Base station, receiving method and integrated circuit

Abstract

To appropriately control transmission power at the PT-RS port. In a transmitter (100), a control unit (101) determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding the maximum transmission power for each antenna port. A transmitting unit (105) then transmits the phase tracking reference signal and the data signal at the transmission power determined by the control unit (101).

Description

[Technical field]

[0001] The present disclosure relates to a transmitter and a transmission method. [Background technology]

[0002] A communication system called the fifth generation mobile communication system (5G) is being considered. In 5G, it is being considered to flexibly provide functions for each use case that requires an increase in communication traffic, an increase in the number of connected terminals, high reliability, and low latency. There are three representative use cases: enhanced mobile broadband (eMBB), massive machine type communications / multiple connections (mMTC), and ultra reliable and low latency communications (URLLC). The 3rd Generation Partnership Project (3GPP), an international standardization organization, is considering the advancement of communication systems from the perspectives of both the advancement of LTE systems and New RAT (Radio Access Technology) (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] RP-161596, "Revision of SI: Study on New Radio Access Technology", NTT DOCOMO, September 2016 [Non-Patent Document 2] R1-1612335, "On phase noise effects", Ericsson, November 2016 [Non-Patent Document 3] 3GPP TR 38.214 V15.0.0, "NR Physical layer procedure for data (Release 15)" (2017-12) [Non-Patent Document 4] R1-1611665, "Multi-panel based UL MIMO transmission", Huawei, HiSilicon, November 2016 [Non-Patent Document 5] 3GPP TR 38.211 V15.0.0, "NR Physical channels and modulation (Release 15)" (2017-12) Summary of the Invention [Problem to be solved by the invention]

[0004] In the New RAT, for example, a signal with a frequency of 6 GHz or more is used as a carrier wave. In particular, when a high frequency band and a high modulation order are used, error rate performance is degraded by CPE (Common Phase Error) or ICI (Inter-carrier Interference) caused by phase noise of a local oscillator (see, for example, Non-Patent Document 2). Therefore, in the New RAT, it is considered that the receiver performs CPE correction or ICI correction (hereinafter, sometimes referred to as "CPE / ICI correction") using a phase tracking reference signal (PT-RS) in addition to channel equalization.

[0005] However, further study is required regarding the transmission power control in the antenna port that transmits the PT-RS (hereinafter, also referred to as the "PT-RS port").

[0006] One aspect of the present disclosure contributes to providing a transmitter and a transmission method capable of appropriately controlling transmission power at a PT-RS port. [Means for solving the problem]

[0007] A transmitter according to one embodiment of the present disclosure includes a control circuit that determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding a maximum transmission power for each antenna port, and a transmission circuit that transmits the PT-RS and the data signal at the determined transmission power.

[0008] A transmission method according to one embodiment of the present disclosure determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding the maximum transmission power for each antenna port, and transmits the PT-RS and the data signal at the determined transmission power.

[0009] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0010] According to one embodiment of the present disclosure, transmission power control can be appropriately performed at the PT-RS port.

[0011] Further advantages and benefits of certain aspects of the present disclosure will become apparent from the specification and drawings, in which such advantages and / or benefits are provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of which are provided to obtain one or more identical features. [Brief description of the drawings]

[0012] [Figure 1] A diagram showing an example of mapping of DMRS and PT-RS in MIMO. [Diagram 2] A diagram showing an example of power boosting [Diagram 3] FIG. 1 shows an example of non-coherent transmission and coherent transmission. [Figure 4] A diagram showing an example of PT-RS transmission in non-coherent transmission. [Diagram 5] FIG. 1 is a block diagram showing a configuration of a part of a transmitter according to a first embodiment. [Figure 6] FIG. 1 is a block diagram showing a configuration of a transmitter according to a first embodiment. [Figure 7] FIG. 1 is a block diagram showing a configuration of a receiver according to a first embodiment. [Figure 8] A flowchart showing the operation of the transmitter according to the first embodiment. [Figure 9] FIG. 1 is a diagram showing an example of transmission power adjustment according to an operation example 1 of the first embodiment; [Figure 10] FIG. 13 is a diagram showing an example of transmission power adjustment according to an operation example 2 of the first embodiment; [Figure 11] FIG. 13 is a diagram showing an example of transmission power adjustment according to an operation example 3 of the first embodiment; [Figure 12] FIG. 13 is a diagram showing an example of transmission power adjustment according to an operation example 4 of the first embodiment; [Figure 13] FIG. 13 is a diagram showing an example of transmission power adjustment according to an operation example 5 of the first embodiment. [Figure 14] FIG. 11 is a block diagram showing a configuration example of a transmitter according to a second embodiment. [Figure 15] FIG. 11 is a block diagram showing a configuration example of a receiver according to a second embodiment. [Figure 16] FIG. 11 is a block diagram showing a configuration example of a transmitter according to a third embodiment. [Figure 17] FIG. 11 is a block diagram showing a configuration example of a receiver according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0014] [Power Boosting] When the number of antenna ports (PT-RS ports) transmitting PT-RS is different from the number of antenna ports (DMRS ports) transmitting data and DMRS, the transmission power per RE (Resource Element) of PT-RS on one antenna port may be set to be larger than the transmission power per RE of data on one antenna port transmitted and received between the same base station and mobile station. This transmission power control for PT-RS may be called "power boosting". Power boosting of PT-RS is expected to improve the reception accuracy and CPE / ICI estimation accuracy of PT-RS, and to improve transmission speed / transmission efficiency.

[0015] In addition, it is assumed that NR codebook-based uplink supports full-coherent transmission, non-coherent transmission, and partial-coherent transmission. Among these, in non-coherent transmission and partial coherent transmission, there is an opinion that power boosting of PT-RS is difficult because an upper limit (maximum transmission power) of the transmission power is set for each antenna port. However, in order to estimate CPE / ICI with higher accuracy, the PT-RS should be power boosted as much as possible in any transmission method. Therefore, it is necessary to consider a method of power boosting the PT-RS in non-coherent transmission or partial coherent transmission.

[0016] [PT-RS] The higher the frequency band to which a signal is assigned, or the higher the modulation level used in the signal, the greater the impact of CPE / ICI on error rate performance. Therefore, as mentioned above, when using a high frequency band and a high order modulation level, the receiver is being considered to perform CPE / ICI compensation using PT-RS in addition to channel equalization.

[0017] In order to track the CPE / ICI that varies randomly over time, the PT-RS is mapped at a higher density on the time axis compared to a reference signal for channel estimation (demodulation) (DMRS: Demodulation Reference Signal). Specifically, the PT-RS is assumed to be mapped at a density of, for example, one symbol per symbol, one symbol per two adjacent symbols, or one symbol per four adjacent symbols. In addition, since the CPE / ICI has a characteristic that there is little variation between subcarriers, the PT-RS is mapped at a relatively low density in the frequency domain. Specifically, the PT-RS is assumed to be mapped at a density of, for example, one per RB (Resource Block) (e.g., one subcarrier), one per two adjacent RBs, or one per four adjacent RBs.

[0018] According to the 3GPP RAN1#88 agreement on PT-RS, the PT-RS is used between a base station (BS, eNB, gNB) and a mobile station (terminal, UE) notified by the base station through higher layer signaling (e.g., RRC (Radio Resource Control) signaling). It is also assumed that the placement density of the PT-RS in the time domain and frequency domain can be flexibly changed depending on the modulation level or bandwidth used between the base station and the mobile station.

