JP7004879B2 - Receiver, control circuit, storage medium and received signal processing method - Google Patents

Description

The present disclosure relates to a receiving device, a control circuit, a storage medium, and a receiving signal processing method for receiving a radio signal.

In a wireless communication system, a receiving device may deteriorate reception performance by receiving a signal transmitted from a transmitting device and receiving intersymbol interference in a multipath in a propagation path. In addition, systems such as satellite communications that perform single-carrier transmission over a wide band can ignore the effects of frequency characteristics, group delay, etc., that the amplitude characteristics of devices such as bandpass filters cannot be regarded as uniform in the frequency axis direction. It disappears and may cause intersymbol interference as well as multipath. In addition, some wireless communication systems may generate non-linear distortion by amplifying the signal using the non-linear region of the amplifier to improve power efficiency, in addition to such linear distortion.

As a method of reducing the influence of these distortions by the receiving device, there is an adaptive equalization technique for estimating and compensating for distortions in the propagation path. When distortion in the propagation path, inverse characteristics of distortion, etc. can be expressed by a linear FIR (Finite Impulse Response) filter, an adaptive linear equalizer that adaptively compensates and demodulates the distortion in the band while estimating it. The reception performance can be improved. However, as described above, in some wireless communication systems, the influence of non-linear distortion cannot be ignored, and the receiving device receives a signal that is distorted beyond the range that can be expressed by the linear FIR filter. May deteriorate. In particular, when the PAPR (Peak to Average Power Ratio) increases due to the increase in modulation multi-value or depending on the parameters such as the roll-off filter, the influence of the non-linear distortion becomes larger, so that the non-linear distortion needs to be compensated.

To solve such a problem, Patent Document 1 discloses an adaptive nonlinear equalization technique using a vortera filter. The adaptive nonlinear equalizer of Patent Document 1 expresses the inverse function of the propagation path including the nonlinear distortion by the first-order and third-order FIR filters, and arranges each FIR filter in parallel to synthesize the output. Both linear distortion and non-linear distortion can be compensated.

Japanese Patent No. 6510438

However, according to the technique described in Patent Document 1, the ratio of the nonlinear distortion component contained in the received signal changes in the same system, it is not necessary to perform the nonlinear equalization, and it is sufficient to perform only the linear equalization. In that case, there is a problem that the performance is deteriorated. For example, in satellite communication between an orbiting satellite and a ground station, when the satellite is located at a low elevation angle, the SNR (Signal to Noise Ratio) cannot be secured because the atmospheric passage distance is long, and the operating SNR is low QPSK ( Use a low-value transmission method such as Quadrature Phase Shift Keying). On the other hand, since SNR can be secured when the satellite is located at a high elevation angle, control called VCM (Variable Code and Modulation) such as high-value transmission such as 32APSK (Amplitude and Phase Shift Keying) may be performed. be. Further, in the terrestrial communication system, there is a similar mechanism for selecting the modulation method according to the state of the channel.

In such a case, the effect of nonlinear equalization can be obtained for high-value transmission with a large PAPR because the effect of nonlinear distortion is large, but the effect of nonlinear distortion is small for low-value transmission with a small PAPR. Therefore, sufficient compensation performance can be obtained only by linear equalization. Therefore, the non-linear equalization method having a large number of FIR filters deteriorates in performance.

The present disclosure has been made in view of the above, and obtains a receiving device capable of suppressing deterioration of demodulation performance in an equalization process in which distortion of a received signal is suppressed and demodulated by using a plurality of FIR filters. The purpose.

