Patent Description:
Studies have been carried out on communication systems so called the <NUM>th Generation mobile communication systems (<NUM>). In <NUM>, studies have been carried out on flexibly providing functions for each of use cases which require an increase in communication traffic, an increase in the number of terminals to be connected, high reliability, and low latency. Typical use cases include the following three: enhanced Mobile Broadband (eMBB); massive Machine Type Communications (mMTC); and Ultra Reliable and Low Latency Communications (URLLC). In the 3rd Generation Partnership Project (3GPP), which is an international standardization organization, further advancement of communication systems has been under study in both aspects of advancement of the LTE systems, and New Radio Access Technology (New RAT) (e.g., see Non-Patent Literature (hereinafter, referred to as "NPL") <NUM>).

<CIT>
relates to a wireless communication terminal which, when SRSs are simultaneously transmitted between CCs and between antenna ports, avoids increasing the effect of bit rounding errors of D/A converters when the number of antenna ports set for SRS transmission differs between CCs. 3GPP document by <NPL> relates to the number of DL PT-RS ports and provides a text proposal for TS38. <CIT>, relates to a system and method for uplink multi-antenna power control in a communications system are provided. <CIT> and <CIT> relate to the suppression of degradation of uplink communication quality when a user terminal connects to multiple radio base stations by application of dual connectivity (DC).

The invention is defined only in the appended independent claims.

In New RAT, for example, signals of a frequency equal to or greater than <NUM> is used as a carrier wave. In particular, when a high frequency band and high modulation order are used, error rate characteristics are degraded due to Common Phase Error (CPE) or Inter-Carrier Interference (ICI), which occurs due to a phase noise of a local oscillator (e.g., see NPL <NUM>). In this respect, in New RAT, performing of CPE correction or ICI correction (hereinafter, may be referred to as "CPE/ICI correction") using Phase Tracking Reference Signal (PT-RS) in addition to channel equalization by receivers have been under study.

Further studies regarding transmission power control in antenna ports through which a PT-RS is transmitted (hereinafter, may be referred to as "PT-RS port") are necessary, however.

One non-limiting example of the present disclosure facilitates providing a transmitter and a transmission method each capable of appropriately performing transmission power control in a PT-RS port.

According to one example of this disclosure, transmission power control in PT-RS ports can be appropriately performed.

Additional benefits and advantages of the disclosed examples will become apparent from the specification and drawings. The benefits and/or advantages may be individually obtained by various examples and features of the specification and drawings, which need not all be provided in order to obtain one or more of such benefits and/or advantages.

Hereinafter, a detailed description will be given of examples of the present disclosure with reference to the accompanying drawings.

In a case where the number of antenna ports (PT-RS ports) for transmitting PT-RS and the number of antenna ports (DMRS ports) for transmitting data and DMRS are different from each other, the transmission power per Resource Element (hereinafter, ma be referred to as "RE" and/or resource elements may be collectively referred to as "RE") of PT-RS in one antenna port may be configured to be large compared with the transmission power per RE of data in one antenna port to be transmitted and received between the same base station and mobile station. This transmission power control for PT-RS may be referred to as "power boosting. " Power boosting of PT-RS improves the PT-RS reception accuracy and CPE/ICI estimation accuracy, and thus, improvement in the transmission speed/transmission efficiency can be expected.

It is also assumed that coherent transmission (full-coherent transmission), non-coherent transmission (non-coherent transmission), and partial coherent transmission (partial-coherent transmission) are supported in codebook based uplink transmission of NR. Among these transmissions, there is an opinion that power boosting of PT-RS is difficult in non-coherent transmissions and partial coherent transmissions because the upper limit of transmission power (maximum transmission power) is provided for each antenna port. However, for more accurate CPE/ICI estimation, PT-RS should be subjected to power boosting as much as possible in all transmission schemes. Therefore, a method for applying power boosting to PT-RS (PT-RS power boosting) in non-coherent transmission or partial coherent transmission needs to be discussed.

The higher the frequency band to which the signal is assigned or the higher the modulation order to be used for the signal, the greater the effect of CPE/ICI for the error rate characteristics is. Therefore, as described above, in a case where a high-frequency band and/or high modulation order is used, performing of CPE/ICI correction using PT-RS in addition to channel equalization in receivers has been discussed.

PT-RS is mapped with high density on the time domain compared with a reference signal for channel estimation (for demodulation) (Demodulation Reference Signal (DMRS) in order to track CPE/ICI that fluctuates randomly in time. Specifically, it is assumed that PT-RS is mapped with a density of each symbol, one symbol of two adjacent symbols or one symbol of four adjacent symbols, for example. Further, because of the characteristics that the variation between CPE/ICI subcarriers is small, PT-RS is mapped with a relatively low density in frequency domain. Specifically, it is assumed that PT-RS is mapped in a density, such as one for each Resource Block (RB) (e.g., one subcarrier), one for every adjacent two RBs, or one for every adjacent four RBs.

According to the agreements regarding PT-RS in 3GPP RAN1 #<NUM>, PT-RS is used between a base station (BS, eNB, gNB) and a mobile station (terminal, UE) as indicated by higher layer signaling (e.g., RRC (Radio Resource Control) signaling) from the base station. It is also assumed that assignment densities of PT-RS in the time domain and frequency domain flexibly change depending on the modulation order or bandwidth and/or the like used between the base station and the mobile station.

In addition, a method for determining the assignment density of PT-RS (hereinafter, may be referred to as "PT-RS assignment density") by mobile stations has been discussed. As one method, there is a method in which the PT-RS assignment density is indicated from the base station by a PT-RS dedicated control signal (e.g., Downlink Control Information (DCI)) or an RRC signal) (explicit indication). As another method, there is a method in which a correspondence relationship between the PT-RS assignment density and another parameter (e.g., such as a modulation order or bandwidth) is previously determined, and a mobile station determines the PT-RS assignment density by checking the correspondence relationship with the other parameter indicated by DCI at the time of communication (implicit indication). Note that there is a possibility that a method other than these methods may be used.

Meanwhile, DMRS used for channel estimation is mapped with a high density in frequency domain and a low density in time domain compared with PT-RS, because the change in channel characteristics in frequency domain is large and the change in time domain is not as large as phase noise. Furthermore, in order to set the timing of data demodulation earlier, the introduction of a front-loaded DMRS which is mapped in a front position of a slot is assumed in New RAT.