[0019] Methods for a mobile station to determine the placement density of PT-RS are also under consideration. One method is that the placement density of PT-RS is notified from the base station by a control signal dedicated to PT-RS (e.g., DCI (Downlink Control Information) or an RRC signal, etc.) (explicit indication). Another method is that a correspondence relationship between the placement density of PT-RS and other parameters (e.g., modulation multi-level number or bandwidth, etc.) is determined in advance, and the mobile station determines the placement density of PT-RS by checking the other parameters notified by DCI during communication against the correspondence relationship (implicit indication). Note that methods other than these may also be used.

[0020] On the other hand, the DMRS used for channel estimation is mapped more densely in the frequency domain and less densely in the time domain compared to the PT-RS, because the channel characteristics change significantly in the frequency domain and change less significantly in the time domain than the phase noise. Furthermore, the New RAT is expected to introduce front-loaded DMRS, which is placed at the front of the slot, to advance the timing of data demodulation.

[0021] In addition, it is being considered that the PT-RS will be placed on the same antenna port as a certain DMRS (this port may be called the PT-RS port), and that the same precoding as that for the DMRS port will be applied to the PT-RS. Therefore, the receiver may use the PT-RS for channel estimation in the same way as the DMRS.

[0022] PT-RS may also be defined as a part of DMRS. In this case, the DMRS used as PT-RS is mapped more densely in the time domain and less densely in the frequency domain than other DMRS. Also, the reference signal used to correct CPE / ICI caused by phase noise may be called by a name other than "PT-RS".

[0023] In addition, the New RAT is expected to use MIMO (Multiple Input Multiple Output), which means that a base station and one or more mobile stations in a cell that the base station configures can transmit and receive using multiple antenna ports that support different precoding using the same time-frequency resources.

[0024] The base station and the mobile station each have a limit on their maximum transmission power. For this reason, it is assumed that the total transmission power of the multiple antenna ports used for data transmission will not exceed the maximum transmission power. In addition, it is basically assumed that the transmission power of data from each antenna port is equal. Therefore, for example, when transmitting data or a reference signal using one antenna port, the transmission power per antenna port is considered to be n times larger in the former case than in the latter case.

[0025] The PT-RS is transmitted and received between a base station and each mobile station in a cell that the base station configures. Here, in a group of antenna ports (which may be called a DMRS port group) that share a local oscillator of a transmitter (a base station in the downlink, and a mobile station in the uplink), the CPE / ICI value is likely to be the same. For this reason, it is assumed that the PT-RS is transmitted from any one of the antenna ports in this group.

[0026] Furthermore, it is considered that the PT-RS transmitted to and received from one mobile station is orthogonally multiplexed in time / frequency / space with respect to data. Therefore, when the PT-RS is transmitted from one antenna port (a certain RE), nothing is transmitted from the other antenna ports used by the mobile station in the RE. In other words, in a certain RE, power is used for the PT-RS from one antenna port, and no power is used (nothing is transmitted) from the other antenna ports.

[0027] In the New RAT, a transmission power control method known as "PT-RS power boosting" is being considered, which utilizes the power of resources not used by other antenna ports and increases the transmission power per RE of one antenna port of PT-RS by the amount of the power of these unused resources, making it greater than the transmission power per RE of one antenna port of data.

[0028] As an example, Fig. 1 shows a mapping example of DMRS, PT-RS, and data in MIMO. In the RE (symbol x subcarrier) in the bottom subcarrier in Fig. 1, the PT-RS is transmitted at antenna port 1000. At this time, in the same RE group as the RE group in which the PT-RS is transmitted at antenna port 1000 (i.e., the bottom subcarrier), nothing is transmitted (blank) at antenna port 1001.

[0029] 2 shows an example of transmission power allocation in the REs of antenna ports 1000 and 1001 before and after power boosting the PT-RS. In the example shown in FIG. 2, antenna port 1000 adds (power boosts) the power of the REs unused in antenna port 1001 to the PT-RS and transmits the PT-RS. Therefore, as shown in FIG. 2, after power boosting of the PT-RS, the transmission power of not only the RE in which the PT-RS is transmitted but also the entire antenna port 1000 becomes greater than the transmission power of antenna port 1001.

[0030] According to the description of uplink PT-RS power boosting in Non-Patent Document 3, when a PT-RS is transmitted from one antenna port (one PT-RS port) in the uplink, the ratio indicating "how many times the data power is compared with the PT-RS power" per 1 RE in the PT-RS port is defined as ρ PTRS,i and is calculated by the following formula:

number

[0031] In formula (1), n layer PUSCH indicates the number of layers of transmission data set in the base station (i.e., receiver).

[0032] [Transmitter precoding] In uplink transmission of the New RAT, two transmission methods are assumed: codebook based UL transmission and non-codebook based UL transmission (see, for example, Non-Patent Document 3). Furthermore, in codebook based transmission, the number of precoding matrices that can be used varies depending on the type of coherent transmission that the mobile station can support. It is assumed that the types of mobile station capabilities (UE capabilities) related to coherent transmission can be divided into the following three types. fullAndPartialAndNonCoherent partialAndNonCoherent Non-Coherent

[0033] The first, "fullAndPartialAndNonCoherent", indicates that there is a capability to support all types of coherent transmission. The second, "partialAndNonCoherent", indicates that there is a capability to support partial coherent transmission and noncoherent transmission. The third, "Non-Coherent", indicates that there is a capability to support only noncoherent transmission.

[0034] Here, "non-coherent transmission" refers to a transmission method in which independent precoding is applied to different antenna panels in a transmitter equipped with multiple non-uniform antenna panels (see, for example, Non-Patent Document 4). In this case, data on different layers is transmitted from different panels. "Coherent transmission" refers to a transmission method in which data on all layers can be transmitted from all antenna panels in a transmitter equipped with uniform antenna panels. Also, "partially coherent transmission" refers to a transmission method in which data of some layer groups is transmitted from some antenna panel groups, and data of other layers is transmitted from the remaining antenna panel groups.

[0035] Table 1 shows precoding matrices that are assumed to be usable when the number of layers is 2 and the number of antenna ports is 2 (see, for example, Non-Patent Document 5). In coherent transmission, all matrices in Table 1 can be used, whereas in non-coherent transmission, it is assumed that only the leftmost matrix in Table 1 can be used. [Table 1]

[0036] Fig. 3 shows examples of non-coherent transmission and coherent transmission. As shown in Fig. 3, in the case of non-coherent transmission, data of each layer (Layer #1, #2) is transmitted from an independent panel by a precoding matrix.

[0037] FIG. 4 shows an example of transmission when PT-RS is transmitted in non-coherent transmission. As described above, PT-RS may be transmitted by some antenna ports (Port #1 in FIG. 4). Therefore, in the case of non-coherent transmission (or partially coherent transmission), the transmission power of the panel transmitting PT-RS (the panel corresponding to Port #1 in FIG. 4) may be greater than the transmission power of other panels (the panel corresponding to Port #2 in FIG. 4). Furthermore, when the PT-RS shown in FIG. 4 is power boosted, the transmission power of the panel may exceed the power that can be transmitted as a performance. As a result, the signal including the PT-RS may be distorted, or the PT-RS may not be transmitted with the intended power, which may deteriorate the CPE / ICI estimation accuracy and degrade the data transmission efficiency.

[0038] Therefore, in one aspect of the present disclosure, a method is described for appropriately performing transmission power control (including power boosting) on ​​a PT-RS in non-coherent transmission or partially coherent transmission, thereby improving CPE / ICI estimation accuracy and improving data transmission efficiency.

