last DMRS is defined to be mapped within the last 3 symbols of the symbols making up the PDSCH. In other words, DMRS is defined to be mapped to both ends of PDSCH (one end is FL-DMRS and is mapped to the leading symbol) in the time direction.

For example, as shown in FIG. 5, DMRSs are mapped to PDSCHs at five symbol intervals. Further, as shown in FIG. 4, the DMRS is mapped (reused) to symbols determined as SB3 to SB6, SB8 to SB10, and SB12. Further, as shown in FIG. 5, in the time direction, the last DMRS (A-DMRS) is mapped to SB10 in the last three symbols SB9, SB10 and SB11 of 12 symbols constituting the PDSCH.

In this way, by defining the DMRS mapping intervals to be equal intervals or close to equal intervals, it is possible to equalize the channel estimation accuracy in the PDSCH. Also, by mapping the DMRS to a certain fixed symbol, the collision between the DMRS and the data signal is avoided, and the probability of the collision between the DMRSs is increased, and the DMRS and the data signal collide, compared to the DMRS. It is possible to improve on average the performance of channel estimation when the two collide with each other. Also, by mapping the last DMRS in the last 3 symbols of the symbols constituting the PDSCH in the time direction, it is possible to improve the interpolation accuracy of channel estimation over the PDSCH.

<Mapping position of D-DMRS (Double-symbol DMRS) in DL>
Next, the mapping position of the double symbol DMRS (Double-symbol DMRS; hereinafter may be described as D-DMRS) will be described.

In D-DMRS in DL, DMRSs are mapped two consecutive symbols. For example, in mapping type A, FL-DMRS is mapped to two symbols of the third and fourth and (SB2, SB3) consecutively, or two of the fourth and fifth and (SB3, SB4) It is mapped continuously to the symbol. Also, A-DMRSs are mapped to two symbols in succession.

Similarly to mapping type A, FL-DMRS is mapped to two symbols of first, second and (SB0, SB1) in succession. Also, A-DMRSs are mapped to two symbols in succession.

FIG. 6 is a diagram for explaining the mapping position of D-DMRS in the DL. The view of the table shown in FIG. 6 is the same as that of FIG. However, the DMRS is mapped to a symbol indicated by “l ₀ ” and a number shown in the bold line frame A11, and a symbol (continuous in the time direction) following the symbol.

For example, assume that the mapping type of D-DMRS is mapping type B, and PDCSH consists of 12 symbols. Also, it is assumed that DL-DMRS-add-pos is “1”. In this case, FL-DMRS is mapped to SB0 and SB1, and A-DMRS is mapped to SB9 and SB10 (see dotted frame A12 in FIG. 6).

FIG. 7 is a diagram showing an example of the mapping position of the DMRS in the DL-DMRS-add-pos “1” of the mapping type B. It is assumed that the radio base station 10 configures the PDSCH with 12 symbols (SB0 to SB11), and maps the DMRS at the position indicated by the DL-DMRS-add-pos “1” of the mapping type B (dotted line in FIG. 6). See frame A12). In this case, FL-DMRS is mapped to SB0 and SB1, and A-DMRS is mapped to SB9 and SB10, as shown in FIG. 7, for example.

Also in the D-DMRS, the mapping position of the DMRS is notified from the radio base station 10 to the user terminal 20 as in the single DMRS. The user terminal 20 stores the information of the table shown in FIG. 6 in the memory as a table, for example. The user terminal 20 refers to the memory table based on the DMRS mapping type designated from the radio base station 10 and any value of “0, 1” of DL-DMRS-add-pos, and D -Determine (acquire) the position of the symbol to which DMRS is mapped.

In the specification of 5G, the mapping position of the DMRS in the frame A13 of the dashed dotted line of the mapping type B shown in FIG. 6 is not defined. So, in this invention, the mapping position of DMRS in frame A13 of the dashed dotted line of mapping type B was specified.

The DMRSs within the dashed-dotted line frame A13 shown in FIG. 6 are defined to be mapped to symbols determined to some extent. Also, in the time direction, the last DMRS is defined to be mapped within the last 3 symbols of the symbols making up the PDSCH. Also, when DL-DMRS-add-pos is “0, 1” or “2”, the position from the beginning of the A-DMRS slot where the Duration of PDSCH transmission is “10” or more is mapping type A And the mapping type B are identical.

