Peak suppression device and peak suppression method

Abstract

To provide a peak suppression device that makes a tap coefficient of a bandlimiting filter determined by executing processing for making the tap coefficient and an input signal similar to each other at every predetermined period of time.SOLUTION: A peak suppression device comprises a peak suppression circuit which changes a tap coefficient of a bandlimiting filter for use in a peak pulse according to an input signal and which outputs an output signal suppressing a peak. The peak suppression device makes the tap coefficient determined by executing processing for making the tap coefficient and the input signal similar to each other at every predetermined period of time. The processing for making them similar to each other is processing for increasing the tap coefficient of time exceeding a predetermined threshold and decreasing the tap coefficient of time not exceeding the predetermined threshold.SELECTED DRAWING: Figure 22

Description

[Technical Field]

[0001] The present disclosure relates to a peak suppression device and a peak suppression method. [Background technology]

[0002] In recent years, in the field of mobile communications, techniques such as OFDM (Orthogonal Frequency Division Multiplex) modulation have been adopted for signals to improve transmission efficiency. Furthermore, RUs (Radio Units) and AASs (Active Antenna Systems) are increasingly using CCs (Component Carriers) from multiple vendors in a wideband environment for sharing. OFDM modulation techniques use multilevel QAM (Quadrature Amplitude Modulation). Multilevel QAM techniques such as 256QAM and 1024QAM have been adopted in recent years to transmit a large amount of data with a single modulation, and these standards also require stricter EVM (Error Vector Magnitude).

[0003] To reduce the size of the device, low power consumption is required, and the power amplifier must be operated in a low-output back-off state, where the output level approaches the saturation power of the power amplifier. To achieve this, it is necessary to reduce the PAPR (Peak to Average Power Ratio) of the signal input to the power amplifier.

[0004] Generally, peak suppression methods are classified into clipping and filtering and peak cancellation. Clipping and filtering has the drawback of causing a large spread of spectrum near CC, and has been used less in recent years. Peak cancellation tends to suppress the spread of spectrum near CC more effectively than clipping and filtering. However, in recent years, there has been a demand for wideband signal transmission, and the filters used in peak cancellation to band-limit peak pulses degrade EVM, making it difficult to meet standards.

[0005] Patent Document 1 discloses a transmitter that suppresses the peak level of a multi-carrier signal in which a plurality of carrier signals are combined, and maintains high signal quality for all transmission signal patterns. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-199490 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the peak power suppression means described in Patent Document 1 uniformly suppresses signals using a band-limiting filter. Therefore, an object of the present disclosure is to provide a peak suppression device in which the tap coefficients of the band-limiting filter are determined by performing a process to make the tap coefficients and the input signal similar at predetermined time intervals. [Means for solving the problem]

[0008] The peak suppression device of the present disclosure comprises: a peak suppression circuit that changes a tap coefficient of a band limiting filter used for a peak pulse in accordance with an input signal and outputs an output signal in which the peak is suppressed; The tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals.

[0009] The peak suppression method of the present disclosure includes: A peak suppression method for outputting an output signal in which peaks are suppressed by changing tap coefficients of a band-limiting filter used for a peak pulse in accordance with an input signal, The tap coefficients are determined by a peak suppression method in which a process is performed every predetermined time to make the tap coefficients and the input signal similar to each other. [Effects of the Invention]