[0039] [Signal waveform] In the New RAT, it is assumed that the CP-OFDM (Cyclic Prefix - Orthogonal Frequency Division Multiplexing) method will be used in the downlink (from the base station to the mobile station, downlink). On the other hand, both the CP-OFDM method and the DFT-S-OFDM (Descrete Fourier Transform - Spread OFDM) method are being considered for the uplink (from the mobile station to the base station, uplink), and it is assumed that the communication method will be switched according to the communication environment.

[0040] [PHR] In the New RAT, it is assumed that the transmission of transmission power headroom information (PHR: Power Headroom Report) similar to that of LTE will be transmitted in uplink transmission. That is, the mobile station, which is the transmitter, reports to the base station as the PHR, the value obtained by subtracting the actual data transmission power from the maximum transmission power of the mobile station. However, the PHR value is not the transmission power headroom for each antenna port, but the value for the entire mobile station, combining all antenna ports.

[0041] (Embodiment 1) [Communication system overview] The communication system according to the present embodiment includes a transmitter 100 and a receiver 200. That is, in the uplink, the transmitter is a mobile station and the receiver is a base station. Also, in the downlink, the transmitter is a base station and the receiver is a mobile station.

[0042] Fig. 5 is a block diagram showing a configuration of a part of transmitter 100 according to this embodiment. In transmitter 100 shown in Fig. 5, control unit 101 determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding the maximum transmission power for each antenna port, and transmission unit 105 transmits the PT-RS and the data signal with the determined transmission power.

[0043] [Transmitter configuration] Fig. 6 is a block diagram showing a configuration of transmitter 100 according to this embodiment. In Fig. 6, transmitter 100 has a control unit 101, an error correction coding unit 102, a modulation unit 103, a signal allocation unit 104, a transmission unit 105, and an antenna 106.

[0044] Information such as the transmission power margin of the transmitter 100 is input to the control unit 101. Based on this information, the control unit 101 determines the transmission power of data, PT-RS, etc. Then, the control unit 101 outputs transmission power information indicating the determined transmission power to the signal allocation unit 104.

[0045] The error correction coding section 102 performs error correction coding on the input transmission data signal, and outputs the data signal after error correction coding to the modulation section 103 .

[0046] The modulation section 103 performs modulation processing on the signal input from the error correction coding section 102 and outputs the modulated data signal to the signal allocation section 104 .

[0047] Signal allocating section 104 maps the DMRS, the PT-RS, or the data signal input from modulating section 103 into the time-frequency domain and outputs the mapped signal to transmitting section 105. At this time, signal allocating section 104 sets the transmission power of each signal based on transmission power information input from control section 101.

[0048] The transmitting section 105 performs radio transmission processing such as frequency conversion using a carrier wave on the signal input from the signal allocating section 104, and outputs the signal after the radio transmission processing to the antenna .

[0049] Antenna 106 radiates the signal input from transmitter 105 toward receiver 200 .

[0050] [Receiver configuration] Fig. 7 is a block diagram showing an example of the configuration of receiver 200 according to this embodiment. In Fig. 7, receiver 200 has antenna 201, receiving unit 202, signal separating unit 203, channel estimating unit 204, CPE / ICI estimating unit 205, data demodulating unit 206, and error correction decoding unit 207.

[0051] The antenna 201 receives a signal transmitted from the transmitter 100 (see FIG. 6), and outputs the received signal to the receiving unit 202.

[0052] Receiving section 202 performs radio reception processing such as frequency conversion on the received signal input from antenna 201 , and outputs the signal after radio reception processing to signal separating section 203 .

[0053] Signal separation section 203 identifies and separates the time-frequency domain positions to which the data signal, DMRS, and PT-RS are mapped in the signal input from receiving section 202. Of the separated signals, signal separation section 203 outputs the data signal to data demodulation section 206, outputs the DMRS to channel estimation section 204 and CPE / ICI estimation section 205, and outputs the PT-RS to channel estimation section 204 and CPE / ICI estimation section 205.

[0054] The channel estimation unit 204 estimates a channel using the DMRS input from the signal separation unit 203, and outputs a channel estimation value (channel information) to the data demodulation unit 206. Note that the channel estimation unit 204 may estimate a channel using the PT-RS input from the signal separation unit 203. In this case, the channel estimation unit 204 may perform channel estimation based on the PT-RS using information on the amplitude of the input PT-RS (for example, the amplitude (power) ratio between the PT-RS and a data signal transmitted from the transmitter 100).

[0055] The CPE / ICI estimation unit 205 estimates the CPE / ICI using the PT-RS and DMRS input from the signal separation unit 203 , and outputs the CPE / ICI estimated value to the data demodulation unit 206 .

[0056] Data demodulation section 206 demodulates the data signal input from signal separation section 203, using the channel estimation value input from channel estimator 204 and the CPE / ICI estimation value input from CPE / ICI estimation section 205. Data demodulation section 206 outputs the demodulated signal to error correction decoding section 207.

[0057] The error correction decoder 207 decodes the demodulated signal input from the data demodulator 206, and outputs the resulting received data signal.

[0058] [Operation of transmitter 100 and receiver 200] Next, the operation of the transmitter 100 and the receiver 200 will be described in detail.

[0059] FIG. 8 is a flowchart showing the flow of processing in the transmitter 100.

[0060] It should be noted that the transmitter 100 performs, for example, non-coherent transmission or partially coherent transmission.

[0061] First, the transmitter 100 (control unit 101) sets the transmission power of the PT-RS and the data signal (DMRS) (ST101). At this time, the transmitter 100 may set a specified transmission power for the data signal and apply power boosting to the PT-RS.

[0062] Next, the transmitter 100 (control unit 101) determines whether the set transmission power needs to be adjusted (ST102). For example, when the antenna port (PT-RS port) from which the PT-RS is transmitted does not have sufficient remaining power to transmit signals (PT-RS and data signals) at the transmission power set in ST101, the transmitter 100 determines that the transmission power needs to be adjusted.

[0063] If adjustment of the transmission power is not necessary (ST102: NO), transmitter 100 proceeds to the process in ST104.

[0064] On the other hand, if the transmission power needs to be adjusted (ST102: YES), transmitter 100 (control unit 101) adjusts the transmission power so that it falls within the maximum transmission power for each antenna port (i.e., below the maximum transmission power) (ST103). In other words, when there is insufficient remaining power for transmitting a signal at the set transmission power, transmitter 100 reduces the transmission power so that it falls within the maximum transmission power for each antenna port.

[0065] Then, transmitter 100 (transmitting section 105) transmits signals from each antenna port with the transmission power set in ST 101 or the transmission power adjusted in ST 103 (ST 104).

[0066] Next, operation examples 1 to 5 of transmission power adjustment (ST103 in FIG. 8) by transmitter 100 when there is insufficient remaining power for transmitting a signal at the set transmission power will be described in detail.

[0067] In the following, as an example, a case will be described in which data (DMRS) and PT-RS are assigned to antenna port 1000, and data (DMRS) is assigned to antenna port 1001. Furthermore, the transmitter 100 uses, for example, a high frequency band and a high-order modulation level, and applies power boosting to the PT-RS in non-coherent transmission or partially coherent transmission.

[0068] In addition, the left side of Figures 9 to 13 show the transmission power for each RE set for data and PT-RS at each antenna port 1000, 1001 before the transmission power is reduced (before adjustment), and the right side of Figures 9 to 13 show the transmission power for each RE for data and PT-RS at each antenna port 1000, 1001 after the transmission power is reduced (after adjustment).