For example, as shown in FIG. 6, two SBs 9 are reused in DMRS mapping. Further, as shown in FIG. 7, in the time direction, the last DMRS (A-DMRS) is mapped to SB10 in the last three symbols SB9, SB10 and SB11 of the 12 symbols constituting the PDSCH.

Thus, by mapping the DMRS to a certain fixed symbol, the performance of channel estimation when DMRSs collide can be improved on average compared to when DMRSs collide with data. Also, by mapping the last DMRS in the last three symbols of the symbols that make up the PDSCH in the time direction, it is possible to improve the interpolation accuracy of channel estimation over the PDSCH.

As shown in FIG. 6, one D-DMRS A-DMRS is defined. That is, in A-DMRS of D-DMRS, DL-DMRS-add-pos defines “0, 1” and does not define 2 or more. The reason why two or more A-DMRSs of D-DMRS are not defined is to suppress the reduction of PDSCH resources by DMRS.

For example, as shown in FIG. 7, when there is one A-DMRS of D-DMRS, the number of symbols to which DMRS is mapped is four, that is, SB0, SB1, SB9, and SB10. Assuming that the number of A-DMRSs of D-DMRSs is two, the number of symbols to which DMRSs are mapped is six, and thus the resources of PDSCH for mapping data signals are reduced. Therefore, A-DMRS of D-DMRS is not specified to 2 or more.

<Mapping position of DMRS in UL>
Next, the mapping position of DMRS in UL will be described.

FIG. 8 is a diagram for explaining the mapping position of DMRS in UL. The view of the table shown in FIG. 8 is the same as that of FIG. However, “PUSCH duration in symbols” shown in FIG. 8 indicates the number of symbols constituting PUCCH and PUSCH when the mapping type is A. Also, “PUSCH duration in symbols” indicates the number of symbols constituting the PUSCH when the mapping type is B. In NR (New Radio), the number of symbols constituting PUSCH is variable. For example, the number of symbols constituting the PUCCH may be any of 1 to 3.

The position of the DMRS in the UL is notified from the radio base station 10 to the user terminal 20, for example, by DCI. The user terminal 20 stores the information of the table shown in FIG. 8 in the memory as a table, for example. The user terminal 20 refers to the memory table based on the information on the mapping position of the DMRS notified by the DCI, and determines the position of the DMRS symbol to be mapped to the PUSCH.

For example, it is assumed that the user terminal 20 is notified from the radio base station 10 that the PUSCH is composed of 12 symbols and that the DMRS is mapped to the position indicated by the DL-DMRS-add-pos “2” of the mapping type B. (See the dotted frame A21 in FIG. 8).

FIG. 9 is a diagram showing an example of the mapping position of DMRS in UL-DMRS-add-pos “2” of mapping type B. As described above, the user terminal 20 may configure the PUSCH with 12 symbols from the radio base station 10 and map the DMRS to the position indicated by the DL-DMRS-add-pos “2” of the mapping type B. Suppose that you were notified. In this case, FL-DMRS is mapped to SB0 and A-DMRS is mapped to SB5 and SB10, as shown in FIG. 9, for example. Since the radio base station 10 sets the DMRS mapping position in UL and notifies the set information to the user terminal 20, it can determine which symbol of the PUSCH received from the user terminal 20 the DMRS is mapped to .

In addition, the user terminal 20 may determine the mapping position of DMRS in UL. For example, the user terminal 20 may map the DMRS of UL to the determined mapping position, and may notify the wireless base station 10 of the information of the determined mapping position, for example, included in UCI (Uplink Control Information). The radio base station 10 stores the information of the table shown in FIG. 8 in a memory as a table, for example. The radio base station 10 refers to the table of the memory based on the information on the mapping position of the DMRS notified by the UCI, and determines the position of the DMRS symbol mapped to the PUSCH.

In the 5G specification, the mapping position of the DMRS in the frame A22 of the dashed dotted line of the mapping type B shown in FIG. 8 is not defined. So, in this invention, the mapping position of DMRS in frame A22 of the dashed dotted line of mapping type B was specified.

It is defined that the DMRS in the dashed dotted line frame A22 shown in FIG. 8 is to be mapped to symbols to which the symbol intervals to be mapped are equidistant or near equidistant and to a certain degree. Also, in the time direction, it is defined that the last DMRS is mapped within the last 5 symbols of the symbols making up the PUSCH. In other words, DMRS is defined to be mapped to both ends of PUSCH (one end is FL-DMRS and is mapped to the leading symbol) in the time direction.