[0010] The present disclosure provides a peak suppression device in which the tap coefficients of a band-limiting filter are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 10 is a block diagram showing the configuration of a related peak suppression circuit. [Figure 2] FIG. 10 is a diagram illustrating an example of tap coefficients of a band-limiting filter in a related peak suppression circuit. [Figure 3] FIG. 10 is a diagram illustrating an example of tap coefficients of a band-limiting filter in a related peak suppression circuit. [Figure 4] FIG. 10 is a diagram illustrating an example of the frequency characteristics of a band-limiting filter in a related peak suppression circuit. [Figure 5] 10A and 10B are diagrams illustrating an example of a comparison of power before and after peak suppression processing by a related peak suppression circuit. [Figure 6] 1 is a flowchart of a method for generating a band-limiting filter according to the present disclosure. [Figure 7] FIG. 2 is a diagram illustrating definitions regarding frequency characteristics of a band-limiting filter according to the present disclosure. [Figure 8] 10A and 10B are diagrams illustrating a comparison of power and IQ signals before and after peak suppression processing according to the present disclosure. [Figure 9] 10A and 10B are diagrams illustrating adjustment of a band-limiting filter according to the present disclosure and changes in frequency characteristics. [Figure 10] 10A and 10B are diagrams illustrating a comparison of power and IQ signals before and after peak suppression processing according to the present disclosure. [Figure 11] 1 is a block diagram showing a configuration of a peak suppression circuit according to the present disclosure. [Figure 12] FIG. 1 is a diagram illustrating a configuration of an embodiment of wireless communication according to the present disclosure. [Figure 13] 10A and 10B are diagrams illustrating a comparison of power changes due to peak suppression processing between a related system and the system of the present disclosure. [Figure 14] FIG. 10 is a diagram showing a comparison of errors with respect to the power of the input signal between the related method and the method of the present disclosure. [Figure 15] FIG. 10 is a diagram showing a comparison of errors with respect to an input signal I between the related method and the method of the present disclosure. [Figure 16] FIG. 10 is a diagram showing a comparison of errors with respect to an input signal Q between the related method and the method of the present disclosure. [Figure 17] FIG. 10 is a block diagram showing the configuration of another peak suppression circuit according to the present disclosure. [Figure 18] 10A and 10B are diagrams illustrating an example of power or amplitude of peak suppression processing according to the present disclosure. [Figure 19] FIG. 10 illustrates an example of the power or amplitude of a peak pulse according to the present disclosure. [Figure 20] 10A and 10B are diagrams illustrating an example of power or amplitude of peak suppression processing according to the present disclosure. [Figure 21] FIG. 10 illustrates an example of the power or amplitude of a peak pulse according to the present disclosure. [Figure 22] 1 is a block diagram showing a configuration of a peak suppression device according to the present disclosure. [Figure 23] FIG. 1 is a block diagram illustrating a configuration of an information processing device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Description of related peak suppression circuits) FIG. 1 is a block diagram showing the configuration of a related peak suppression circuit. In the drawing, unidirectional arrows indicating the flow of signals and the connection relationships of each element simply indicate the direction of the flow of a certain signal or data, and do not exclude bidirectionality. An example configuration of a peak suppression circuit 10 will be explained below using FIG. 1. An input signal to the peak suppression circuit 10 is input to a delay unit 15, a power conversion unit 11, and a peak detection unit 12. The signal input to the delay unit 15 is delayed by the processing times of the power conversion unit 11, the peak detection unit 12, the peak pulse generation unit 13, and the band-limiting filter 14.

[0013] The power conversion unit 11 has a function of converting an input signal into power. The power of the input signal is expressed as I where I is the in-phase and Q is the quadrature-phase. 2 +Q 2 The calculated power is input to the peak detection unit 12. The peak detection unit 12 determines whether the power of the input signal is equal to or greater than a threshold. If it is equal to or greater than the threshold, the peak detection unit 12 inputs the magnitude exceeding the threshold to the peak pulse generation unit 13.

[0014] The peak pulse generator 13 generates a peak suppression pulse in which an input signal exceeding a threshold is suppressed to a threshold based on the value input from the peak detector 12. For example, the power threshold of the input signal is set as I where I is the in-phase and Q is the quadrature-phase, respectively. 2 +Q 2 When the input signal 2.0+j0.0 is input to the peak detector 12, its power is set as I 2 +Q 2 = 4, which exceeds the threshold. 2 +Q 2 To reduce it to =1, simply subtract 1.0+j0.0 from the input signal.

[0015] Therefore, peak pulse generator 13 generates 1.0+j0.0. The generated peak pulse is input to band-limiting filter 14. Band-limiting filter 14 is a filter for limiting the band of the peak pulse. Because the frequency components of the pulse have equal values ​​for all frequencies, the frequency components of the output signal added to the output of delay unit 15 appear in signals other than the input signal. Frequency components different from the input signal are unnecessary for wireless devices and must be reduced to below a certain level. Such unnecessary waves are called unwanted waves. For this reason, the band-limiting filter used for the peak pulse is designed taking into account the frequency characteristics and sampling rate of the transmission data.

[0016] FIG. 2 is a diagram showing an example of tap coefficients of a band-limiting filter in a related peak suppression circuit. FIG. 3 is a diagram showing an example of tap coefficients of a band-limiting filter in a related peak suppression circuit. FIG. 4 is a diagram showing an example of frequency characteristics of a band-limiting filter in a related peak suppression circuit. Specific band-limiting filter tap coefficients are shown in FIGS. 2 and 3. Furthermore, the frequency characteristics of the band-limiting filter are shown in FIG. 4. Here, it is assumed that the CC (Component Carrier) of the input signal has a 50 MHz band for -165 MHz, a 40 MHz band for -80 MHz, and an 80 MHz band for +165 MHz. In FIG. 3, the time when the relative time on the horizontal axis is 0 is defined as the peak detection time, and the tap coefficient at the peak detection time is set to 1. Since tap coefficients other than those at the peak detection time do not require peak suppression processing, there is a risk of degrading the EVM.