Further, mapping of PT-RS to the same antenna port as a certain DMRS (this port may be referred to as "PT-RS port") and application of the same precoding as a DMRS port to PT-RS have been discussed. For this reason, there is a possibility that PT-RS may be used in the receiver for channel estimation as with DMRS.

Further, there is a possibility that PT-RS is defined as a part of DMRS. In this case, DMRS used as PT-RS is mapped with a high density compared with other DMRSs in time domain and is mapped with a low density compared with other DMRSs in frequency domain. Further, the reference signal used to correct CPE/ICI generated due to phase noise may also be referred to as a term other than "PT-RS.

It is also assumed that Multiple Input Multiple Output (MIMO) is used in New RAT. That is, the base station and one or more mobile stations within a cell formed by the base station are capable of performing transmission and reception, using a plurality of antenna ports corresponding to different precoding pieces using the same time and frequency resources.

In the base station and the mobile station, there are limits on their respective maximum transmission powers. For this reason, it is assumed that the operation is performed such that the sum of the transmission powers of the plurality of antenna ports used for data transmission does not exceed the maximum value of the transmission power. Basically, it is assumed that the transmission powers for data of the antenna ports are equal to each other. Therefore, for example, in case of transmission of data or a reference signal, using one antenna port and in case of transmission of data or a reference signal, using n antenna ports, the transmission power per antenna port is considered to be n times larger in the former than that in the latter.

PT-RS is transmitted and received between the base station and each of the mobile stations in a cell formed by the base station. Herein, in a group of antenna ports (may be referred to as a DMRS port group) sharing a local oscillator of a transmitter (base station in downlink and mobile stations in uplink), the values of CPE/ICI are likely to be the same. For this reason, it is assumed that PT-RS is transmitted from any one antenna port of this group.

Furthermore, it is considered that PT-RS transmitted and received with respect to one mobile station is subjected to time/frequency/spatially orthogonal multiplexing with respect to data. Therefore, in a case where PT-RS is transmitted in a certain antenna port (a certain RE), nothing is transmitted on the RE in other antenna ports used by the mobile station. In other words, in a certain RE, power is used for PT-RS in one antenna port, and no power is used (nothing is transmitted) at all in the other antenna ports.

In New RAT, the following transmission power control, i.e., "PT-RS power boosting" has been under discussion. In this transmission power control, the transmission power per RE of one antenna port for PT-RS is made larger than the transmission power per RE of one antenna port for data, using the power of resources not used by the other antenna ports, by the amount of power of the not used resources.

As an example, <FIG> illustrates a mapping example of DMRS, PT-RS and data in MIMO. In RE (symbol × subcarrier) at the lowermost subcarrier of <FIG>, PT-RS is transmitted in antenna port <NUM>. At this time, in the same RE group (i.e., the lowest subcarrier) as the RE group on which PT-RS is transmitted in antenna port <NUM>, nothing is transmitted in antenna port <NUM> (blank).

<FIG> illustrates an example of transmission power allocation in RE of each of antenna ports <NUM> and <NUM> before and after PT-RS power boosting is performed. In the example illustrated in <FIG>, antenna port <NUM> adds (power boosting) the power of RE not used in antenna port <NUM> to PT-RS and transmits the PT-RS. Therefore, after PT-RS power boosting, as illustrated in <FIG>, not only the RE on which PT-RS is transmitted but also the transmission power of the entire antenna port <NUM> becomes larger than the transmission power of antenna port <NUM>.

According to the description of uplink PT-RS power boosting in NPL <NUM>, herein, when PT-RS is transmitted in one antenna port (one PT-RS port) in uplink, the ratio representing "how many times the power of data is the power of PT-RS" for every RE in PT-RS port is, ρPTRS,i, and is obtained by the following equation. [Equation <NUM>] <MAT>.

In Equation <NUM>, nlayelPUSCH represents the number of layers of transmission data configured in the base station (i.e., the receiver).

For uplink transmission of New RAT, two transmission methods (e.g., codebook based transmission (codebook based UL transmission) and non-codebook based transmission (non-codebook based UL transmission) are assumed (e.g., see NPL <NUM>). In codebook based transmission, the number of available precoding matrices differs depending on the type of coherent transmission that can be supported by the mobile station. It is assumed that the types of the capability of the mobile station (UE capability) for coherent transmission are divided into the following three.

The first one, which is "fullAndPartialAndNonCoherent," indicates the presence of the capability of supporting all types of coherent transmissions. The second one, which is "partialAndNonCoherent," indicates the presence of the capability of supporting partial coherent transmission and non-coherent transmission. The third one, which is "Non-Coherent," indicates the presence of the capability of supporting only non-coherent transmission.

"Non-coherent transmission," herein, is a transmission scheme in which independent precoding is applied to different antenna panels in a transmitter in which a plurality of non-uniform antenna panels are implemented (e.g., see NPL <NUM>). In this case, data on different layers is transmitted from different panels. "Coherent transmission" is a transmission scheme in which data on all layers can be transmitted from all antenna panels, respectively, in a transmitter in which uniform antenna panels are implemented. Further, "partial coherent transmission" is a transmission method in which data of a part of a layer group is transmitted from a part of an antenna panel group, and data on other layers is transmitted from the remaining part of the antenna panel group.

Table <NUM> indicates a precoding matrix assumed to be available when the number of layers is two and the number of antenna ports is two (e.g., see is NPL <NUM>). It is assumed that all matrices in Table <NUM> are available for coherent transmission while only the leftmost matrix in Table <NUM> is available for non-coherent transmission.

<FIG> shows examples of non-coherent transmission and coherent transmission. As illustrated in <FIG>, in non-coherent transmission, the data of the respective layers (Layer #<NUM> and # <NUM>) are transmitted from independent panels by the precoding matrix.

<FIG> illustrates a transmission example of a case where PT-RS is transmitted in non-coherent transmission. As described above, PT-RS may be transmitted in some of the antenna ports (Port #<NUM> in <FIG>). Thus, for non-coherent transmission (or partial coherent transmission), the transmission power of the panel transmitting PT-RS (panel corresponding to Port #<NUM> in <FIG>) may be greater than the transmission power of the other panel (panel corresponding to Port #<NUM> in <FIG>). Furthermore, when PT-RS illustrated in <FIG> is subjected to power boosting, the transmission power of the panel may exceed the transmittable power as a capability. As a result, the signal including PT-RS may be distorted or PT-RS may not be transmitted with the intended power, resulting in degradation of CPE/ICI estimation accuracy, which possibly causes degradation of data transmission efficiency.