[0069] <Example 1> The transmitter 100 first defines a ratio ρ 1 that indicates how many times the power of the data is compared with the power of the PT-RS per RE at the i-th PT-RS port. PTRS,i and is calculated using the following formula:

number

[0070] Here, N PTRS indicates the number of PT-RS ports configured with the TX in the transmitter 100. DMRS PTRS,i indicates the number of DMRS ports that belong 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 shown in FIG. 9, NPTRS = 1, and n DMRS PTRS,i =2.

[0071] Note that the transmitter 100 uses equation (1) instead of equation (2) to calculate the ratio ρ PTRS,i may be calculated.

[0072] Next, the transmitter 100 reduces (adjusts) the transmission power of the signal so that it falls within the maximum transmission power per antenna port.

[0073] FIG. 9 shows an example of transmission power adjustment in the first operation example.

[0074] As shown in FIG. 9, the transmitter 100 uses the power ratio ρ PTRS,i While maintaining the same before and after the adjustment, the transmitter 100 reduces the transmission power of the PT-RS and data signals transmitted from all antenna ports 1000, 1001. That is, the transmitter 100 reduces the transmission power of the PT-RS and data signals from antenna port 1000, which is the PT-RS port, and also reduces the transmission power of the data signal from the other antenna port 1001.

[0075] As a result, the data transmission power is constant (the same) between the antenna ports even after the transmission power is adjusted, so that the transmitter 100 can transmit data from all the antenna ports fairly.

[0076] Furthermore, since the ratio of the transmission power of data to that of PT-RS does not change before and after the adjustment of the transmission power, there is no effect on the reception process that uses this ratio.

[0077] In addition, when receiver 200 receives information that "there is insufficient spare power at the PT-RS port of transmitter 100 for transmission at the set transmission power," receiver 200 may estimate the amplitude (power) ratio between PT-RS and data from this information, and perform channel estimation using the PT-RS based on the estimated ratio.

[0078] <Example 2> FIG. 10 shows an example of transmission power adjustment in the second operation example.

[0079] As shown in FIG. 10, the transmitter 100 uses a power ratio ρ PTRS,i The transmitter 100 reduces the transmission power of the PT-RS and data signals transmitted at the PT-RS port (antenna port 1000) while maintaining the same before and after the adjustment. That is, the transmitter 100 reduces the transmission power at the PT-RS port, but does not reduce the transmission power at the antenna port 1001 other than the PT-RS port.

[0080] As a result, at the PT-RS port, the ratio of transmission power between data and PT-RS does not change before and after the adjustment of the transmission power, so there is no effect on the reception process which uses this ratio.

[0081] Furthermore, since the data transmission power is not reduced for antenna ports other than the PT-RS port, deterioration of the data reception accuracy in receiver 200 can be prevented.

[0082] <Example 3> FIG. 11 shows an example of transmission power adjustment in the third operation example.

[0083] 11, the transmitter 100 reduces the transmission power of data at the PT-RS port (antenna port 1000) while maintaining the transmission power of the PT-RS without reducing it. That is, in the operation example 3, the transmitter 100 reduces the power ratio ρ PTRS,i does not maintain.

[0084] As a result, the transmission power of the PT-RS is not reduced at the PT-RS port, so that deterioration of the reception accuracy of the PT-RS at receiver 200 can be prevented.

[0085] <Example 4> FIG. 12 shows an example of transmission power adjustment in the fourth operation example.

[0086] 12, the transmitter 100 reduces the transmission power at the PT-RS port (antenna port 1000) by not transmitting anything in some of the REs to which data is mapped. That is, in operation example 4, the transmitter 100 reduces the transmission power at the PT-RS port in some of the REs to which data signals are mapped, and maintains the transmission power of the PT-RS and data signals mapped to other REs without reducing it.

[0087] As a result, in the PT-RS port, the transmission power of the PT-RS and data in the RE actually transmitted from the transmitter 100 is not reduced, so that deterioration of the reception accuracy of the PT-RS and data in the receiver 200 can be prevented.

[0088] <Example 5> FIG. 13 shows an example of transmission power adjustment in the fifth operation example.

[0089] 13, the transmitter 100 reduces the transmission power of the PT-RS to the transmission power of the data signal at the PT-RS port (antenna port 1000). That is, the transmitter 100 reduces the transmission power of the PT-RS at the PT-RS port, but does not reduce the transmission power of the data signal.

[0090] That is, as shown in FIG. 13, the transmitter 100 uses a power ratio ρ PTRS,i = 1, and transmit the PT-RS with the same "power per antenna port per RE" as the data. In other words, the transmitter 100 cancels power boosting of the PT-RS.

[0091] This prevents a decrease in the transmission power of the data signal, thereby preventing deterioration in the reception accuracy of data at receiver 200.

[0092] 13, a case has been described in which the transmission power of the PT-RS is reduced to the transmission power of the data signal, but this is not limiting, and the transmitter 100 may reduce the transmission power of the PT-RS so as not to exceed the maximum transmission power of the PT-RS port. In other words, the transmission power of the PT-RS after adjustment may be greater or less than the transmission power of the data signal.

[0093] Operation examples 1 to 5 have been described above.

[0094] Thus, in this embodiment, when non-coherent transmission or partially coherent transmission is performed, the transmitter 100 transmits a data signal at a specified transmission power and transmits the PT-RS with power boosting. At this time, if the PT-RS port does not have enough spare power to transmit at the set transmission power, the transmitter 100 adjusts the transmission power so that it falls within the maximum transmission power for each antenna port.

[0095] That is, the transmitter 100 sets the transmission power of the PT-RS and the signal (such as data) transmitted simultaneously with the PT-RS within a range not exceeding the maximum transmission power of each antenna port. This transmission power setting may include application and cancellation of power boosting of the PT-RS. Furthermore, when the transmission power set in the PT-RS port exceeds the maximum transmission power of the PT-RS port, the transmitter 100 adjusts the transmission power to be equal to or less than the maximum transmission power of each antenna port.

[0096] As a result, even in transmission in which power cannot be adjusted between antenna ports, such as non-coherent transmission or partially coherent transmission, transmitter 100 can transmit PT-RS at as high a power as possible within a range that does not exceed the maximum transmission power for each antenna port, according to the remaining transmission power of transmitter 100. As a result, noise estimation accuracy can be improved in receiver 200, and improvements in transmission speed / transmission efficiency can be expected.

[0097] In addition, by adjusting the transmission power so that it falls within the maximum transmission power for each antenna port, the transmitter 100 can prevent signals from being transmitted at a lower power than intended or from being distorted when the transmitter 100 has little spare transmission power.

[0098] How to perform the above-mentioned transmission power setting method (for example, operation examples 1 to 5) may depend on the implementation of the transmitter 100. For example, the transmitter 100 may adjust the transmission power by applying any of the above-mentioned operation examples 1 to 5, or may select any of the above-mentioned operation examples 1 to 5 to adjust the transmission power depending on the radio situation or conditions.

[0099] Furthermore, if the remaining power of the transmitter 100 becomes large after the transmission power has been reduced as in the above-described operation examples 1 to 5, the transmitter 100 may cancel the setting of the reduction in the transmission power.

[0100] In the present embodiment, the ratio ρ PTRS,i The calculation method is not limited to the above, and other methods may be used.

[0101] (Embodiment 2) In this embodiment, a case will be described in which a transmitter (i.e., a mobile station) transmits a PT-RS with power boosting in the uplink. Also, in this embodiment, a base station (receiver) instructs a mobile station on whether or not to adjust the transmission power described in the first embodiment.