[0017] Figure 5 shows an example of a comparison of power before and after peak suppression processing by a related peak suppression circuit. A specific example of applying the band-limiting filter of Figure 3 to an input signal is shown in Figure 5. The vertical axis represents the signal power I 2 +Q 25 shows the power of the output signal at time 0 after peak suppression processing, with the power of the output signal at time 0 being 1, and the peak being suppressed up to the threshold. However, the power of the output signal at times other than time 0 also changes before and after peak suppression processing. As such, a problem with wideband band-limiting filters is that the power changes even at times other than when peak suppression is desired.

[0018] (Description of Peak Suppression Device According to First Embodiment) 12 is a diagram showing a configuration of an embodiment of wireless communication according to the present disclosure. A wireless communication device transmitter 120 in which a peak suppression device according to the present disclosure is used will be described with reference to FIG.

[0019] The peak suppression circuit included in the peak suppression device according to the present disclosure is used in the peak suppression circuit 123 shown in FIG. 12. The baseband 121 constructs data to be transmitted using a modulation method such as OFDM (Orthogonal Frequency Division Multiplex) based on data received from a DU (Distributed Unit) or the like. The DUC 122 is composed of an NCO and an up-sampling process to construct a CC, which is a single continuous frequency band. The DUC is a Digital Up Converter. The CC is a Component Carrier. The NCO is a Numerically Controlled Oscillator.

[0020] The peak suppression circuit 123 has a function of suppressing the peak components of the input signal received from the DUC to a predetermined value or less. There is an upper limit to the power that can be output by the PA (Power Amplifier) ​​connected in the subsequent stage, and the power of the input signal needs to be reduced to below the upper limit, so peak suppression is performed.

[0021] Furthermore, the higher the average power of the input signal, the more efficient the PA becomes. Therefore, by lowering the PAPR (Peak to Average Power Ratio) of the input signal, it is possible to input a high average power into the PA while keeping the input signal below the upper limit of what the PA can output.

[0022] DPD (Digital Pre-Distortion) 124 removes distortion components from the signal output from the PA by inputting a signal that has been calculated to predict the distortion components of the PA to the PA. The signal output from the PA is input to ADC (Analog to Digital Converter) 126, where it is converted from an analog signal to a digital signal. This digital signal is the output signal of the PA, and therefore contains distortion components caused by the PA. DPD performs calculations to cancel out these distortion components and outputs the resulting signal.

[0023] A DAC (Digital to Analog Converter) 125 converts a digital signal into an analog signal. An LPF (Low Pass Filter) 127 removes high-frequency components different from the CC generated by the DAC. An LO (Local Oscillator) 128 can increase the frequency of the CC to a specific frequency by multiplying the output of the LPF by a specific frequency.

[0024] In this way, a CC is placed in a predetermined frequency band and a signal is output from wireless communication device transmitter 120. The present disclosure improves EVM by reducing signal degradation caused by peak suppression processing in a peak suppression circuit in a wireless communication device transmitter.

[0025] (Description of Peak Suppression Circuit According to First Embodiment) Fig. 11 is a block diagram showing the configuration of a peak suppression circuit according to the present disclosure. The peak suppression circuit according to the present disclosure will be described with reference to Fig. 11. The peak suppression circuit according to the present disclosure differs from the related peak suppression circuit in Fig. 1 in the method of calculating the tap coefficients of the band-limiting filter.

[0026] The method for designing the associated band-limiting filter takes into account the CC frequency band to prevent unwanted waves from being output in bands other than the CC. The method for designing the associated band-limiting filter then designs the tap coefficients so that the ripple fluctuation level in the passband is small, the frequency width of the transition band is narrow, and the attenuation level in the attenuation band is large. Therefore, the associated band-limiting filter is designed independently of the time fluctuation of the input signal. If the CC is wide and discontinuous, the time fluctuation of the tap coefficients is large even at times other than relative time 0 in Figure 3, degrading the EVM.

[0027] 11, an input signal to peak suppression circuit 100 is input to delay unit 106, power conversion unit 101, and peak detection unit 102. The input signal input to the delay unit is delayed by the processing time required for the input signal input to power conversion unit 101 and peak detection unit 102 to be output from band limiting filter 105.

[0028] The power conversion unit 101 converts the input signal into power. The power of the input signal is expressed as I where I is the in-phase and Q is the quadrature-phase. 2 +Q 2 The calculated power is input to peak detection unit 102. Peak detection unit 102 determines whether the power of the input signal is equal to or greater than a predetermined value, i.e., a threshold. If the power of the input signal is equal to or greater than the threshold, peak detection unit 102 inputs the input signal that exceeded the threshold and the time at which it did so to peak pulse generation unit 103. Furthermore, peak detection unit 102 inputs an input signal that is equal to the tap coefficient length of the band-limiting filter, centered on the time at which the input signal exceeded the threshold, to band-limiting filter generation unit 104.