Accordingly, in one aspect of the present disclosure, a description will be given of a method for appropriately performing a transmission power control (including power boosting) for PT-RS in non-coherent transmission or partial coherent transmission, thereby improving the CPE/ICI estimation accuracy and improving the data transmission efficiency.

In New RAT, use of a Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) scheme in downlink (direction from a base station to a mobile station) is assumed. Meanwhile, both the CP-OFDM scheme and Discrete Fourier Transform-Spread OFDM (DFT-S-OFDM) scheme in uplink (direction from a mobile station to a base station) have been discussed, and it is assumed that the communication schemes are used while they are switched so as to match the communication environment.

In New RAT, transmission of remaining transmission power information (PHR: Power Headroom Report) as in LTE in uplink transmission is assumed. That is, the mobile station, which is the transmitter, reports the value obtained by subtracting the transmission power for the actual data from the maximum transmission power of the mobile station to the base station, as PHR. However, the value of PHR is not the remaining transmission power of each antenna port, and the value of PHR is the value as the entire mobile station as a result of aggregating all antenna ports.

A communication system according to the present example includes transmitter <NUM> and receiver <NUM>. That is, in uplink, the transmitter is a mobile station and the receiver is a base station. In downlink, the transmitter is a base station and the receiver is a mobile station.

<FIG> is a block diagram illustrating a configuration of a part of transmitter <NUM> according to the present example. In transmitter <NUM> illustrated in <FIG>, controller <NUM> determines the transmission power for phase tracking reference signal (PT-RS) and the data signal within a range not exceeding the maximum transmission power for each antenna port, and transmitter <NUM> transmits PT-RS and the data signal with the determined transmission power.

<FIG> is a block diagram illustrating a configuration of transmitter <NUM> according to the present example. In <FIG>, transmitter <NUM> includes controller <NUM>, error correction encoder <NUM>, modulator <NUM>, signal assigner <NUM>, transmitter <NUM>, and antenna <NUM>.

Information such as the remaining transmission power of transmitter <NUM> is inputted to controller <NUM>. Controller <NUM> determines the transmission power for data or PT-RS and/or the like based on this information and/or the like. Then, controller <NUM> outputs the transmission power information indicating the determined transmission power to signal assigner <NUM>.

Error correction encoder <NUM> applies error correction coding on the transmission data signal to be inputted and outputs the data signal after the error correction coding to modulator <NUM>.

Modulator <NUM> applies modulation processing to the signal to be inputted from error correction encoder <NUM>, and outputs the data signal after the modulation to signal assigner <NUM>.

Signal assigner <NUM> maps DMRS, PT-RS, or the data signal to be inputted from modulator <NUM> to the time and frequency domain, and outputs signal after the mapping to transmitter <NUM>. At this time, signal assigner <NUM> configures the transmission power for each signal based on the transmission power information to be inputted from controller <NUM>.

Transmitter <NUM> applies radio transmission processing, such as frequency conversion using a carrier wave, to the signal to be inputted from signal assigner <NUM>, and outputs the signal after the radio transmission processing to antenna <NUM>.

Antenna <NUM> radiates the signal to be inputted from transmitter <NUM> toward receiver <NUM>.

<FIG> is a block diagram illustrating a configuration example of receiver <NUM> according to the present example. In <FIG>, receiver <NUM> includes antenna <NUM>, receiver <NUM>, signal demultiplexer <NUM>, channel estimator <NUM>, CPE/ICI estimator <NUM>, data demodulator <NUM>, and error correction encoder <NUM>.

Antenna <NUM> receives the signal transmitted from transmitter <NUM> (see <FIG>) and outputs the received signal to receiver <NUM>.

Receiver <NUM> applies radio reception processing, such as frequency conversion to the received signal to be inputted from antenna <NUM>, and outputs the signal after the radio reception processing to signal demultiplexer <NUM>.

Signal demultiplexer <NUM> identifies the positions of the time and frequency domain to which the data signal, DMRS, and PT-RS in the signal to be inputted from receiver <NUM> are mapped, and demultiplexes the data signal, DMRS, and PT-RS. Signal demultiplexer <NUM> outputs the data signal in the demultiplexed signal to data demodulator <NUM>, and outputs DMRS to channel estimator <NUM> and CPE/ICI estimator <NUM>, and outputs PT-RS to channel estimator <NUM> and CPE/ICI estimator <NUM>.

Channel estimator <NUM> performs channel estimation, using DMRS to be inputted from signal demultiplexer <NUM>, and outputs a channel estimate (channel information) to data demodulator <NUM>. Note that, channel estimator <NUM> may perform channel estimation, using PT-RS to be inputted from signal demultiplexer <NUM>. In this case, channel estimator <NUM> may perform channel estimation based on PT-RS, using information about the amplitude of PT-RS to be inputted (e.g., the amplitude (power) ratio of PT-RS to be transmitted from transmitter <NUM> and the data signal).

CPE/ICI estimator <NUM> estimates CPE/ICI, using PT-RS and DMRS to be inputted from signal demultiplexer <NUM>, and outputs the CPE/ICI estimate to data demodulator <NUM>.

Data demodulator <NUM> demodulates the data signal to be inputted from signal demultiplexer <NUM>, using a channel estimate to be inputted from channel estimator <NUM> and a CPE/ICI channel estimate to be inputted from CPE/ICI estimator <NUM>. Data demodulator <NUM> outputs a demodulation signal to error correction decoder <NUM>.

Error correction decoder <NUM> decodes the demodulation signal to be inputted from data demodulator <NUM> and outputs the resultant received data signal.

Next, operations of transmitter <NUM> and receiver <NUM> will be described in detail.

<FIG> is a flowchart illustrating the processing flow of transmitter <NUM>.

Note that transmitter <NUM> performs, for example, non-coherent transmission or partial coherent transmission.

First, transmitter <NUM> (controller <NUM>) configures the transmission power for PT-RS and the data signal (DMRS) (ST101). At this time, transmitter <NUM> may configure the defined transmission power for the data signal and apply power boosting to PT-RS.

Next, transmitter <NUM> (controller <NUM>) determines whether or not adjustment of the configured transmission power is required (ST102). For example, transmitter <NUM> determines that adjustment of the transmission power is required in a case where the remaining power for transmitting the signal (PT-RS and data signal) with the transmission power configured in ST101 is not sufficient in the antenna port (PT-RS port) from which the PT-RS is transmitted.