[0102] [Communication system overview] The communication system according to this embodiment includes a mobile station 300 (transmitter) and a base station 400 (receiver). The PT-RS is transmitted from the mobile station 300 to the base station 400.

[0103] [Mobile station configuration] Fig. 14 is a block diagram showing the configuration of a mobile station 300 (transmitter) according to this embodiment. In Fig. 14, the same components as those in the first embodiment (Fig. 6) are given the same reference numerals, and the description thereof will be omitted. Specifically, the mobile station 300 shown in Fig. 14 newly includes a receiving unit 302, a signal separating unit 303, a data demodulating unit 304, and an error correction decoding unit 305 in addition to the configuration of the transmitter 100 shown in Fig. 6. Also, the operations of the antenna 301, the control unit 306, and the error correction coding unit 307 are partially different from the operations of the antenna 106, the control unit 101, and the error correction coding unit 102 shown in Fig. 6.

[0104] Antenna 301 radiates the signal input from transmitting section 105 toward base station 400. Antenna 301 also receives a signal transmitted from base station 400, and outputs the received signal to receiving section 302.

[0105] The receiving section 302 performs radio reception processing such as frequency conversion on the received signal input from the antenna 301 , and outputs the signal after the radio reception processing to the signal separating section 303 .

[0106] The signal separating unit 303 separates the signal input from the receiving unit 302 into a DCI and a data signal, outputs the DCI to a control unit 306 , and outputs the data signal to a data demodulating unit 304 .

[0107] The data demodulation unit 304 demodulates the data signal input from the signal separation unit 303 , and outputs the demodulated signal to the error correction decoding unit 305 .

[0108] The error correction decoding unit 305 decodes the demodulated signal input from the data demodulation unit 304 , extracts the RRC signal from the resulting received data signal, and outputs it to the control unit 306 .

[0109] The control unit 306 calculates a power headroom (PH) indicating the transmission power margin of the mobile station 300, generates a power headroom report (PHR) to be reported to the base station 400, and outputs the generated report to the error correction coding unit 307. The control unit 306 also determines the transmission power of transmission signals such as the data signal and the PT-RS based on information included in the DCI input from the signal separation unit 303 and information included in the RRC signal input from the error correction decoding unit 305. The DCI or the RRC signal may include, for example, information indicating whether or not the transmission power needs to be adjusted (or information instructing the adjustment of the transmission power). The control unit 306 outputs the determined transmission power information to the signal allocation unit 104.

[0110] The error correction coding section 307 performs error correction coding on the input transmission data signal or the PHR input from the control section 306 , and outputs the signal after error correction coding to the modulation section 103 .

[0111] [Base station configuration] Fig. 15 is a block diagram showing the configuration of base station 400 (receiver) according to this embodiment. In Fig. 15, the same components as those in embodiment 1 (Fig. 7) are given the same reference numerals, and the description thereof will be omitted. Specifically, base station 400 shown in Fig. 15 newly includes control section 402, error correction coding section 403, modulation section 404, signal allocation section 405, and transmission section 406 in addition to the configuration of receiver 200 shown in Fig. 7. Also, the operations of antenna 407, channel estimation section 408, and error correction decoding section 401 are partially different from the operations of antenna 201, channel estimation section 204, and error correction decoding section 207 shown in Fig. 7.

[0112] Error correction decoding section 401 decodes the demodulated signal input from data demodulation section 206, and outputs the obtained received data signal. Error correction decoding section 401 also extracts the PHR from the data signal, and outputs the PHR to control section 402.

[0113] The control unit 402 judges whether or not the mobile station 300 should apply the transmission power control (transmission power adjustment) described in the first embodiment, based on the PHR input from the error correction decoding unit 401. Furthermore, the control unit 402 determines, for example, a signal waveform, a modulation scheme (MCS), and an allocation band to be applied to data transmission in the mobile station 300. The control unit 402 generates DCI (i.e., dynamic signaling) and an RRC signal (i.e., higher layer signaling) based on the judgment result and the determined content, outputs the DCI to the signal allocation unit 405, and outputs the RRC signal to the error correction coding unit 403.

[0114] Furthermore, based on the result of the determination as to whether or not transmission power adjustment is required, the control unit 402 outputs "amplitude information of PT-RS, etc." indicating whether or not the transmission power control described in the first embodiment is applied to the signal received from the mobile station 300, to the channel estimation unit 408. The amplitude information of PT-RS, etc. may include, for example, information on the amplitude (power) ratio between the PT-RS and the data signal after the transmission power adjustment.

[0115] The error correction coding section 403 performs error correction coding on the RRC signal input from the control section 402 , and outputs the signal after error correction coding to the modulation section 404 .

[0116] The modulation section 404 performs modulation processing on the signal input from the error correction coding section 403 and outputs the modulated signal to the signal allocation section 405 .

[0117] The signal allocation section 405 maps the signal inputted from the modulation section 404 and the DCI inputted from the control section 402 into the time-frequency domain, and outputs the mapped signal to the transmission section 406 .

[0118] The transmitting unit 406 performs radio transmission processing such as frequency conversion using a carrier wave on the signal input from the signal allocating unit 405 , and outputs the signal after radio transmission processing to the antenna 407 .

[0119] Antenna 407 receives a signal transmitted from mobile station 300 (see FIG. 14) and outputs the received signal to receiving section 202. In addition, antenna 407 radiates (transmits) a signal input from transmitting section 406 toward mobile station 300.

[0120] The channel estimation unit 408 estimates the channel using the DMRS input from the signal separation unit 203. At this time, the channel estimation unit 408 may estimate the channel using the PT-RS. When the PT-RS is used, the channel estimation unit 408 may determine the amplitude (power) ratio between the PT-RS and the data signal based on the amplitude information of the PT-RS etc. input from the control unit 402. The channel estimation unit 408 outputs the channel estimation value (channel information) to the data demodulation unit 206. Note that, when the PT-RS is not used in the channel estimation by the channel estimation unit 408, the amplitude information of the PT-RS etc. does not need to be input to the channel estimation unit 408.

[0121] [Operation of Mobile Station 300 and Base Station 400] Next, the operations of the mobile station 300 and the base station 400 will be described in detail.

[0122] In the uplink, the mobile station 300 performs non-coherent transmission or partially coherent transmission using a high frequency band and a high-order modulation level.

[0123] The base station 400 determines whether or not the mobile station 300 has insufficient remaining power for transmission at the set transmission power in the PT-RS port, that is, whether or not a transmission power adjustment is necessary.

[0124] Then, when the remaining power for transmitting a signal at the set transmission power is insufficient in the PT-RS port, base station 400 instructs mobile station 300 to apply the transmission power adjustment described in embodiment 1. That is, when there is an instruction to adjust the transmission power from base station 400, mobile station 300 adjusts the transmission power so that it is equal to or less than the maximum transmission power for each antenna port, as described in embodiment 1.

[0125] Hereinafter, first and second specific operational examples of the mobile station 300 and the base station 400 will be described.

[0126] <Example 1> In the first operation example, the mobile station 300 first calculates the transmission power of the data signal using parameters and the like notified by the base station 400. In addition, the mobile station 300 calculates the transmission power of the data signal using the ratio ρ PTRS,i In other words, the mobile station 300 performs power boosting on the PT-RS.

[0127] Next, the mobile station 300 calculates PH, which is, for example, a value obtained by subtracting the calculated transmission power of data signals at all antenna ports from the maximum transmission power of the entire mobile station 300. Then, the mobile station 300 reports the calculated PH to the base station 400 as a PHR.