In order to solve the above-mentioned problems and achieve the object, the present disclosure is a receiving device in a wireless communication system in which the distortion characteristic of a received signal changes with time. The receiving device has an equalization processing unit that performs equalization processing of the received signal, a demapping unit that demaps the received signal after the equalization processing acquired from the equalization processing unit, and a demapping process acquired from the demapping unit. A signal information identification unit that identifies information indicating a distortion state of the received signal based on the result and generates signal identification information is provided. The equalization processing unit includes a plurality of equalization filter units connected in parallel, a filter switch control unit that switches whether to combine filter outputs from a plurality of equalization filter units based on signal identification information, and a filter switch control unit. It is characterized by comprising a filter coefficient synthesizing unit for synthesizing the filter coefficients of a plurality of equalization filter units based on signal identification information.

The receiving device according to the present disclosure has an effect that deterioration of demodulation performance can be suppressed in an equalization process in which distortion of a received signal is suppressed and demodulated by using a plurality of FIR filters.

The figure which shows the structural example of the receiving apparatus which concerns on Embodiment 1. The figure which shows the structural example of the filter coefficient synthesis part which concerns on Embodiment 1. A flowchart showing the operation of the receiving device according to the first embodiment. The figure which shows the structural example of the receiving apparatus which concerns on Embodiment 2. The figure which shows the structural example of the receiving apparatus which concerns on Embodiment 3. The figure which shows the structural example of the frame received by the receiving apparatus which concerns on Embodiment 3. The figure which shows the structural example of the processing circuit in the case where the processing circuit provided in the receiving apparatus which concerns on Embodiment 1 to Embodiment 3 is realized by a processor and a memory. The figure which shows the example of the processing circuit in the case where the processing circuit provided in the receiving device which concerns on Embodiment 1 to Embodiment 3 is configured by the dedicated hardware.

Hereinafter, the receiving device, the control circuit, the storage medium, and the received signal processing method according to the embodiment of the present disclosure will be described in detail with reference to the drawings. It should be noted that this embodiment is not limited to this disclosure.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of the receiving device 100 according to the first embodiment. The receiving device 100 receives a signal transmitted from a transmitting device (not shown) in a wireless communication system in which the distortion characteristic of the received signal changes with time. The receiving device 100 includes a receiving antenna 101, an RF (Radio Frequency) circuit unit 102, a timing control unit 103, a frequency control unit 104, an equalization processing unit 105, a timing estimation unit 106, and a frequency estimation unit 107. , A demapping unit 108, an error correction unit 109, a reference signal generation unit 110, and a signal information identification unit 111. The equalization processing unit 105 includes a first equalization filter unit 112, a second equalization filter unit 113, a filter coefficient setting unit 114, a filter coefficient synthesis unit 115, a filter switch control unit 116, and a switch 117. It is equipped with an adder 118.

The receiving antenna 101 receives a radio signal from the transmitting device via the propagation path. The receiving antenna 101 outputs the received signal to the RF circuit unit 102. The RF circuit unit 102 down-converts the received signal acquired from the receiving antenna 101 and converts it into a received signal in the baseband region. The RF circuit unit 102 may have an A / D (Analog / Digital) converter, generates a received signal in the baseband region based on various frequency conversion techniques, and outputs the received signal to the timing control unit 103. ..

The timing control unit 103 performs sampling value interpolation processing, resampling processing including upsampling or downsampling, and the like so that the received signal in the baseband region acquired from the RF circuit unit 102 has a predetermined oversampling ratio. And control at least one of the symbol timing and sampling clock of the received signal. The timing control unit 103 uses timing control information such as timing phase information generated by the timing estimation unit 106. The timing control unit 103 outputs the received signal after the timing control to the frequency control unit 104.

The frequency control unit 104 performs frequency control, that is, frequency correction of the received signal, based on the estimation result of the frequency deviation generated by the frequency estimation unit 107. The frequency control unit 104 outputs the received signal after frequency correction to the equalization processing unit 105. Although omitted in FIG. 1, the frequency control unit 104 may output the frequency-corrected received signal to the timing estimation unit 106 and the frequency estimation unit 107.