When adjustment of the transmission power is not required (ST102: NO), transmitter <NUM> proceeds to processing of ST104.

Meanwhile, in a case where adjustment of the transmission power is required (ST102: YES), transmitter <NUM> (controller <NUM>) adjusts the transmission power such that the transmission power does not exceed the maximum transmission power for each antenna port (i.e., to be equal to or less than the maximum transmission power) (ST103). That is, transmitter <NUM> reduces the transmission power such that the transmission power does not exceed the maximum transmission power for each antenna port in a case where the remaining power for transmitting the signal with the configured transmission power is not sufficient.

Then, transmitter <NUM> (transmitter <NUM>) transmits the signal from each antenna port with the transmission power configured in ST101 or the transmission power adjusted in ST103 (ST104).

Next, a detailed description will be given of Operation Examples <NUM> to <NUM> of the transmission power adjustment (ST103 in <FIG>) by transmitter <NUM> in a case where the remaining transmission power for transmitting the signal with the configured transmission power is not sufficient.

Note that, hereinafter, a description will be given, as an example, of a case where data (DMRS) and PT-RS are assigned in antenna port <NUM>, and data (DMRS) is assigned in antenna port <NUM>. Transmitter <NUM> also applies power boosting to PT-RS in non-coherent or partial coherent transmissions, for example, using a high frequency band and high modulation order.

In addition, the left sides of <FIG> illustrate the transmission power for each RE to be configured for the data and PT-RS at each of antenna ports <NUM> and <NUM> before (before adjustment) reducing the transmission power, and the right sides of <FIG> illustrate the transmission power for each of antenna ports <NUM> and <NUM> after (after adjustment) reducing the transmission power, and the transmission power for each RE of the data and PT-RS.

First, transmitter <NUM>, at the i-th PT-RS port, ρPTRS, i is the ratio representing "how many times the power for data is the power for PT-RS" for every RE, and is determined by the following equation. [Equation <NUM>] <MAT>.

Herein, NPTRS indicates the number of PT-RS ports (the # of PT-RS ports configured with the TX) configured for transmitter <NUM>. Further, nDMRSPTRS, i indicates the number of DMRS ports belonging to the DMRS port group associated with the i-th PT-RS port (the # of DMRS ports associated with PT-RS port i). For example, in the example illustrated in <FIG>, NPTRS = <NUM>, and nDMRSPTRS,i = <NUM>.

Note that, transmitter <NUM> may calculate the ratio ρPTRS,i using Equation <NUM> instead of Equation <NUM>.

Transmitter <NUM> then reduces (adjust) the transmission power for the signal such that the transmission power does not exceed the maximum transmission power for each antenna port.

<FIG> illustrates an example of the transmission power adjustment in Operation Example <NUM>.

As illustrated in <FIG>, transmitter <NUM> reduces the transmission power for the PT-RS and data signal to be transmitted from all antenna ports <NUM> and <NUM> while maintaining the power ratio ρPTRS,i between the data and PT-RS before and after the adjustment. That is, transmitter <NUM> makes a reduction for the PT-RS and data signal of antenna port <NUM>, which is the PT-RS port, as well as the transmission power of the data signal of antenna port <NUM>, which is the other antenna port.

Thus, even after adjustment of the transmission power, the transmission power of the data becomes constant (the same) between antenna port, so that transmitter <NUM> can fairly transmit the data on all the antenna ports.

In addition, since the ratio of the transmission power between the data and PT-RS does not change before and after adjustment of the transmission power, the reception processing using the ratio is not affected.

Further, in a case where receiver <NUM> receives the information indicating that "the remaining power for performing transmission with the configured transmission power in the PT-RS antenna port of transmitter <NUM> is not sufficient," receiver <NUM> may estimate the amplitude (power) ratio between PT-RS and the data from this information and perform channel estimation, using the PT-RS based on the estimated ratio.

<FIG> illustrates an example of transmission power adjustment in Operation Example <NUM>.

As illustrated in <FIG>, transmitter <NUM> reduces the transmission power for the PT-RS and data signal transmitted in PT-RS port (antenna port <NUM>) while maintaining the power ratio ρPTRS,i between the data and PT-RS before and after the adjustment. That is, transmitter <NUM> does not reduce the transmission power in antenna port <NUM> which is not a PT-RS port, although transmitter <NUM> reduces the transmission power in the PT-RS port.

As a result, in the PT-RS port, the ratio of the transmission power between the data and PT-RS does not change before and after adjustment of the transmission power, so that the reception processing using the ratio is not affected.

Further, in the antenna ports other than PT-RS ports, since the transmission power of the data is not reduced, it is made possible to prevent degradation of the reception accuracy of data in receiver <NUM>.

As illustrated in <FIG>, transmitter <NUM> reduces the transmission power for the data in the PT-RS port (antenna port <NUM>) while maintaining the transmission power for PT-RS without reduction. More specifically, in Operation Example <NUM>, transmitter <NUM> does not maintain the power ratio ρPTRS,i between the data and PT-RS before adjustment.

As a result, the transmission power for PT-RS is not reduced in the PT-RS port, so that it is made possible to prevent degradation of the reception accuracy of PT-RS in receiver <NUM>.

As illustrated in <FIG>, transmitter <NUM> reduces the transmission power by transmitting nothing on some RE of the RE to which the data is mapped in the PT-RS port (antenna port <NUM>). That is, in Operation Example <NUM>, transmitter <NUM> reduces the transmission power on some RE to which the data signal has been mapped, and maintains the transmission power for the PT-RS and the data signal mapped to another part of the RE without reduction.

As a result, since the transmission power for PT-RS and data in the RE to be actually transmitted from transmitter <NUM> is not reduced in the PT-RS port, it is made possible to prevent degradation of the reception accuracy of PT-RS and data in receiver <NUM>.

As illustrated in <FIG>, transmitter <NUM> reduces the transmission power for PT-RS to the transmission power for the data signal in the PT-RS port (antenna port <NUM>). That is, transmitter <NUM> reduces the transmission power for PT-RS and does not reduce the transmission power for the data signal in the PT-RS port.

In other words, as illustrated in <FIG>, transmitter <NUM> sets the power ratio ρPTRS, i=<NUM> between the data and PT-RS, and transmits the PT-RS with the same "power per antenna port, per RE" as the data. In other words, transmitter <NUM> releases power boosting of PT-RS.

Thus, the transmission power for the data signal is not reduced, so that it is made possible to prevent degradation of the reception accuracy of data in receiver <NUM>.