Thus, by defining the DMRS mapping intervals to be equal intervals or close to equal intervals, it is possible to equalize the accuracy of channel estimation in the PUSCH. Also, by mapping DMRSs to symbols determined to some extent, it is possible to improve the performance of channel estimation when DMRSs collide. Also, by mapping the last DMRS in the last 5 symbols of the symbols making up the PUSCH in the temporal direction, it is possible to improve the interpolation accuracy of channel estimation over the PDSCH.

<Mapping position of D-DMRS in UL>
Next, the mapping position of D-DMRS will be described.

D-DMRSs in UL are mapped to DMRSs in two consecutive symbols, similarly to DMRSs in DL. For example, in the PDSCH, DMRSs are mapped two consecutive symbols in the same manner as the DMRSs shown in FIG.

FIG. 10 is a diagram for explaining the mapping position of D-DMRS in UL. The view of the table shown in FIG. 10 is the same as that of FIG. However, the DMRS is mapped to a symbol indicated by "l ₀ " and a number shown in the bold line frame A31, and a symbol (continuous in the time direction) following the symbol.

For example, when the mapping type of D-DMRS is mapping type B, PUCSH is configured of 12 symbols, and UL-DMRS-add-pos is "1", FL-DMRS is SB0, SB1. The mapped A-DMRS is mapped to SB9 and SB10 (see dotted frame A32 in FIG. 10).

Also in the D-DMRS, the mapping position of the DMRS is notified from the radio base station 10 to the user terminal 20 as in the single DMRS. The user terminal 20 stores the information of the table shown in FIG. 10 in the memory as a table, for example. The user terminal 20 refers to the memory table based on the DMRS mapping type designated from the radio base station 10 and any value of “0, 1” of UL-DMRS-add-pos, and D Determine the position of the symbol to which the DMRS is mapped.

In the 5G specification, the mapping position of the DMRS in the frame A33 of the dashed dotted line of the mapping type B shown in FIG. 10 is not defined. Therefore, the mapping position of the DMRS in the frame A33 of the one-dot chain line of the mapping type B is defined.

It is defined that the DMRSs in the frame A33 of one-dot chain line shown in FIG. 10 are mapped to symbols determined to some extent. Also, in the time direction, it is defined that the last DMRS is mapped to the fourth symbol after the symbols making up the PUSCH.

Thus, by mapping the DMRS to a certain fixed symbol, the performance of channel estimation when DMRSs collide can be improved on average compared to when DMRSs collide with data. Also, by mapping the last DMRS to the fourth symbol after the symbols making up the PUSCH in the time direction, it is possible to improve the interpolation accuracy of channel estimation over the PUSCH.

As shown in FIG. 10, one D-DMRS A-DMRS is defined. That is, in A-DMRS of D-DMRS, UL-DMRS-add-pos defines “0, 1” and does not define 2 or more. The reason why two or more A-DMRSs of D-DMRS are not defined is to suppress the decrease of PUSCH resources by DMRS.

<Frequency hopping of DMRS in UL>
In UL, frequency hopping may be applied in one slot. For example, when one slot is configured by 14 symbols, one slot may be divided into two areas configured by 7 symbols, and frequency hopping may be applied to the two areas.

However, in the 5G specification, the mapping position of DMRS when frequency hopping is applied is not defined. So, in this invention, the mapping position of DMRS when frequency hopping is applied was specified.

FIG. 11 is a diagram for explaining an example of frequency hopping of the DMRS in UL. As shown in FIG. 11, one slot may be divided into a first hop region located in the first half and a second hop region located in the second half in the time direction. In the example of FIG. 11, the second hop region is hopped to a frequency band lower than the first hop region. Note that the second hop region may hop to a frequency band higher than the first hop region.

The seven symbols in each hop area in FIG. 11 are referred to as SB0 to SB6 in order from the left.

A PUCCH is mapped to the first two symbols (SB0 and SB1) of the first hop area in FIG. The number of symbols of PUCCH is not limited to 2 symbols, and may be 1 symbol or 3 symbols.