The equalization processing unit 105 uses the reference signal acquired from the reference signal generation unit 110 and the signal identification information indicating the distortion state of the received signal acquired from the signal information identification unit 111 to perform adaptive equalization processing, that is, a frequency control unit. An equalization process suitable for the received signal acquired from 104 is performed. The equalization processing unit 105 outputs the received signal after the equalization processing to the timing estimation unit 106, the frequency estimation unit 107, and the demapping unit 108.

The timing estimation unit 106 estimates the deviation of the sampling clock due to the clock deviation between the transmission device and the reception device 100, and generates timing phase information indicating the estimation result. The timing estimation unit 106 outputs the generated timing phase information to the timing control unit 103. As a result, the receiving device 100 can follow the clock deviation from the transmitting device by performing sampling value interpolation processing, resampling processing, and the like on the received signal by the timing control unit 103. As a method for estimating the deviation of the sampling clock by the timing estimation unit 106, the equalization processing unit 105 is used for the received signal before the equalization processing acquired from the frequency control unit 104, or when a delay until the timing control can be tolerated. There is a method of using a correlation process with a known signal, a multiplication tank method, or the like for the received signal after the equalization process obtained from the above. Further, when the oversampling rate is insufficient to achieve the desired timing phase estimation accuracy, the timing estimation unit 106 improves the estimation accuracy or the resolution by performing the above processing after performing the upsampling processing. Is possible. Further, the timing estimation unit 106 may perform timing control so as to reduce the approximation error due to the filter coefficient synthesis processing in the filter coefficient synthesis unit 115.

The frequency estimation unit 107 estimates the frequency deviation based on the received signal after the equalization processing acquired from the equalization processing unit 105 or the received signal before the equalization processing acquired from the frequency control unit 104, and estimates the estimation result. It feeds back to the frequency control unit 104. The frequency estimation unit 107 may estimate the frequency deviation by using the reference signal obtained by hard-determining the received signal, for example, by using the adaptive filter processing by the 1-tap LMS (Least Mean Square). Then, the phase difference between the reference signal and the received signal may be averaged by an IIR (Infinite Impulse Response) filter or the like to follow the phase rotation and estimate the frequency deviation. Further, when the received signal includes a pilot signal which is a known signal, the frequency estimation unit 107 may observe the amount of phase rotation between the pilot signals and estimate the frequency deviation.

The demapping unit 108 demaps the received signal after the equalization processing acquired from the equalization processing unit 105. Specifically, the demapping unit 108 demapping the received signal after the equalization processing, such as soft determination processing, hard determination processing, and deinterleave processing, which are necessary for the error correction unit 109 to perform error correction. Perform processing. When performing the hard determination process in the demapping process, the demapping unit 108 may use synchronous detection having high noise resistance performance or may use a detection method resistant to fluctuations such as delayed detection if the synchronization performance is sufficient. .. The demapping unit 108 outputs the demapping processing result to the error correction unit 109, the reference signal generation unit 110, and the signal information identification unit 111.

The error correction unit 109 performs error correction using an error correction code based on the demapping processing result acquired from the demapping unit 108, and outputs it as a decoding result. Further, the error correction unit 109 determines whether or not the signal has been correctly decoded by using a checksum or the like, and outputs a re-encoded data string of the signal determined to be correctly decoded to the reference signal generation unit 110. Although the error correction unit 109 is omitted in FIG. 1, the above-mentioned data string may be output to the signal information identification unit 111.

The reference signal generation unit 110 generates a reference signal used by the equalization processing unit 105 to perform the equalization processing. Specifically, the reference signal generation unit 110 performs mapping based on at least one of the demapping process result acquired from the demapping unit 108 and the recoded data string acquired from the error correction unit 109. , Convert to a reference signal. The reference signal generation unit 110 outputs the generated reference signal to the filter coefficient setting unit 114 of the equalization processing unit 105. When a known signal such as a pilot signal or a preamble is included in the received signal, the reference signal generation unit 110 may use the known signal as it is as a reference signal.