Note that, in <FIG>, the case has been described in which the transmission power for PT-RS is reduced to the transmission power for the data signal, but without limitation to this case, transmitter <NUM> may reduce the transmission power for PT-RS such that the transmission power for PT-RS does not to exceed the maximum transmission power of the PT-RS port. That is, the transmission power for PT-RS after adjustment may be larger or smaller than the transmission power for the data signal.

Operation Examples <NUM> to <NUM> have been described, thus far.

As described above, in this example, transmitter <NUM> transmits a data signal with a defined transmission power while subjecting PT-RS to power boosting and transmitting the PT-RS, when performing non-coherent transmission or partial coherent transmission. At this time, in a case where the remaining power for transmission with the configured transmission power is not sufficient, transmitter <NUM> adjusts the transmission power within a range not exceeding the maximum transmission power for each antenna port.

That is, transmitter <NUM> configures the transmission power for PT-RS and a signal (such as data) to be transmitted simultaneously with the PT-RS within a range not exceeding the maximum transmission power for each antenna port. This configuration of transmission power may include application and release of power boosting of PT-RS. Further, in a case where the transmission power configured in a PT-RS port exceeds the maximum transmission power for the PT-RS port, transmitter <NUM> adjusts the transmission power to be less than or equal to the maximum transmission power for each antenna port.

Thus, transmitter <NUM> is capable of transmitting PT-RS with the highest possible transmission power within a range not exceeding the maximum transmission power for each antenna port, in accordance with the remaining power of transmitter <NUM> even in a transmission for which power cannot be adjusted between antenna ports as in non-coherent transmission or partial coherent transmission. Thus, the noise estimation accuracy can be improved in receiver <NUM>, and the improvement of the transmission speed/transmission efficiency can be expected.

Further, transmitter <NUM> adjusts the transmission power such that the transmission power falls within a range not exceeding the maximum transmission power for each antenna port, thereby making it possible to prevent transmission with a power lower than the intended power or prevent a signal from being distorted in a case where the remaining amount of the transmission power of transmitter <NUM> is small.

Note that how the transmission power configuration method described above (e.g., Operation Examples <NUM> to <NUM>) is performed may be dependent on implementation of transmitter <NUM>. For example, transmitter <NUM> may apply any method of Operation Examples <NUM> to <NUM> described above and adjust the transmission power, and/or may select any method of Operation Examples <NUM> to <NUM> described above and adjust the transmission power, in accordance with the radio state or the conditions.

In addition, transmitter <NUM> may cancel the configuration of the transmission power reduction in a case where the remaining power of transmitter <NUM> increases, for example, after the transmission power is reduced as in Operation Examples <NUM> to <NUM> described above.

Further, in the present example, the calculation method of the ratio ρPTRS,i indicated in Equation <NUM> is not limited to the above description, and another method may be used.

In the present example, a description will be given of a case where a transmitter, (i.e., mobile station) subjects PT-RS to power boosting and transmits the PT-RS in uplink. Further, in the present example, the base station (receiver) indicates, to the mobile station, whether or not adjustment of the transmission power described in Example is required.

The communication system according to the present example includes mobile station <NUM> (transmitter) and base station <NUM> (receiver). PT-RS is transmitted from mobile station <NUM> to base station <NUM>.

<FIG> is a block diagram illustrating a configuration of mobile station <NUM> (transmitter) according to the present example. In <FIG>, the same components as those of Example <NUM> (<FIG>) are denoted by the same reference numerals, and their descriptions are omitted. Specifically, in addition to the configuration of transmitter <NUM> illustrated in <FIG>, mobile station <NUM> illustrated in <FIG> further includes receiver <NUM>, signal demultiplexer <NUM>, data demodulator <NUM>, and error correction decoder <NUM>. Further, operations of antenna <NUM>, controller <NUM> and error correction encoder <NUM> differ partly from the operations of antenna <NUM>, controller <NUM> and error correction encoder <NUM> illustrated in <FIG>.

Antenna <NUM> radiates the signal to be inputted from transmitter <NUM> toward base station <NUM>. Further, antenna <NUM> receives the signal transmitted from base station <NUM> and outputs the received signal to receiver <NUM>.

Receiver <NUM> applies radio reception processing, such as frequency conversion, to the received signal to be inputted from antenna <NUM>, and outputs the signal after the radio reception processing to signal demultiplexer <NUM>.

Signal demultiplexer <NUM> demultiplexes DCI and a data signal from the signal to be inputted from receiver <NUM>, and outputs the DCI to controller <NUM> and outputs the data signal to data demodulator <NUM>.

Data demodulator <NUM> demodulates the data signal to be inputted from signal demultiplexer <NUM> and outputs the demodulation signal to error correction decoder <NUM>.

Error correction decoder <NUM> decodes the demodulation signal to be inputted from data demodulator <NUM>, extracts an RRC signal from the resultant received data signal, and outputs the RRC signal to controller <NUM>.

Controller <NUM> calculates a Power Headroom (PH) indicating the remaining transmission power of mobile station <NUM>, generates a Power Headroom Report (PHR) to be reported to base station <NUM>, and outputs the PHR to error correction encoder <NUM>. In addition, controller <NUM> determines the transmission power for a transmission signal, such as a data signal and PT-RS, based on the information contained in the DCI to be inputted from signal demultiplexer <NUM> and the information contained in the RRC signal to be inputted from error correction decoder <NUM>. The DCI or RRC signal may include, for example, information indicating whether or not adjustment of the transmission power is required (or information indicating adjustment of the transmission power). Controller <NUM> outputs the determined transmission power information to signal assigner <NUM>.

Error correction encoder <NUM> applies error correction coding to the transmission data signal to be inputted or the PHR to be inputted from controller <NUM> and output the signal resulting from the error correction coding to modulator <NUM>.

<FIG> is a block diagram illustrating a configuration of base station <NUM> (receiver) according to the present example. Note that, in <FIG>, the same components as those of Example <NUM> (<FIG>) are denoted by the same reference numerals, and their descriptions are omitted. Specifically, base station <NUM> illustrated in <FIG> further includes controller <NUM>, error correction encoder <NUM>, modulator <NUM>, signal assigner <NUM>, and transmitter <NUM> in addition to the configuration of receiver <NUM> illustrated in <FIG>. Further, operations of antenna <NUM>, channel estimator <NUM>, and error correction decoder <NUM> differ partly from the operations of antenna <NUM>, channel estimator <NUM>, and error correction decoder <NUM> illustrated in <FIG>.