[0128] When the received PHR value is less than the threshold, the base station 400 determines that the mobile station 300 does not have sufficient spare power at the PT-RS port, and instructs the mobile station 300 to adjust (reduce) the transmission power as described in embodiment 1. This instruction may be notified explicitly or implicitly by an RRC signal or DCI.

[0129] When an instruction to adjust the transmission power is received, the mobile station 300 reduces the transmission power of the PT-RS or the data signal, as described in the first embodiment, and transmits the adjusted PT-RS, data signal, etc. to the base station 400.

[0130] In this manner, in the operation example 1, when the PHR calculated using the maximum transmission power of the entire mobile station 300 and the transmission power of a data signal is less than the threshold, the base station 400 instructs the mobile station 300 to adjust the transmission power. This allows the same PHR as in LTE to be used in the transmission power control, so that the mobile station 300 and the base station 400 can reduce the amount of additional configuration to be implemented for the transmission power control.

[0131] Here, the case where the PHR represents the remaining power in all antenna ports of the mobile station 300 has been described, but the present invention is not limited to this. For example, the PHR may be a value obtained by subtracting the transmission power of the data signal in the PT-RS port from the maximum transmission power in the PT-RS port. That is, when the PHR calculated using the maximum transmission power in the PT-RS port of the mobile station 300 and the transmission power of the data signal is less than a threshold, the base station 400 instructs the transmitter of the mobile station 300 to adjust the transmission power. This allows the base station 400 to grasp the transmission power status of the PT-RS port in more detail, and therefore to more accurately determine whether or not it is necessary to reduce the transmission power, and to instruct the mobile station 300 appropriately.

[0132] <Example 2> In the second operation example, the mobile station 300 first calculates the transmission power of data using parameters and the like notified by the base station 400, as in the first operation example. In addition, the mobile station 300 calculates the transmission power of data using the ratio ρ PTRS,i In other words, the mobile station 300 performs power boosting on the PT-RS.

[0133] Meanwhile, base station 400 instructs mobile station 300 on at least one of the waveform (eg, CP-OFDM or DFT-S-OFDM), MCS, and band (eg, the number of PRBs) to be used for transmitting a data signal.

[0134] Mobile station 300 determines whether or not to adjust transmission power as described in the first embodiment, based on at least one of the waveform, MCS, and band instructed by base station 400.

[0135] For example, when the notified waveform is "DFT-S-OFDM", as described in the first embodiment, the mobile station 300 reduces the transmission power of the PT-RS or data signal, and transmits the adjusted PT-RS, data signal, etc. to the base station 400. This is because when the notified waveform is DFT-S-OFDM (i.e., a single-carrier waveform), the mobile station 300 is likely to be located at a cell edge, and therefore the transmission power is likely to be extremely large.

[0136] Furthermore, when the notified MCS is "MCS lower than the threshold," as described in the first embodiment, the mobile station 300 reduces the transmission power of the PT-RS and data signal, and transmits the adjusted PT-RS, data signal, etc. to the base station 400. This is because, when the notified MCS is lower than the MCS within the range of advanced MCS at which the PT-RS is transmitted, the mobile station 300 is likely to be forced to transmit to the base station 400 in a noisy environment, and the transmission power is likely to be high.

[0137] Furthermore, when the notified band is "wider than a threshold", as described in the first embodiment, the mobile station 300 reduces the transmission power of the PT-RS and data signal, and transmits the adjusted PT-RS, data signal, etc. to the base station 400. This is because the transmission power of data increases depending on the allocated band, and therefore, when the notified band is wider than a certain value, there is a high possibility that the transmission power will be high.

[0138] In this way, the mobile station 300 may determine whether or not to adjust the transmission power based on one or more parameters of the waveform, MCS, and band used for data transmission.

[0139] That is, the base station 400 implicitly instructs the mobile station 300 on whether or not to apply the transmission power control as described in the first embodiment by notifying at least one of the waveform, the MCS, and the band. In this manner, with the implicit notification, it is not necessary to use the PHR described in the operation example 1 in the transmission power control. Therefore, the mobile station 300 and the base station 400 can reduce the amount of configuration to be additionally implemented for the transmission power control.

[0140] Operational examples 1 and 2 have been described above.

[0141] Thus, in this embodiment, when performing non-coherent transmission or partially coherent transmission, the mobile station 300 transmits a data signal at a specified transmission power and transmits the PT-RS with power boosting. At this time, if the base station 400 determines that the PT-RS port of the mobile station 300 does not have enough remaining power for transmission at the set transmission power, it instructs the mobile station 300 to adjust the transmission power so that it falls within the maximum transmission power for each antenna port. The mobile station 300 performs transmission power control according to the instruction from the base station 400.

[0142] As a result, similarly to embodiment 1, even in transmission in which power cannot be adjusted between antenna ports, such as non-coherent transmission or partially coherent transmission, mobile station 300 can transmit PT-RS at as high a power as possible within a range not exceeding the maximum transmission power for each antenna port, according to the remaining transmission power of mobile station 300. As a result, base station 400 is expected to improve the transmission speed / transmission efficiency by improving the accuracy of noise estimation.

[0143] In addition, by adjusting the transmission power so that it falls within the maximum transmission power for each antenna port, the mobile station 300 can prevent signals from being transmitted at lower power than intended or from being distorted when the mobile station 300 has little spare transmission power.

[0144] Furthermore, in this embodiment, base station 400 instructs mobile station 300 to adjust transmission power, so that mobile station 300 and base station 400 can communicate with each other with the same understanding of transmission power.

[0145] (Embodiment 3) In this embodiment, a case will be described in which a transmitter (i.e., a mobile station) transmits a PT-RS with power boosting in the uplink. Also, in this embodiment, the mobile station determines whether or not it is necessary to adjust the transmission power as described in the first embodiment.

[0146] [Communication system overview] The communication system according to this embodiment includes a mobile station 500 (transmitter) and a base station 600 (receiver). The PT-RS is transmitted from the mobile station 500 to the base station 600.

[0147] [Mobile station configuration] Fig. 16 is a block diagram showing the configuration of a mobile station 500 (transmitter) according to this embodiment. In Fig. 16, the same components as those in embodiment 1 (Fig. 6) are given the same reference numerals, and the description thereof will be omitted. Specifically, the operations of control unit 501 and error correction coding unit 502 are partially different from those of control unit 101 and error correction coding unit 102 shown in Fig. 6.

[0148] The control unit 501 calculates PH, which indicates the transmission power margin of the mobile station 500, generates a PHR to be reported to the base station 600, and outputs it to the error correction coding unit 502. Furthermore, the control unit 501 determines whether or not to apply the transmission power control (transmission power adjustment) described in the first embodiment based on the calculated PH value. Then, the control unit 501 determines the transmission power of the transmission signals such as the data signal and the PT-RS according to the determination result. The control unit 501 outputs the determined transmission power information to the signal allocation unit 104.

[0149] Error correction coding section 502 performs error correction coding on the input transmission data signal or the PHR input from control section 501 , and outputs the signal after error correction coding to modulation section 103 .

[0150] [Base station configuration] Fig. 17 is a block diagram showing the configuration of base station 600 (receiver) according to this embodiment. In Fig. 17, the same components as those in embodiment 1 (Fig. 7) are given the same reference numerals, and their description will be omitted. Specifically, base station 600 shown in Fig. 17 newly includes control unit 602 in addition to the configuration of receiver 200 shown in Fig. 7. Also, the operations of channel estimation unit 603 and error correction decoding unit 601 differ from the operations of channel estimation unit 204 and error correction decoding unit 207 shown in Fig. 7.