The DMRS is mapped in each of the first hop region and the second hop region. For example, DMRS may be mapped to SB2 and SB4 in each of the first hop region and the second hop region.

FIG. 12 is a diagram for explaining the mapping position of DMRS in UL. The view of the table shown in FIG. 12 is the same as that of FIG. However, “PUSCH duration in symbols” shown in FIG. 12 indicates the number of symbols in the first hop area, and indicates the number of symbols in the second hop area. Note that the DMRS shown in FIG. 11 is the case of “l ₀ = 2” of the mapping type A, and is mapped to the radio resource based on the mapping position designated by the bold frame A41 in FIG. . That is, the DMRS is mapped to SB2 and SB6 in the first hop area, and mapped to SB2 and SB6 in the second hop area.

Note that, in FIG. 11, PUCCH may be mapped also to the second hop region. Further, in FIG. 11, the DMRSs are mapped to the same symbol position in the first hop region and the second hop region, but may be mapped to different symbol positions in the first hop region and the second hop region. . For example, in the second hop region, instead of mapping DMRS to SB2, DMRS may be mapped to the first symbol (SB0). In this case, a table (information defining a mapping position) as shown in FIG. 12 may be prepared in each of the first hop area and the second hop area. Alternatively, in the case of mapping of DMRS of mapping type A to which frequency hopping is applied, the position of DMRS in the first hop region to which PUCCH is mapped is set based on mapping type A shown in FIG. 12 and PUCCH is not mapped. The position of the DMRS in the second hop region may be set based on the mapping type B shown in FIG.

In the 5G specification, mapping positions of DMRSs of mapping types A and B in frequency hopping are not defined. So, in this invention, the mapping position of DMRS of mapping type A, B in frequency hopping was specified.

The embodiments of the present invention have been described above.

(Hardware configuration)
Note that the block diagram used in the description of the above embodiment shows blocks in units of functions. These functional blocks (components) are realized by any combination of hardware and / or software. Moreover, the implementation means of each functional block is not particularly limited. That is, each functional block may be realized by one physically and / or logically coupled device, or directly and / or indirectly two or more physically and / or logically separated devices. It may be connected by (for example, wired and / or wireless) and realized by the plurality of devices.

For example, the wireless base station 10, the user terminal 20, and the like in one embodiment of the present invention may function as a computer that performs the processing of the wireless communication method of the present invention. FIG. 13 is a diagram showing an example of the hardware configuration of the radio base station 10 and the user terminal 20 according to an embodiment of the present invention. The above-described wireless base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007 and the like. Good.

In the following description, the term "device" can be read as a circuit, a device, a unit, or the like. The hardware configuration of the radio base station 10 and the user terminal 20 may be configured to include one or more of the devices illustrated in the figure, or may be configured without including some devices.

For example, although only one processor 1001 is illustrated, there may be a plurality of processors. Also, the processing may be performed by one processor, or the processing may be performed by one or more processors simultaneously, sequentially, or in other manners. The processor 1001 may be implemented by one or more chips.

Each function in the radio base station 10 and the user terminal 20 performs a calculation by causing the processor 1001 to read predetermined software (program) on hardware such as the processor 1001 and the memory 1002, and performs communication by the communication device 1004 or This is realized by controlling reading and / or writing of data in the memory 1002 and the storage 1003.

The processor 1001 operates, for example, an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including an interface with a peripheral device, a control device, an arithmetic device, a register, and the like. For example, the above-described scheduler 101, transmission signal generation units 102 and 206, coding / modulation units 103 and 207, mapping units 104 and 208, control units 108 and 203, channel estimation units 109 and 204, demodulation / decoding units 110 and 205 And the like may be realized by the processor 1001.

Also, the processor 1001 reads a program (program code), a software module or data from the storage 1003 and / or the communication device 1004 to the memory 1002, and executes various processing according to these. As a program, a program that causes a computer to execute at least a part of the operations described in the above embodiments is used. For example, the scheduler 101 of the radio base station 10 may be realized by a control program stored in the memory 1002 and operated by the processor 1001, or may be realized similarly for other functional blocks. The various processes described above have been described to be executed by one processor 1001, but may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunication line.

The memory 1002 is a computer readable recording medium, and includes, for example, at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), and a RAM (Random Access Memory). It may be done. The memory 1002 may be called a register, a cache, a main memory (main storage device) or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to implement the wireless communication method according to an embodiment of the present invention.