Error correction decoder <NUM> decodes the demodulation signal to be inputted from data demodulator <NUM> and outputs the resultant received data signal. Further, error correction decoder <NUM> extracts the PHR from the data signal and outputs the PHR to controller <NUM>.

Controller <NUM> determines whether or not mobile station <NUM> is to apply the transmission power control (transmission power adjustment) described in Example <NUM> based on the PHR to be inputted from error correction decoder <NUM>. In addition, controller <NUM> determines, for example, a signal waveform, modulation coding scheme (MCS), and allocation band to be applied to data transmission in mobile station <NUM>. Controller <NUM> generates, based on the determination result and determined content, a DCI (i.e., dynamic signaling) and RRC signal (i.e., higher layer signaling), and outputs the DCI to signal assigner <NUM> and outputs the RRC signal to error correction encoder <NUM>.

Further, controller <NUM> outputs, to channel estimator <NUM>, "information on amplitude of PT-RS and/or the like" indicating whether or not the transmission power control described in Example <NUM> is applied to the signal received from mobile station <NUM>, based on the determination result regarding whether or not the transmission power adjustment is required. The information on amplitude of PT-RS and/or the like may include, for example, information on the amplitude (power) ratio of PT-RS and the data signal after the transmission power adjustment.

Error correction encoder <NUM> applies error correction coding to the RRC signal to be inputted from controller <NUM> and outputs the signal resulting from the error correction coding to modulator <NUM>.

Modulator <NUM> performs modulation processing on the signal to be inputted from error correction encoder <NUM> and outputs the signal after the modulation processing to signal assigner <NUM>.

Signal assigner <NUM> maps the signal to be inputted from modulator <NUM> and the DCI to be inputted from controller <NUM> to the time and frequency domain and outputs the signal after the mapping to transmitter <NUM>.

Transmitter <NUM> applies radio transmission processing, such as frequency conversion using a carrier wave to the signal to be inputted from signal assigner <NUM>, and outputs the signal after the radio transmission processing to antenna <NUM>.

Antenna <NUM> receives the signal transmitted from mobile station <NUM> (see <FIG>) and outputs the received signal to receiver <NUM>. Antenna <NUM> radiates (transmits) the signal to be inputted from transmitter <NUM> toward mobile station <NUM>.

Channel estimator <NUM> performs channel estimation, using DMRS to be inputted from signal demultiplexer <NUM>. At this time, channel estimator <NUM> may perform channel estimation, using PT-RS. When PT-RS is used, channel estimator <NUM> may determine the amplitude (power) ratio between PT-RS and the data signal based on the information on amplitude of PT-RS and/or the like to be inputted from controller <NUM>. Channel estimator <NUM> outputs the channel estimate (channel information) to data demodulator <NUM>. Note that, in a case where no PT-RS is used in channel estimation performed by channel estimator <NUM>, the information on amplitude of PT-RS and/or the like need not be inputted to channel estimator <NUM>.

Next, operations of mobile station <NUM> and base station <NUM> will be described in detail.

Mobile station <NUM> performs a non-coherent transmission or partial coherent transmission, using a high frequency band and a high modulation order in uplink.

Base station <NUM> determines whether or not "the remaining power for transmission with the configured transmission power in a PT-RS port is insufficient," that is, whether or not the transmission power adjustment is required in mobile station <NUM>.

Then, base station <NUM> indicates to mobile station <NUM> to apply the transmission power adjustment described in Example <NUM> in a case where the remaining power for transmitting the signal with the configured transmission power is not sufficient in the PT-RS port. That is, in a case where an indication for transmission power adjustment from base station <NUM> is present, mobile station <NUM> adjusts the transmission power such that the transmission power is less than or equal to the maximum transmission power for each antenna port, as described in Example <NUM>.

Hereinafter, specific Operation Examples <NUM> and <NUM> of mobile station <NUM> and base station <NUM> will be described.

In Operation Example <NUM>, mobile station <NUM> first calculates the transmission power for the data signal, using a parameter and/or the like indicated from base station <NUM>. In addition, mobile station <NUM> determines the transmission power for every RE in a PT-RS port, using the ratio ρPTRS,i indicated in Equation <NUM>. That is, mobile station <NUM> applies power boosting to PT-RS.

Next, mobile station <NUM> calculates a PH. The PH is, for example, a value resulting from subtracting the transmission power for the data signal in all the antenna ports calculated above from the maximum transmission power of the entirety of mobile station <NUM>. Then, mobile station <NUM> reports the calculated PH to base station <NUM> as a PHR.

When the value of the received PHR is less than a threshold value, base station <NUM> determines that there is no sufficient remaining power in the PT-RS port in mobile station <NUM> and indicates adjustment (reduction) of transmission power to mobile station <NUM> as described in Example <NUM>. This indication may be given explicitly or implicitly by an RRC signal or a DCI.

In a case where an indication for transmission power adjustment is present, as described in Example <NUM>, mobile station <NUM> reduces the transmission power for PT-RS or a data signal and transmits the PT-RS and data signal and/or the like after the adjustment to base station <NUM>.

Thus, in Operation Example <NUM>, in a case where the PHR to be calculated using the maximum transmission power of the entirety of mobile station <NUM> and the transmission power for the data signal is less than a threshold value, base station <NUM> indicates adjustment of the transmission power to mobile station <NUM>. This allows a PHR similar to LTE to be used in the transmission power control, so that the configuration to be additionally implemented in mobile station <NUM> and base station <NUM> for transmission power control can be reduced.

Note that, the description has been given of the case where the PHR represents the remaining power in all the antenna ports of mobile station <NUM>, but there is no limitation to this case. For example, the PHR may be a value resulting from subtracting the transmission power for the data signal in a PT-RS port from the maximum transmission power in the PT-RS port. That is, in a case where the PHR to be calculated using the maximum transmission power in the PT-RS port of mobile station <NUM> and the transmission power for the data signal is less than the threshold, adjustment of the transmission power is indicated from base station <NUM> to mobile station <NUM>, transmitter. As a result, base station <NUM> is allowed to know the transmission power state of the PT-RS port in a more detailed manner, so that base station <NUM> can more accurately determine whether or not the transmission power needs to be reduced, and can appropriately provide an indication to mobile station <NUM>.