[0151] The error correction decoding unit 601 decodes the demodulated signal input from the data demodulation unit 206, and outputs the obtained received data signal. The error correction decoding unit 601 also extracts the PHR from the data signal, and outputs the PHR to the control unit 602.

[0152] The control unit 602 judges whether or not the mobile station 500 applies the transmission power control described in the first embodiment based on the PHR input from the error correction decoding unit 601. The control unit 602 outputs, based on the judgment result, to the channel estimation unit 603, "information on the amplitude of the PT-RS, etc." indicating whether or not the transmission power control described in the first embodiment is applied to the signal received from the mobile station 500.

[0153] The channel estimation unit 603 estimates a channel using the DMRS input from the signal separation unit 203. At this time, the channel estimation unit 603 may estimate a channel using the PT-RS. When the PT-RS is used, the channel estimation unit 603 may determine an amplitude (power) ratio between the PT-RS and the data signal based on amplitude information of the PT-RS, etc. input from the control unit 602. The channel estimation unit 603 outputs a channel estimation value (channel information) to the data demodulation unit 206.

[0154] In addition, if PT-RS is not used in channel estimation by channel estimation section 603, the above-mentioned configuration of base station 600 is not necessary, and the base station may have a configuration similar to that of receiver 200 shown in FIG.

[0155] [Operation of mobile station 500 and base station 600] Next, the operation of the mobile station 500 and the base station 600 will be described in detail.

[0156] In the uplink, the mobile station 500 performs non-coherent transmission or partially coherent transmission using a high frequency band and a high-order modulation level.

[0157] The mobile station 500 also determines whether or not "the remaining power for transmission at the set transmission power in the PT-RS port is insufficient", that is, whether or not a transmission power adjustment is necessary.

[0158] Then, when the remaining power for transmitting a signal at the set transmission power is insufficient at the PT-RS port, mobile station 500 performs the transmission power adjustment described in the first embodiment.

[0159] On the other hand, the base station 600, like the mobile station 500, judges whether or not the mobile station 500 has "insufficient remaining power for transmission at the set transmission power at the PT-RS port." If the mobile station 500 has insufficient remaining power for transmitting a signal at the set transmission power at the PT-RS port, the base station 600 judges that the mobile station 500 will transmit a signal by applying the transmission power control described in the first embodiment. In this case, the base station 600 performs channel estimation, for example, taking into consideration that the transmission power of the PT-RS or data signal has been reduced.

[0160] A specific example of the operation of the mobile station 500 and the base station 600 will now be described.

[0161] In this operation example, the mobile station 500 first calculates the transmission power of the data signal using parameters and the like notified by the base station 600. In addition, the mobile station 500 calculates the transmission power of the data signal using the ratio ρ PTRS,i In other words, the mobile station 500 performs power boosting on the PT-RS.

[0162] Next, the mobile station 500 calculates PH, which is, for example, a value obtained by subtracting the calculated transmission power of data signals at all antenna ports from the maximum transmission power of the entire mobile station 500. Then, the mobile station 500 reports the calculated PH to the base station 600 as a PHR.

[0163] Furthermore, if the calculated PH value is less than a threshold value, the mobile station 500 determines that there is insufficient spare power in the PT-RS port of the mobile station 500, and as described in embodiment 1, reduces the transmission power of the PT-RS or data signal, and transmits the adjusted PT-RS and data signal, etc. to the base station 600.

[0164] Similarly, when the PHR value reported from the mobile station 500 is less than a threshold value, the base station 600 determines that the transmission power adjustment as described in embodiment 1 has been applied to the received data signal or PT-RS, and performs channel estimation taking into account the reduction in transmission power.

[0165] In this manner, in the operation example, when the PHR calculated using the maximum transmission power of the entire mobile station 500 and the transmission power of a data signal is less than the threshold, the mobile station 500 adjusts the transmission power, and the base station 600 determines that the transmission power adjustment is to be performed in the mobile station 500. This allows the same PHR as in LTE to be used in the transmission power control, so that the mobile station 500 and the base station 600 can reduce the amount of configuration to be additionally implemented for the transmission power control.

[0166] Here, the case where the PHR represents the remaining power in all antenna ports of the mobile station 500 has been described, but the present invention is not limited to this. For example, the PHR may be a value obtained by subtracting the transmission power of the data signal in the PT-RS port from the maximum transmission power in the PT-RS port. That is, when the PHR calculated using the maximum transmission power in the PT-RS port of the mobile station 500 and the transmission power of the data signal is less than a threshold, the mobile station 500 adjusts the transmission power. This allows the mobile station 500 and the base station 600 to grasp the transmission power status of the PT-RS port in more detail, and therefore to more accurately determine whether or not it is necessary to reduce the transmission power.

[0167] An operation example has been described above.

[0168] Thus, in this embodiment, when performing non-coherent transmission or partially coherent transmission, the mobile station 500 transmits a data signal at a specified transmission power and transmits the PT-RS with power boosting. At this time, when the mobile station 500 determines that there is insufficient remaining power for transmission at the set transmission power in the PT-RS port of the mobile station 500, it adjusts the transmission power so that it falls within the maximum transmission power for each antenna port.

[0169] As a result, similarly to the first embodiment, even in transmission in which power cannot be adjusted between antenna ports, such as non-coherent transmission or partially coherent transmission, mobile station 500 can transmit PT-RS at as high a power as possible within a range not exceeding the maximum transmission power for each antenna port, according to the remaining transmission power of mobile station 500. As a result, base station 600 can expect to improve the transmission speed / transmission efficiency by improving the accuracy of noise estimation.

[0170] In addition, by adjusting the transmission power so that it falls within the maximum transmission power for each antenna port, the mobile station 500 can prevent signals from being transmitted at a lower power than intended or from being distorted when the mobile station 500 has little spare transmission power.

[0171] Furthermore, in this embodiment, since mobile station 500 determines whether or not to adjust the transmission power, appropriate transmission power can be set without waiting for an instruction from base station 600.

[0172] The embodiments of the present disclosure have been described above.

[0173] (Other embodiments) (1) "CPE / ICI correction" used in the above embodiment means "correcting CPE", "correcting ICI", or "correcting both CPE and ICI".

[0174] (2) In the above embodiment, uplink transmission is mainly assumed, but the above-described transmission power control may also be applied to downlink transmission.

[0175] (3) In the above embodiment, non-coherent transmission and partially coherent transmission are assumed, but the contents of the present disclosure can also be applied to transmission methods other than these.

[0176] (4) In the above embodiment, a case where data is transmitted using two antenna ports (1000, 1001) has been described as an example. However, the number of antenna ports for transmitting data is not limited to two, and a number of antenna ports other than two may be used. However, when there is only one antenna port capable of transmitting data, it is not possible to "use the power of resources not used by other antenna ports," and therefore it is assumed that power boosting of the PT-RS will not be applied.

[0177] Also, although the case where the PT-RS is mapped to one antenna port has been described, the number of antenna ports to which the PT-RS is mapped is not limited to one, and the number of antenna ports to which the PT-RS is mapped may be two or more.

[0178] (5) The PHR used in the second and third embodiments may be transmitted periodically, or may be transmitted whenever there is a change in the transmission power margin. Also, whenever there is a change in the transmission power margin, the application and cancellation of the reduction in transmission power described in the first embodiment may be switched.

[0179] (6) When a control channel (PDCCH (Physical Downlink Control CHannel), PUCCH (Physical Uplink Control CHannel)) and a data channel (PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel)) are frequency-multiplexed, the PT-RS may be mapped to that symbol.