The storage 1003 is a computer readable recording medium, and for example, an optical disc such as a CD-ROM (Compact Disc ROM), a hard disc drive, a flexible disc, a magneto-optical disc (eg, a compact disc, a digital versatile disc, a Blu-ray A (registered trademark) disk, a smart card, a flash memory (for example, a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, and the like may be used. The storage 1003 may be called an auxiliary storage device. The above-mentioned storage medium may be, for example, a database including the memory 1002 and / or the storage 1003, a server or any other suitable medium.

The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via a wired and / or wireless network, and is also called, for example, a network device, a network controller, a network card, a communication module, or the like. For example, the above-described transmission units 105 and 209, antennas 106 and 201, and reception units 107 and 202 may be realized by the communication device 1004.

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

Also, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured by a single bus or may be configured by different buses among the devices.

Also, the radio base station 10 and the user terminal 20 may be microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), etc. It may be configured to include hardware, and part or all of each functional block may be realized by the hardware. For example, processor 1001 may be implemented in at least one of these hardware.

(Information notification, signaling)
In addition, notification of information is not limited to the aspect / embodiment described herein, and may be performed by other methods. For example, notification of information may be physical layer signaling (for example, Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (for example, Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, It may be implemented by broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or a combination thereof. Also, RRC signaling may be referred to as an RRC message, and may be, for example, an RRC connection setup (RRC Connection Setup) message, an RRC connection reconfiguration (RRC Connection Reconfiguration) message, or the like.

(Adaptive system)
Each aspect / embodiment described in the present specification is 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-Wide Band), Bluetooth The present invention may be applied to a system using (registered trademark), other appropriate systems, and / or an advanced next-generation system based on these.

(Processing procedure etc.)
As long as there is no contradiction, the processing procedure, sequence, flow chart, etc. of each aspect / embodiment described in this specification may be reversed. For example, for the methods described herein, elements of the various steps are presented in an exemplary order and are not limited to the particular order presented.

(Operation of base station)
The specific operation supposed to be performed by the base station (radio base station) in this specification may be performed by the upper node in some cases. In a network of one or more network nodes with a base station, the various operations performed for communication with the terminals may be the base station and / or other network nodes other than the base station (eg, It is obvious that this may be performed by, but not limited to, MME (Mobility Management Entity) or S-GW (Serving Gateway). Although the case where one other network node other than a base station was illustrated above was illustrated, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

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

(Handling of input / output information etc.)
The input / output information or the like may be stored in a specific place (for example, a memory) or may be managed by a management table. Information to be input or output may be overwritten, updated or added. The output information etc. may be deleted. The input information or the like may be transmitted to another device.

(Judgment method)
The determination may be performed by a value (0 or 1) represented by one bit, may be performed by a boolean value (Boolean: true or false), or may be compared with a numerical value (for example, a predetermined value). Comparison with the value).

(software)
Software may be called software, firmware, middleware, microcode, hardware description language, or any other name, and may be instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules. Should be interpreted broadly to mean applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc.

Also, software, instructions, etc. may be sent and received via a transmission medium. For example, software may use a wireline technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or a website, server or other using wireless technology such as infrared, radio and microwave When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission medium.

(Information, signal)
The information, signals, etc. described herein may be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, symbols, chips etc that may be mentioned throughout the above description may be voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any of these May be represented by a combination of

The terms described in the present specification and / or the terms necessary for the understanding of the present specification may be replaced with terms having the same or similar meanings. For example, the channels and / or symbols may be signals. Also, the signal may be a message. Also, the component carrier (CC) may be called a carrier frequency, a cell or the like.

("System", "Network")
The terms "system" and "network" as used herein are used interchangeably.

(Name of parameter, channel)
In addition, the information, parameters, and the like described in the present specification may be represented by absolute values, may be represented by relative values from predetermined values, or may be represented by corresponding other information. . For example, radio resources may be indexed.

The names used for the parameters described above are in no way limiting. In addition, the formulas etc. that use these parameters may differ from those explicitly disclosed herein. Since various channels (eg PUCCH, PDCCH etc.) and information elements (eg TPC etc.) can be identified by any suitable names, the various names assigned to these various channels and information elements can be Is not limited.