In Operation Example <NUM>, as in Operation Example <NUM>, mobile station <NUM> first calculates the transmission power for the data, using a parameter and/or the like indicated from base station <NUM>. In addition, mobile station <NUM> determines the transmission power for every RE in a PT-RS port, using the ratio ρPTRS, i indicated in Equation <NUM>. That is, mobile station <NUM> applies power boosting to PT-RS.

Meanwhile, base station <NUM> indicates, to mobile station <NUM>, at least one of a waveform (e.g., CP-OFDM or DFT-S-OFDM), MCS, and band (e.g., the number of PRBs) used for transmission of the data signal.

Mobile station <NUM> determines whether or not to perform the transmission power adjustment as described in Example <NUM>, based on at least one of the waveform, MCS, and the band indicated from base station <NUM>.

For example, in a case where the indicated waveform is "DFT-S-OFDM," as described in Example <NUM>, mobile station <NUM> reduces the transmission power for PT-RS or a data signal and transmits the PT-RS and data signal and/or the like after the adjustment to base station <NUM>. This is because, in a case where the indicated waveform is DFT-S-OFDM (i.e., single carrier waveform), the transmission power is likely to be extremely large because mobile station <NUM> is likely to be positioned on a cell edge.

Further, when the indicated MCS is "MCS of a level lower than the threshold value," mobile station <NUM> reduces the transmission power for PT-RS and the data signal and transmits the PT-RS and data signal after adjustment to base station <NUM> as described in Example <NUM>. This is because, in a case where the indicated MCS is an MCS of a lower level than the MCS within a range of an MCS of a higher level with which PT-RS is transmitted, mobile station <NUM> is likely to be forced to perform transmission to base station <NUM> in a noisy environment, and thus, the transmission power is likely to be high.

Further, when the indicated band is "broader than the threshold value," mobile station <NUM> reduces the transmission power for PT-RS and the data signal and transmits the PT-RS and data signal after adjustment to base station <NUM> as described in Example <NUM>. This is because the transmission power for data increases depending on the allocated band, and therefore, when the indicated band is broader than a certain value, there is a high possibility that the transmission power is large.

In this manner, mobile station <NUM> may determine whether or not to perform transmission power adjustment based on any one of a waveform, MCS and band used for data transmission or a plurality of parameters.

That is, base station <NUM> implicitly indicates, to mobile station <NUM>, the presence or absence of application of transmission power control as described in Example <NUM>, by the indication of at least one of a waveform, MCS, and band. This implicit indication does not require the use of PHRs as described in Operation Example <NUM> in the transmission power control. For this reason, the configuration to be additionally implemented in mobile station <NUM> and base station <NUM> for transmission power control can be reduced.

Operation Examples <NUM> and <NUM> have been described, thus far.

As described above, in the present example, mobile station <NUM> transmits a data signal with a defined transmission power and subjects PT-RS to power boosting, and transmits the PT-RS in non-coherent transmission or partial coherent transmission. In a case where base station <NUM> determines that the remaining power for transmission with the configured transmission power is not sufficient in the PT-RS port of mobile station <NUM>, base station <NUM> indicates, to mobile station <NUM>, adjustment for the transmission power within a range not exceeding the maximum transmission power for each antenna port. Mobile station <NUM> performs a transmission power control in accordance with the instruction of base station <NUM>.

Thus, mobile station <NUM> is capable of transmitting PT-RS with the highest possible transmission power within a range not exceeding the maximum transmission power for each antenna port, in accordance with the remaining power of mobile station <NUM> even in a transmission for which power cannot be adjusted between antenna ports as in non-coherent transmission or partial coherent transmission as in Example <NUM>. Thus, improvement in the transmission speed/transmission efficiency by improving the noise estimation accuracy can be expected in base station <NUM>.

Further, mobile station <NUM> adjusts the transmission power such that the transmission power falls within a range not exceeding the maximum transmission power for each antenna port, thereby making it possible to prevent transmission with a power lower than the intended power and/or prevent a signal from being distorted in a case where the remaining amount of the transmission power of mobile station <NUM> is small.

Further, in the present example, since base station <NUM> indicates transmission power adjustment to mobile station <NUM>, mobile station <NUM> and base station <NUM> can communicate with each other in a state where recognition of the transmission power between mobile station <NUM> and base station <NUM> is the same.

In the present example, a description will be given of a case where a transmitter (i.e., mobile station) subjects PT-RS to power boosting and transmits the PT-RS in uplink. Further, in the present example, the mobile station determines whether or not adjustment of the transmission power is required as described in Example <NUM>.

<FIG> is a block diagram illustrating a configuration of mobile station <NUM> (transmitter) according to the present example. In <FIG>, the same components as those of Example <NUM> (<FIG>) are denoted by the same reference numerals, and their descriptions are omitted. Specifically, operations of controller <NUM> and error correction encoder <NUM> differ partly from the operations of controller <NUM> and error correction encoder <NUM> illustrated in <FIG>.

Controller <NUM> calculates the PH indicating the remaining transmission power of mobile station <NUM>, generates a PHR to be reported to base station <NUM>, and outputs the PHR to error correction encoder <NUM>. Further, controller <NUM> determines whether or not the transmission power control (transmission power adjustment) described in Example <NUM> is to be applied, based on the calculated value of the PH. Then, controller <NUM> determines the transmission power for a transmission signal, such as a data signal and PT-RS, in accordance with the result of determination. Controller <NUM> outputs the determined transmission power information to signal assigner <NUM>.

<FIG> is a block diagram illustrating a configuration of base station <NUM> (receiver) according to the present example. In <FIG>, the same components as those of Example <NUM> (<FIG>) are denoted by the same reference numerals, and their descriptions are omitted. Specifically, base station <NUM> illustrated in <FIG> further includes controller <NUM> in addition to the configuration of receiver <NUM> illustrated in <FIG>. Further, operations of channel estimator <NUM> and error correction decoder <NUM> are different from the operations of channel estimator <NUM> and error correction decoder <NUM> illustrate in <FIG>.

Error correction decoder <NUM> decodes the demodulation signal to be inputted from data demodulator <NUM> and outputs the resultant received data signal. Error correction decoder <NUM> extracts the PHR from the data signal and outputs the PHR to controller <NUM>.

Controller <NUM> determines whether or not mobile station <NUM> applies the transmission power control described in Example <NUM>, based on the PHRs inputted from error correction decoder <NUM>. Further, controller <NUM> outputs, to channel estimator <NUM>, "information on amplitude of PT-RS and/or the like" indicating whether or not the transmission power control described in Example <NUM> is applied to the signal received from mobile station <NUM>, based on the result of determination.