[0029] For example, if the tap coefficient length is 2049 taps, the input signal is targeted from -1024 to +1024, with the detected peak at time 0. The peak pulse generation unit 103 generates a peak pulse by suppressing the input signal that exceeds the threshold value to the threshold value based on the value input from the peak detection unit 102.

[0030] The generated peak pulse is input to the band-limiting filter generation unit 104. The band-limiting filter generation unit 104 generates tap coefficients of the band-limiting filter using information on the peak pulse and the input signal. A method for generating the tap coefficients of the band-limiting filter will be described later.

[0031] Band-limiting filter 105 performs band-limiting processing on the peak pulse input from peak pulse generating unit 103 using tap coefficients input from band-limiting filter generating unit 104. The band-limited peak pulse output from band-limiting filter 105 is multiplied by -1 and combined with the input signal delayed by delay unit 106. By performing processing in peak suppression circuit 100, the peak of the input signal is suppressed to a threshold value.

[0032] (Description of a Method for Generating a Band-Limiting Filter According to the First Embodiment) 6 is a flowchart of a method for generating a band-limiting filter according to the present disclosure. The method for generating a band-limiting filter according to the present disclosure will be described with reference to FIG.

[0033] 6, a band-limiting filter according to the frequency characteristics of the input signal is generated in step 61. This band-limiting filter is generated by a method that takes into account the frequency characteristics, similar to the band-limiting filter shown in FIG.

[0034] Step 62 defines the passband ripple, transition band frequency width, and attenuation band attenuation level required for the band-limiting filter. Figure 7 is a diagram showing definitions related to the frequency characteristics of the band-limiting filter according to the present disclosure. These definitions are determined by the input signal, the threshold value of the peak detection unit 102, and the standard for the level of unwanted waves outside the frequency band of the input signal required for the output signal.

[0035] Step 63 defines the range of the tap coefficients that can be varied by adding, subtracting, multiplying or dividing in a single execution of step 65 .

[0036] Step 64 defines whether or not to adjust the tap coefficients for the relative time in Fig. 2. The tap coefficients to be adjusted at this time are selected by comparing the tap coefficients before and after the peak suppression processing in Fig. 5, for example, for the relative time between -7 and +7, which have the largest error.

[0037] In step 65, the EVM is improved and peak suppression processing is performed using the input signal and the tap coefficients of the band-limiting filter. FIG. 8 is a diagram showing a comparison of the power and IQ signal before and after the peak suppression processing according to the present disclosure. An overview of step 65 will be explained with reference to FIG. 8. FIG. 8 shows the comparison of the power IQ signal of the output signal when peak suppression processing is performed using the tap coefficients of the band-limiting filter before adjustment and before the processing is performed. 2 +Q 2 , signal I, and signal Q are shown.

[0038] Output signal power I 2 +Q 2 changes significantly between before and after processing from time -7 to +7. Ideally, it should be set to the threshold value of the peak detection unit only at time 0, and should be brought close to the value before peak suppression processing at other times. This is because doing so improves the EVM. Therefore, for the input signal, the tap coefficient at time 0 is increased and the other tap coefficients are relatively decreased. Note that step 65 is a step in which the input signal and the tap coefficients of the band limiting filter are used to improve the EVM and perform peak suppression processing, and the method for doing so is not limited to increasing the tap coefficient at time 0.

[0039] The contents of step 65 will be specifically explained using two examples. FIG. 18 is a diagram showing an example of power or amplitude in peak suppression processing according to the present disclosure. The time at which the peak is detected is set to 0, and time is locally shown from -2 to +2. FIG. 19 is a diagram showing an example of power or amplitude of a peak pulse according to the present disclosure. FIG. 19 shows the case of a band-limiting filter with tap coefficient 1 and tap coefficient 2. Here too, the time at which the peak is detected is set to 0, and time is locally shown from -2 to +2.

[0040] 18, after detecting a peak that is equal to or greater than the threshold at time 0, if peak suppression processing is performed using tap coefficient 1 shown in Fig. 19, the power or amplitude after peak suppression processing will be as shown in 1. In this case, in the EVM improvement and peak suppression processing performed in step 65 using the input signal and the tap coefficients of the band-limiting filter, peak suppression is desired only at time 0, and the tap coefficients are reduced at times other than time 0 to improve EVM.