(base station)
A base station (radio base station) can accommodate one or more (e.g., three) cells (also called sectors). If the base station accommodates multiple cells, the entire coverage area of the base station can be divided into multiple smaller areas, each smaller area being a base station subsystem (eg, a small base station RRH for indoor use: Remote Communication service can also be provided by Radio Head. The terms "cell" or "sector" refer to a part or all of the coverage area of a base station and / or a base station subsystem serving communication services in this coverage. Furthermore, the terms "base station", "eNB", "gNB", "cell" and "sector" may be used interchangeably herein. A base station may be called in terms of a fixed station (Node station), NodeB, eNodeB (eNB), gNodeB (gNB) access point, access point, femtocell, small cell, and the like.

(Terminal)
The user terminal may be 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 communication device, a mobile subscriber station, an access terminal, a mobile terminal by a person skilled in the art It may also be called a terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, a UE (User Equipment), or some other suitable term.

(Meaning and interpretation of terms)
The terms "determining", "determining" as used herein may encompass a wide variety of operations. "Judgment", "decision" are, for example, judging, calculating, calculating, processing, processing, deriving, investigating, looking up (for example, a table) (Searching in a database or another data structure), ascertaining may be regarded as “decision”, “decision”, etc. Also, "determination" and "determination" are receiving (e.g. receiving information), transmitting (e.g. transmitting information), input (input), output (output), access (accessing) (for example, accessing data in a memory) may be regarded as “judged” or “decided”. Also, "judgement" and "decision" are to be considered as "judgement" and "decision" that they have resolved (resolving), selecting (selecting), choosing (choosing), establishing (establishing), etc. May be included. That is, "judgment""decision" may include considering that some action is "judged""decision".

The terms "connected", "coupled" or any variants thereof mean any direct or indirect connection or coupling between two or more elements, It can include the presence of one or more intermediate elements between two elements that are “connected” or “coupled”. The coupling or connection between elements may be physical, logical or a combination thereof. As used herein, the two elements are by using one or more wires, cables and / or printed electrical connections, and radio frequency as some non-limiting and non-exclusive examples. It can be considered "connected" or "coupled" to one another by using electromagnetic energy such as electromagnetic energy having wavelengths in the region, microwave region and light (both visible and invisible) regions.

The reference signal may be abbreviated as RS (Reference Signal), and may be called a pilot (Pilot) according to the applied standard. Also, DMRS may be another corresponding name, such as demodulation RS or DM-RS.

As used herein, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

The “parts” in the configuration of each of the above-described devices may be replaced with “means”, “circuit”, “device” or the like.

As long as “including”, “comprising”, and variations thereof are used in the present specification or claims, these terms as well as the term “comprising” are inclusive. Intended to be Further, it is intended that the term "or" as used in the present specification or in the claims is not an exclusive OR.

A radio frame may be comprised of one or more frames in the time domain. One or more frames in the time domain may be referred to as subframes, time units, and so on. A subframe may be further comprised of one or more slots in the time domain. The slot may be further configured with one or more symbols (such as orthogonal frequency division multiplexing (OFDM) symbols, single carrier-frequency division multiple access (SC-FDMA) symbols, etc.) in the time domain.

A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units when transmitting a signal. A radio frame, a subframe, a slot, a minislot, and a symbol may be another name corresponding to each.

For example, in the LTE system, the base station performs scheduling to assign radio resources (frequency bandwidth usable in each mobile station, transmission power, etc.) to each mobile station. The minimum time unit of scheduling may be called a TTI (Transmission Time Interval).

For example, one subframe may be called a TTI, a plurality of consecutive subframes may be called a TTI, one slot may be called a TTI, and one minislot may be called a TTI.

A resource unit is a resource allocation unit in time domain and frequency domain, and may include one or more consecutive subcarriers in frequency domain. Also, the time domain of the resource unit may include one or more symbols, and may be one slot, one minislot, one subframe, or one TTI long. One TTI and one subframe may be configured of one or more resource units, respectively. Also, resource units may be referred to as resource blocks (RBs), physical resource blocks (PRBs: physical RBs), PRB pairs, RB pairs, scheduling units, frequency units, and subbands. Also, a resource unit may be configured of one or more REs. For example, 1 RE may be a resource of a unit smaller than the resource unit serving as a resource allocation unit (for example, the smallest resource unit), and is not limited to the designation RE.