Channel estimator <NUM> performs channel estimation, using DMRS to be inputted from signal demultiplexer <NUM>. At this time, channel estimator <NUM> may perform channel estimation, using PT-RS. When PT-RS is used, channel estimator <NUM> may determine the amplitude (power) ratio between PT-RS and the data signal based on the information on amplitude of PT-RS and/or the like to be inputted from controller <NUM>. Channel estimator <NUM> outputs the channel estimate (channel information) to data demodulator <NUM>.

Note that, in a case where no PT-RS is used in channel estimation by channel estimator <NUM>, the configuration of base station <NUM> may be omitted, and the base station may have the same configuration as receiver <NUM> illustrated in <FIG>.

Mobile station <NUM> performs non-coherent transmission or partial coherent transmission, using a high frequency band and a high modulation order in uplink.

Further, mobile station <NUM> determines whether or not "the remaining power for transmission with the configured transmission power in a PT-RS port is insufficient," that is, whether or not the transmission power adjustment is required.

Then, mobile station <NUM> performs the transmission power adjustment described in Example <NUM> in a case where the remaining transmission power for transmitting the signal with the configured transmission power is not sufficient in the PT-RS port.

Meanwhile, base station <NUM> determines whether or not "the remaining power for transmission with the configured transmission power in a PT-RS port is insufficient" as with mobile station <NUM>. Then, in a case where the remaining power for transmitting a signal with the configured transmission power is not sufficient in the PT-RS port, base station <NUM> determines that the signal is transmitted in mobile station <NUM> after application of the transmission power control described in Example <NUM>. In this case, base station <NUM> performs channel estimation in considering, for example, that the transmission power for PT-RS or the data signal is reduced.

Hereinafter, a specific operation example of mobile station <NUM> and base station <NUM> will be described.

In the operation example, mobile station <NUM> first calculates the transmission power for the data signal, using a parameter and/or the like indicated from base station <NUM>. In addition, mobile station <NUM> determines the transmission power for every RE in the PT-RS port, using the ratio ρPTRS,i indicated in Equation <NUM>. That is, mobile station <NUM> applies power boosting to PT-RS.

Next, mobile station <NUM> calculates a PH. The PH is, for example, a value resulting from subtracting the transmission power for the data signal in all the antenna ports calculated above from the maximum transmission power of the entirety of mobile station <NUM>. Then, mobile station <NUM> reports the calculated PH to base station <NUM> as a PHR.

Further, when the calculated value of PH is less than a threshold value, mobile station <NUM> determines that the remaining power is not sufficient in the PT-RS port of mobile station <NUM>, reduces the transmission power for PT-RS or the data signal, as described in Example <NUM>, and transmits the PT-RS and data signal and/or the like after the adjustment to base station <NUM>.

Likewise, in a case where the value of PHR to be reported from mobile station <NUM> is less than a threshold value, base station <NUM> determines that the transmission power adjustment as described in Example <NUM> has been applied to the received data signal or PT-RS, and performs channel estimation taking the reduction of transmission power into consideration.

Thus, in the operation example, in a case where the PHR to be calculated using the maximum transmission power of the entirety of mobile station <NUM> and the transmission power for the data signal is less than a threshold value, mobile station <NUM> adjusts the transmission power, and base station <NUM> determines that adjustment for transmission power is performed in mobile station <NUM>. This allows a PHR similar to LTE to be used in the transmission power control, so that the configuration to be additionally implemented in mobile station <NUM> and base station <NUM> for transmission power control can be reduced.

Note that, the description has been given of the case where the PHR represents the remaining power in all the antenna ports of mobile station <NUM>, but there is no limitation to this case. For example, the PHR may be a value resulting from subtracting the transmission power for the data signal in a PT-RS port from the transmission power for a data signal in the PT-RS port. That is, in a case where the PHR calculated using the maximum transmission power in the PT-RS port of mobile station <NUM> and the transmission power for the data signal is less than the threshold value, mobile station <NUM> adjusts the transmission power. As a result, mobile station <NUM> and base station <NUM> are allowed to know the transmission power state of the PT-RS port in a more detailed manner, so that mobile station <NUM> and base station <NUM> can more accurately determine whether or not the transmission power needs to be reduced.

The operation example has been described, thus far.

As described above, in the present example, mobile station <NUM> transmits a data signal with a defined transmission power, subjects PT-RS to power boosting and transmits the PT-RS in non-coherent transmission or partial coherent transmission. In this case, in a case where mobile station <NUM> determines that the remaining power for transmission with the configured transmission power is not sufficient in the PT-RS port of mobile station <NUM>, mobile station <NUM> adjusts the transmission power within a range not exceeding the maximum transmission power for each antenna port.

This allows mobile station <NUM> to transmit PT-RS with the highest possible transmission power within a range not exceeding the maximum transmission power for each antenna port, in accordance with the remaining power of mobile station <NUM> even in a transmission for which power cannot be adjusted between antenna ports as in non-coherent transmission or partial coherent transmission as in Example <NUM>. Thus, improvement in the transmission speed/transmission efficiency by improving the noise estimation accuracy in base station <NUM> can be expected.

Further, mobile station <NUM> adjusts the transmission power such that the transmission power falls within a range not exceeding the maximum transmission power for each antenna port, thereby making it possible to prevent transmission with a power lower than the intended power or prevent a signal from being distorted in a case where the remaining amount of the transmission power of mobile station <NUM> is small.

Further, in the present example, mobile station <NUM> determines whether or not to adjust transmission power, thereby enabling configuration of an appropriate transmission power without waiting for an indication of base station <NUM>.

Each example of the present disclosure has been described, thus far.

Claim 1:
A mobile station (<NUM>), comprising:
control means (<NUM>) adapted to determine a transmission power for a phase tracking reference signal, PT-RS, and a data signal within a range not exceeding a maximum transmission power for each antenna port (<NUM>, <NUM>); and
transmission means (<NUM>) adapted to transmit the PT-RS and the data signal with the determined transmission power,
characterized in that
the control means (<NUM>) are adapted to determine whether or not to perform adjustment of the transmission power to be less than or equal to the maximum transmission power for each antenna port (<NUM>, <NUM>), based on at least one of a signal waveform, a modulation coding scheme, and an allocated band indicated by a base station (<NUM>), and
the control means (<NUM>) are adapted to determine to perform the adjustment of the transmission power in a case where a level of the modulation coding scheme is lower than a threshold value.