[0041] Therefore, if the tap coefficients are 0.05, 0.1, 0.2, 0.1, and 0.05 in time 1 intervals from -2 to +2, and then set to +0.1 at time 0, all tap coefficients are multiplied by 2 / 3 to return the peak pulse at time 0 to 0.2. As a result, tap coefficient 2 used in the next processing in time 1 intervals from -2 to +2 is 0.033, 0.066, 0.2, 0.066, and 0.033. The result of peak suppression processing using tap coefficient 2 is shown in "After Peak Suppression Processing 2" in Figure 18. The peak at time 0 is below the threshold, and the EVM other than at time 0 has been improved.

[0042] FIG. 20 is a diagram illustrating an example of the power or amplitude of peak suppression processing according to the present disclosure. Next, step 65 will be described using FIG. 20. FIG. 20 illustrates a case where the signal before peak suppression processing is different from that in FIG. 18 and the time period during which the threshold is exceeded is other than 0. FIG. 21 is a diagram illustrating an example of the power or amplitude of a peak pulse according to the present disclosure. After detecting a peak that exceeds the threshold at time 0 shown in FIG. 20 and then performing peak suppression processing using tap coefficient 1 shown in FIG. 21, the power or amplitude becomes like "After Peak Suppression Processing 1." In this case, the difference between the values ​​before peak suppression processing and "After Peak Suppression Processing 1" at time -1 is large, resulting in poor EVM. Therefore, the EVM can be improved by reducing the value of tap coefficient 1 at time -1.

[0043] Also, at time +1, the difference between the values ​​before and after peak suppression processing is large but exceeds the threshold. Therefore, peak suppression is performed by increasing the value of tap coefficient 1 at time +1. Therefore, if the tap coefficients are 0.05, 0.1, 0.2, 0.1, and 0.05 in time 1 intervals from -2 to +2, for example, add -0.1 to the tap coefficient at time -1 and +0.1 to the tap coefficient at time +1. As a result, tap coefficient 2 used in the next step in time 1 intervals from -2 to +2 becomes 0.05, 0, 0.2, 0.2, and 0.05. The result of peak suppression processing using tap coefficient 2 is, as shown in After Peak Suppression Processing 2 in Figure 20, the peak at time 0 is below the threshold, the EVM at time -1 is improved, and the peak is suppressed at time +1.

[0044] In step 66, it is determined whether the ripple, transition band frequency width, and attenuation band attenuation level defined in step 62 are satisfied. FIG. 9 illustrates the adjustment of the band-limiting filter and the change in frequency characteristics according to the present disclosure. FIG. 9 shows the frequency characteristics of the band-limiting filter obtained by defining the tap coefficients at time 0 with the tap coefficient adjustment width set to 0.1 in step 63. For example, if definitions (1), (2), and (3) are not satisfied (NO in step 66), then 1.3 in FIG. 9 is adopted when the attenuation level of the attenuation band is set to -30 dB. That is, step 69 is executed to restore the tap coefficients of the band-limiting filter and exclude them from the tap coefficient adjustment sample. Then, step 65 multiplies the tap coefficients of the band-limiting filter at time 0 by 1.3. FIG. 10 illustrates a comparison of the power and IQ signals before and after peak suppression according to the present disclosure. In step 67, the EVM is considered to have improved if the difference between the values ​​before and after the peak suppression processing shown in FIG. 10 is less than a certain value. If the value is equal to or greater than the predetermined value (NO in step 67), step 65 is performed again. Step 68 determines whether all the tap coefficients defined in step 64 have been processed, and if all have been processed (YES in step 68), the peak suppression process ends. If not, they are excluded from the tap coefficient adjustment sample (NO in step 68) (step 70).

[0045] In this way, the tap coefficients are determined by performing a process of making the tap coefficients and the input signal similar at predetermined time intervals. The similarity process increases the tap coefficients for times when a predetermined threshold is exceeded and decreases the tap coefficients for times when the predetermined threshold is not exceeded. The present disclosure provides a peak suppression device including a peak suppression circuit.

[0046] Fig. 13 is a diagram comparing power changes due to peak suppression processing in the related method and the method of the present disclosure. Fig. 14 is a diagram comparing errors with respect to input signal power in the related method and the method of the present disclosure. Fig. 15 is a diagram comparing errors with respect to input signal I in the related method and the method of the present disclosure. Fig. 16 is a diagram comparing errors with respect to input signal Q in the related method and the method of the present disclosure. Results of peak suppression processing using the tap coefficients of the band-limiting filter of the method of the present disclosure are shown in Figs. 13, 14, 15, and 16.