The above-described radio frame structure is merely an example, and the number of subframes included in the radio frame, the number of slots included in the subframe, the number of minislots included in the subframe, and the symbols and resource blocks included in the slots. The number and the number of subcarriers included in the resource block can be variously changed.

Throughout the disclosure, when articles are added by translation, such as, for example, a, an, and the in English, these articles are not clearly indicated by the context: It shall contain several things.

(Variation of aspect etc.)
Each aspect / embodiment described in this specification may be used alone, may be used in combination, and may be switched and used along with execution. In addition, notification of predetermined information (for example, notification of "it is X") is not limited to what is explicitly performed, but is performed by implicit (for example, not notifying of the predetermined information) It is also good.

Although the present invention has been described above in detail, it is apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be embodied as modifications and alterations without departing from the spirit and scope of the present invention defined by the description of the claims. Accordingly, the description in the present specification is for the purpose of illustration and does not have any limiting meaning on the present invention.

Reference Signs List 10 radio base station 20 user terminal 101 scheduler 102, 206 transmission signal generation unit 103, 207 encoding / modulation unit 104, 208 mapping unit 105, 209 transmission unit 106, 201 antenna 107, 202 reception unit 108, 203 control unit 109, 204 channel estimation unit 110, 205 demodulation and decoding unit

Claims (6)

1. A transmitter configured to transmit a downlink radio link signal in which the first demodulation reference signal is mapped to the leading symbol of the resource allocation unit;
   Control the mapping position in the resource allocation unit of the second demodulation reference signal based on the number of symbols of the resource allocation unit and the number of second demodulation reference signals mapped in the resource allocation unit Control unit, and
   Equipped with
   The control unit
   When the number of symbols in the resource allocation unit is eight or more and the number of the second demodulation reference signals is one or more, one second symbol within three symbols from the last symbol of the resource allocation unit. Map the demodulation reference signal,
   Wireless communication device.
2. The control unit
   When the number of the second demodulation reference signals is two or more, the first and second demodulation reference signals are mapped at equal intervals.
   The wireless communication device according to claim 1.
3. The control unit
   When the number of second demodulation reference signals in the resource allocation unit is 2, the number of symbols in the resource allocation unit is 2n or (2n + 1) (where n is 4, 5, or 6) Mapping the second demodulation reference signal in the same position from the beginning of the resource allocation unit;
   The wireless communication device according to claim 1.
4. A transmitter configured to transmit a downlink radio signal in which a first demodulation reference signal is mapped two consecutive symbols from the beginning of a resource allocation unit;
   Control the mapping position in the resource allocation unit of the second demodulation reference signal based on the number of symbols of the resource allocation unit and the number of second demodulation reference signals mapped in the resource allocation unit Control unit, and
   Equipped with
   The control unit
   When the number of symbols of the resource allocation unit is eight or more and the number of the second demodulation reference signals is one or more, the second demodulation reference signals are mapped continuously for two symbols, and Mapping at least one of the second demodulation reference signals within 3 symbols from the last symbol of the resource allocation unit;
   Wireless communication device.
5. A transmitter configured to transmit an uplink radio link signal in which a first demodulation reference signal is mapped to a leading symbol of a resource allocation unit;
   Control the mapping position in the resource allocation unit of the second demodulation reference signal based on the number of symbols of the resource allocation unit and the number of second demodulation reference signals mapped in the resource allocation unit Control unit, and
   Equipped with
   The control unit
   When the number of symbols of the resource allocation unit is 14 and the number of the second demodulation reference signals is 1 or more, one second demodulation within 5 symbols from the last symbol of the resource allocation unit Mapping the reference signal for
   Wireless communication device.
6. A transmitter configured to transmit an uplink radio link signal in which a first demodulation reference signal is mapped two consecutive symbols from the beginning of a resource allocation unit;
   Control the mapping position in the resource allocation unit of the second demodulation reference signal based on the number of symbols of the resource allocation unit and the number of second demodulation reference signals mapped in the resource allocation unit Control unit, and
   Equipped with
   The control unit
   When the number of symbols of the resource allocation unit is 13 or more and the number of the second demodulation reference signals is 1, two symbols of the second demodulation reference signal are mapped consecutively, and Mapping at least one of the second demodulation reference signals within 5 symbols from the last symbol of the resource allocation unit;
   Wireless communication device.
   

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