[0180] (7) In the above embodiment (FIG. 1), the slot length is assumed to be 14 symbols, but the slot length is not limited to 14 symbols and may be, for example, 7 symbols or another number of symbols.

[0181] (8) The present disclosure can be realized by software, hardware, or software linked to hardware. Each functional block used in the description of the above embodiment may be realized, in part or in whole, as an LSI, which is an integrated circuit, and each process described in the above embodiment may be controlled, in part or in whole, by one LSI or a combination of LSIs. The LSI may be composed of individual chips, or may be composed of one chip so as to include some or all of the functional blocks. The LSI may have input and output data. Depending on the degree of integration, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI. The method of integration is not limited to LSI, and may be realized by a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, a field programmable gate array (FPGA) that can be programmed after LSI manufacture, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI may be used. The present disclosure may be realized as digital processing or analog processing. Furthermore, if an integrated circuit technology that can replace LSI appears due to the progress of semiconductor technology or a different derived technology, it is natural that such technology may be used to integrate the functional blocks. The application of biotechnology, etc. is also a possibility.

[0182] The transmitter of the present disclosure comprises a control circuit that determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding the maximum transmission power for each antenna port, and a transmission circuit that transmits the PT-RS and the data signal at the determined transmission power.

[0183] In the transmitter of the present disclosure, when the transmission power set at a first antenna port from which the PT-RS is transmitted exceeds the maximum transmission power of the first antenna port, the control circuit adjusts the transmission power to be equal to or less than the maximum transmission power for each antenna port.

[0184] In the transmitter of the present disclosure, the control circuit reduces the transmission power of the PT-RS and the data signal transmitted from all antenna ports while maintaining the power ratio between the PT-RS and the data signal.

[0185] In the transmitter of the present disclosure, the control circuit reduces the transmission power at the first antenna port and does not reduce the transmission power at antenna ports other than the first antenna port.

[0186] In the transmitter of the present disclosure, the control circuit reduces the transmission power of the PT-RS and the data signal transmitted from the first antenna port while maintaining the power ratio between the PT-RS and the data signal.

[0187] In the transmitter of the present disclosure, the control circuit reduces the transmission power of the data signal at the first antenna port and does not reduce the transmission power of the PT-RS.

[0188] In the transmitter of the present disclosure, the control circuit reduces the transmission power of some resource elements to which the data signal is mapped at the first antenna port, and does not reduce the transmission power of the data signal and the PT-RS mapped to resource elements other than the some resource elements.

[0189] In the transmitter of the present disclosure, the control circuit reduces the transmission power of the PT-RS at the first antenna port and does not reduce the transmission power of the data signal.

[0190] In the transmitter of the present disclosure, the transmitter is a mobile station, and the control circuit adjusts the transmission power so that it is equal to or less than a maximum transmission power for each antenna port when instructed by a base station.

[0191] In the transmitter of the present disclosure, when a PHR (Power Headroom Report) calculated using the maximum transmission power of the entire transmitter and the transmission power of the data signal is less than a threshold, the base station instructs the transmitter to adjust the transmission power.

[0192] In the transmitter of the present disclosure, when a PHR (Power Headroom Report) calculated using the maximum transmission power at the antenna port from which the PT-RS of the transmitter is transmitted and the transmission power of the data signal is less than a threshold, the base station instructs the transmitter to adjust the transmission power.

[0193] In the transmitter of the present disclosure, the control circuit determines whether or not to adjust the transmission power based on at least one of a signal waveform, a coding and modulation scheme, and an assigned band, which are instructed by the base station.

[0194] In the transmitter of the present disclosure, the transmitter is a mobile station, and the control circuit adjusts the transmission power so that it is equal to or less than a maximum transmission power for each antenna port.

[0195] In the transmitter of the present disclosure, the control circuit adjusts the transmission power when a Power Headroom Report (PHR) calculated using the maximum transmission power of the entire transmitter and the transmission power of the data signal is less than a threshold value.

[0196] In the transmitter of the present disclosure, the control circuit adjusts the transmission power when a PHR (Power Headroom Report) calculated using the maximum transmission power at the antenna port from which the PT-RS of the transmitter is transmitted and the transmission power of the data signal is less than a threshold value.

[0197] The transmission method disclosed herein determines the transmission power of a phase tracking reference signal (PT-RS) and a data signal within a range not exceeding the maximum transmission power for each antenna port, and transmits the PT-RS and the data signal at the determined transmission power. [Industrial Applicability]

[0198] One aspect of the present disclosure is useful for mobile communication systems. [Explanation of symbols]

[0199] 100,300,500 Transmitters 101,306,402,501,602 Control section 102,307,403,502 Error correction coding section 103,404 Modulation section 104,405 Signal Allocation Section 105,406 Transmitter 106,201,301,407 Antenna 200,400,600 Receiver 202,302 Receiver 203,303 Signal separation section 204,408,603 Channel Estimation Unit 205 CPE / ICI Estimation Department 206,304 Data demodulation section 207,305,401,601 Error correction decoding section

Claims

1. A transmitter that transmits an instruction to a terminal to determine whether to adjust the transmission power of a phase tracking reference signal (PT-RS) after power boosting is applied by changing a power ratio between the PT-RS and a data signal in non-coherent transmission or partially coherent transmission; a receiving unit that receives the PT-RS transmitted from the terminal with a transmission power adjusted based on the instruction; Equipped with Base station.

2. The transmission power of the PT-RS is adjusted to be equal to or less than the maximum transmission power of the antenna port through which the PT-RS is transmitted. The base station according to claim 1 .

3. Based on the instruction, the transmission power of the antenna port through which the PT-RS is transmitted is adjusted, and the transmission power of antenna ports other than the antenna port is not adjusted. The base station according to claim 1 .

4. Based on the instruction, the transmission power of the PT-RS is adjusted, and the transmission power of the data signal is not adjusted. The base station according to claim 1 .

5. Based on the instruction, the transmission power per resource element (RE) of the PT-RS is adjusted to be greater than the transmission power per RE of a data signal. The base station according to claim 1 .

6. determining whether the transmission power per resource element (RE) of the PT-RS is adjusted to be greater than a transmission power per RE of a data signal based on the indication; The base station according to claim 1 .

7. When a PHR (Power Headroom Report) calculated using the maximum transmission power of the entire terminal and the transmission power of a data signal is less than a threshold, the transmission power is adjusted. The base station according to claim 1 .

8. When a PHR (Power Headroom Report) calculated using the maximum transmission power of the antenna port from which the PT-RS of the terminal is transmitted and the transmission power of a data signal is less than a threshold, the transmission power is adjusted. The base station according to claim 1 .

9. The transmitter transmits at least one instruction of a signal waveform, a coding and modulation scheme, and an assigned band; determining whether the transmission power per resource element (RE) of the PT-RS is adjusted to be greater than a transmission power per RE of a data signal based on the indication; The base station according to claim 1 .

10. A base station transmits an instruction to a terminal to determine whether to adjust the transmission power of a phase tracking reference signal (PT-RS) after applying power boosting by changing a power ratio between the PT-RS and a data signal in non-coherent transmission or partially coherent transmission; The base station receives the PT-RS transmitted from the terminal with a transmission power adjusted based on the instruction. Receiving method.

11. A process of transmitting an instruction to a terminal to determine whether to adjust the transmission power of a phase tracking reference signal (PT-RS) after applying power boosting by changing a power ratio between the PT-RS and a data signal in non-coherent transmission or partially coherent transmission; receiving the PT-RS transmitted from the terminal with a transmission power adjusted based on the instruction; Controlling Integrated circuits.

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