[0047] FIG. 13 shows the time variation of normalized power of the input signal, the output signal of the related method, and the output signal of the method of the present disclosure. The signal at time 0 has its peak suppressed below the threshold, and the closer the signal is to the input signal other than time 0, the smaller the EVM. FIG. 14 shows the time variation of the error with respect to the power of the input signal of FIG. 13 calculated by the related method and the method of the present disclosure. The closer the error is to 0%, the closer the output signal is to the input signal. FIG. 15 shows the time variation of the error with respect to input signal I calculated by the related method and the method of the present disclosure. FIG. 16 shows the time variation of the error with respect to input signal Q calculated by the related method. As can be seen from each figure, the method of the present disclosure reduces error compared to the related method by taking into account the time variation of the input signal in the design of the area restriction filter. This has the effect of suppressing the peak of the output signal while bringing it closer to the input signal, improving the EVM.

[0048] (Explanation of Peak Suppression Circuit According to Second Embodiment) 17 is a block diagram showing the configuration of another peak suppression circuit according to the present disclosure. The peak suppression circuit according to the second embodiment is characterized in that it has N tap coefficients of a band-limiting filter in advance, and selects the tap coefficient with the best EVM by calculating the EVM for each tap coefficient.

[0049] Processing time can be reduced by selecting tap coefficients using band-limiting filter selection unit 174. Band-limiting filter selection unit 174 receives an input signal from peak detection unit 172, the length of which corresponds to the tap coefficients and is centered around a peak exceeding a threshold, and a peak pulse generated by peak pulse generation unit 173. The band-limiting filter selection unit has a plurality of N (N is a natural number) band-limiting filters 175 in advance. These band-limiting filters 175 satisfy predefined passband ripples, transition band frequency widths, and attenuation band attenuation levels, but each has a different tap coefficient. For example, these different tap coefficients are selected from frequently occurring tap coefficients generated from the tap coefficients generated in FIG. 6.

[0050] The peak pulse generated by peak pulse generator 173 is input to band limiting filter 175 where it is band limited. This signal is input to EVM calculator 176, which calculates the EVM by performing the following calculation with the output signal of peak detector 172:

number

[0051] The EVM calculation unit 176 inputs a signal obtained by performing band-limiting filter processing on the EVM and peak pulse to the band-limiting filter selection unit 177. The band-limiting filter selection unit 177 determines the smallest value from the N received EVMs, and outputs a signal obtained by performing band-limiting filter processing on the peak pulse. Alternatively, the band-limiting filter selection unit 177 selects a band-limiting filter that satisfies predetermined characteristics, such as the maximum value of the peak after peak suppression processing. The signal output from the band-limiting filter selection unit 174 is subtracted from the signal output from the delay unit 178, and the combined signals are output as a peak-suppressed signal. This fixes the calculation time for the tap coefficients, thereby shortening the processing time. As a result, the delay time in wireless communication can be kept below a certain level.

[0052] The peak pulse used in the peak suppression method is a wideband signal. A band-limiting filter is used to prevent unwanted waves from being output outside the band, but this causes degradation of the EVM. The peak suppression circuit disclosed herein improves the EVM by changing the tap coefficients of the band-limiting filter according to the input signal to the peak suppression circuit. Changing the tap coefficients according to the input signal changes the frequency characteristics of the band-limiting filter, but the passband ripple, transition band frequency width, and attenuation level of the attenuation band of the frequency characteristics are defined to determine whether they satisfy the standards. The frequency characteristics are defined so as not to output unwanted waves outside the band that violate wireless standards.

[0053] Fig. 22 is a block diagram showing the configuration of a peak suppression device according to the present disclosure. As shown in Fig. 22, peak suppression device 2200 includes peak suppression circuit 2201. Peak suppression circuit 2201 changes the tap coefficients of a band-limiting filter used for peak pulses in accordance with the input signal, and outputs an output signal with the peaks suppressed. Here, the tap coefficients are determined by performing a process of making the tap coefficients and the input signal similar at predetermined time intervals.

[0054] Fig. 23 is a block diagram showing the configuration of an information processing device of the present disclosure. A peak suppression device 2200 of the present disclosure is realized, for example, by an information processing device 2300. As shown in Fig. 23, the information processing device 2300 includes at least a processor 2301 that executes a program to perform processing, and a memory 2302 that stores the program.

[0055] The information processing device 2300 may be a single device or may be configured from multiple devices. The information processing device 2300 may be a cloud server that distributes and processes part or all of its functions.

[0056] Furthermore, part or all of the processing in the information processing device 2300 described above can be realized as a computer program. Such a program can be stored using various types of non-transitory computer-readable media and provided to a computer. Non-transitory computer-readable media include various types of tangible recording media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be provided to a computer by various types of temporary computer-readable media. Examples of temporary computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable media can provide the program to a computer via a wired communication path such as an electric wire or optical fiber, or via a wireless communication path.

[0057] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0058] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0059] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a peak suppression circuit that changes a tap coefficient of a band limiting filter used for a peak pulse in accordance with an input signal and outputs an output signal in which the peak is suppressed; A peak suppression device, wherein the tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals. (Appendix 2) The peak suppression device according to claim 1, wherein the process of making the signal similar is a process of increasing the tap coefficients when a predetermined threshold is exceeded and decreasing the tap coefficients when the predetermined threshold is not exceeded. (Appendix 3) The peak suppression circuit comprises: a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak detection unit that receives the input signal, the power converted by the power conversion unit, the length of the tap coefficients of the band-limiting filter, and the peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficients centered on the peak that exceeds the threshold; a peak pulse generating unit that receives a peak pulse time and the peak of the input signal that has exceeded the threshold value, and outputs the peak pulse; a band-limiting filter generating unit that receives the peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold value and generates the band-limiting filter; the band-limiting filter that passes the peak pulse and outputs a suppressed peak pulse, 2. The peak suppression device according to claim 1, wherein the output signal is generated by combining the delayed input signal with the suppressed peak pulse. (Appendix 4) The peak suppression circuit comprises: a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak pulse generating unit that receives the input signal, the power converted by the power converting unit, the length of the tap coefficients of the band-limiting filter, and a peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficients centered on the peak that exceeds the threshold; a band-limiting filter selection unit that receives the peak pulse and the input signal for a length of the tap coefficient centered on the peak that exceeds the threshold, and outputs a suppressed peak pulse, 2. The peak suppression device according to claim 1, wherein the output signal is generated by combining the delayed input signal with the suppressed peak pulse. (Appendix 5) the band-limiting filter selection unit includes a plurality of the band-limiting filters and an EVM calculation unit connected to each of the band-limiting filters; The peak suppression device according to claim 4, wherein the band-limiting filter selection unit selects the band-limiting filter by inputting the peak pulse to each of the band-limiting filters, and inputting the band-limited peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold to the EVM calculation unit. (Appendix 6) A peak suppression method for outputting an output signal in which peaks are suppressed by changing tap coefficients of a band-limiting filter used for a peak pulse in accordance with an input signal, A peak suppression method in which the tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals. (Appendix 7) The peak suppression method according to claim 6, wherein the process of making the signal similar is a process of increasing the tap coefficients when a predetermined threshold is exceeded and decreasing the tap coefficients when the predetermined threshold is not exceeded. (Appendix 8) a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak detection unit receives the input signal, the converted power, the length of the tap coefficient of the band-limiting filter, and the peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficient centered on the peak that exceeds the threshold; a peak pulse generating unit inputting a peak pulse time and the peak of the input signal exceeding the threshold value, and outputting the peak pulse; a band-limiting filter generating unit receives the peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold value, and generates the band-limiting filter; a band-limiting filter that passes the peak pulse and outputs a suppressed peak pulse; 7. The peak suppression method according to claim 6, wherein the delayed input signal and the peak pulse are combined to output the output signal. (Appendix 9) a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak pulse generating unit receives the input signal, the converted power, the length of the tap coefficient of the band-limiting filter, and a peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficient centered on the peak that exceeds the threshold; a band-limiting filter selection unit receives the peak pulse and the input signal for a length of the tap coefficient centered on the peak exceeding the threshold, and outputs a suppressed peak pulse; 7. The peak suppression method according to claim 6, wherein the delayed input signal and the suppressed peak pulse are combined to output the output signal. (Appendix 10) the band-limiting filter selection unit includes a plurality of the band-limiting filters and an EVM calculation unit connected to each of the band-limiting filters; 10. The peak suppression method according to claim 9, wherein the peak pulse is input to each of the band-limiting filters, and the band-limited peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold are input to the EVM calculation unit, so that the band-limiting filter selection unit selects the band-limiting filter. (Appendix 11) A program for causing a peak suppression device to change tap coefficients of a band limiting filter used for peak pulses in accordance with an input signal, and to output an output signal in which peaks are suppressed, The tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals.

[0060] Some or all of the elements (e.g., configurations and functions) described in Supplementary Note 2 to Supplementary Note 5 that are dependent on Supplementary Note 1 {e.g., device} may also be dependent on Supplementary Note 6 {e.g., method} and Supplementary Note 11 {e.g., program} in the same dependency relationship as Supplementary Note 2 to Supplementary Note 5. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0061] 10 Peak suppression circuit, 11 Power conversion unit, 12 Peak detection unit, 13 Peak pulse generation unit, 14 Band-limiting filter, 15 Delay unit, 100 Peak suppression circuit, 101 Power conversion unit, 102 Peak detection unit, 103 Peak pulse generation unit, 104 Band-limiting filter generation unit, 105 Band-limiting filter, 106 Delay unit, 120 Wireless communication device transmitter, 121 Baseband, 122 DUC, 123 Peak suppression circuit, 124 DPD, 125 DAC, 126 ADC, 127 LPF, 128 LO, 129 PA, 170 Peak suppression circuit, 171 Power conversion unit, 172 Peak detection unit, 173 Peak pulse generation unit, 174 Band-limiting filter selection unit, 175 Band-limiting filter, 175a Band-limiting filter 1, 175b Band-limiting filter 2, 176 EVM calculation unit, 176a EVM calculation unit, 176b EVM calculation unit, 177 band limiting filter, 178 delay unit

Claims

1. a peak suppression circuit that changes a tap coefficient of a band limiting filter used for a peak pulse in accordance with an input signal and outputs an output signal in which the peak is suppressed; A peak suppression device, wherein the tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals.

2. 2. The peak suppression device according to claim 1, wherein the process of making the tap coefficients similar to each other is a process of increasing the tap coefficients when a predetermined threshold is exceeded and decreasing the tap coefficients when the predetermined threshold is not exceeded.

3. The peak suppression circuit comprises: a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak detection unit that receives the input signal, the power converted by the power conversion unit, the length of the tap coefficients of the band-limiting filter, and the peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficients centered on the peak that exceeds the threshold; a peak pulse generating unit that receives a peak pulse time and the peak of the input signal that has exceeded the threshold value, and outputs the peak pulse; a band-limiting filter generating unit that receives the peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold value and generates the band-limiting filter; the band-limiting filter that passes the peak pulse and outputs a suppressed peak pulse, 2. The peak suppression device according to claim 1, wherein the output signal is generated by combining the delayed input signal and the suppressed peak pulse.

4. The peak suppression circuit comprises: a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak pulse generating unit that receives the input signal, the power converted by the power converting unit, the length of the tap coefficients of the band-limiting filter, and a peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficients centered on the peak that exceeds the threshold; a band-limiting filter selection unit that receives the peak pulse and the input signal for a length of the tap coefficient centered on the peak that exceeds the threshold, and outputs a suppressed peak pulse, 2. The peak suppression device according to claim 1, wherein the output signal is generated by combining the delayed input signal and the suppressed peak pulse.

5. the band-limiting filter selection unit includes a plurality of the band-limiting filters and an EVM calculation unit connected to each of the band-limiting filters; 5. The peak suppression device according to claim 4, wherein the band-limiting filter selection unit selects the band-limiting filter by inputting the peak pulse to each of the band-limiting filters, and inputting the band-limited peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold to the EVM calculation unit.

6. A peak suppression method for outputting an output signal in which peaks are suppressed by changing tap coefficients of a band-limiting filter used for a peak pulse in accordance with an input signal, A peak suppression method in which the tap coefficients are determined by performing a process for making the tap coefficients and the input signal similar to each other at predetermined time intervals.

7. 7. The peak suppression method according to claim 6, wherein the process of making the tap coefficients similar to each other is a process of increasing the tap coefficients when a predetermined threshold is exceeded and decreasing the tap coefficients when the predetermined threshold is not exceeded.

8. a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak detection unit receives the input signal, the converted power, the length of the tap coefficient of the band-limiting filter, and the peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficient centered on the peak that exceeds the threshold; a peak pulse generating unit inputting a peak pulse time and the peak of the input signal exceeding the threshold value, and outputting the peak pulse; a band-limiting filter generating unit receives the peak pulse and the input signal having a length corresponding to the tap coefficient centered on the peak exceeding the threshold value, and generates the band-limiting filter; a band-limiting filter that passes the peak pulse and outputs a suppressed peak pulse; 7. The peak suppression method according to claim 6, wherein the output signal is generated by combining the delayed input signal with the peak pulse.

9. a delay unit that delays the input signal; a power conversion unit that converts the input signal into power; a peak pulse generating unit receives the input signal, the converted power, the length of the tap coefficient of the band-limiting filter, and a peak threshold, and outputs the time of the peak, the peak of the input signal that exceeds the threshold, and the input signal for the length of the tap coefficient centered on the peak that exceeds the threshold; a band-limiting filter selection unit receives the peak pulse and the input signal for a length of the tap coefficient centered on the peak exceeding the threshold, and outputs a suppressed peak pulse; 7. The peak suppression method according to claim 6, wherein the delayed input signal and the suppressed peak pulse are combined to produce the output signal.

10. the band-limiting filter selection unit includes a plurality of the band-limiting filters and an EVM calculation unit connected to each of the band-limiting filters; 10. The peak suppression method according to claim 9, wherein the band-limiting filter selection unit selects the band-limiting filter by inputting the peak pulse to each of the band-limiting filters, and inputting the band-limited peak pulse and the input signal for a length of the tap coefficient centered on the peak that exceeds the threshold to the EVM calculation unit.

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