The signal information identification unit 111 identifies information indicating a distortion state of the received signal based on the demapping processing result acquired from the demapping unit 108, and generates signal identification information. As information indicating the distortion state of the received signal, the signal identification information includes the modulation method of the received signal, the coding rate of the received signal, PAPR, that is, the peak-to-average power ratio of the received signal, and the transmission device which is the source of the received signal. The second equalization filter unit 113 is used in the equalization processing unit 105 such as amplifier operation backoff, signal quality such as received SNR, that is, signal-to-noise ratio of the received signal, position information of the transmitting device, and position information of the receiving device 100. Contains information to determine whether or not. The signal identification information does not have to include all of the above-mentioned information, and may include at least one. The signal information identification unit 111 outputs the signal identification information to the filter coefficient synthesis unit 115 and the filter switch control unit 116 of the equalization processing unit 105.

The configuration of the equalization processing unit 105 will be described in detail. The first equalization filter unit 112 and the second equalization filter unit 113 are FIR type digital filters that are connected in parallel and perform a convolution operation between the received signal and the filter coefficient. The first equalization filter unit 112 and the second equalization filter unit 113 are, for example, filters of memory polynomials using a vortera filter. The first equalization filter unit 112 and the second equalization filter unit 113 are, for example, a first-order filter component and a third-order filter component of the vortera filter. The voltera filter output of the k-th symbol equalized only by the first-order filter component and the third-order filter component is expressed by the equation (1).

In the equation (1), y (t) is the received signal acquired by the equalization processing unit 105, h ₁ (t) is the filter coefficient of the first equalization processing unit, and h ₃ (t) is the filter of the second equalization processing unit. Corresponding to the coefficient, the filter lengths of the first equalization filter unit 112 and the second equalization filter unit 113 are represented by M, and the number of oversamples is represented by P. In the example of FIG. 1, the equalization processing unit 105 shows only the first-order filter component and the third-order filter component in the first equalization filter unit 112 and the second equalization filter unit 113. Voltera filters of different orders may be arranged in parallel, or FIR filters other than the Voltera filter may be arranged in parallel. For example, in order to reduce the amount of calculation, the equalization processing unit 105 may configure a plurality of equalization filters with components based on the memory polynomial shown in the equation (2). When the memory polynomials of the first-order filter component and the third-order filter component are used for the first equalization filter unit 112 and the second-order equalization filter unit 113, respectively, the first term of the equation (2) becomes the first-order filter component. The second term corresponds to the third-order filter component.

The first equalization filter unit 112 and the second equalization filter unit 113 each shift the received signal to the shift register constituting the FIR filter at a time by the number of oversamples, so that the output of the 1x oversample is obtained. Can be converted to. Further, the first equalization filter unit 112 and the second equalization filter unit 113 can be output in an oversampled state by shifting to the shift register one sample at a time.

In the following, in order to realize non-linear equalization for equalizing the non-linear distortion of the received signal, the first equalization filter unit 112 performs the processing of the first term corresponding to the first-order component of the above-mentioned memory polynomial. It will be described as assuming that the equalization filter unit 113 performs the processing of the second term corresponding to the cubic component of the memory polynomial described above. In this case, the first equalization filter unit 112 serves as an equalization filter unit for equalizing the linear distortion of the received signal, and the second equalization filter unit 113 performs the equalization processing of the non-linear distortion of the received signal. It becomes the equalization filter part of.

The filter switch control unit 116 switches whether or not to combine the filter outputs from the first equalization filter unit 112 and the second equalization filter unit 113 based on the signal identification information acquired from the signal information identification unit 111. Specifically, the filter switch control unit 116 controls the switch 117 based on the signal identification information to control whether or not the output of the second equalization filter unit 113 is connected to the adder 118. The received signal after the equalization processing output from the equalization processing unit 105 is generated by the sum of the filter output of the first equalization filter unit 112 and the filter output of the second equalization filter unit 113. Here, when the nonlinear distortion component of the received signal is small, for example, in the case of a constant envelope signal such as QPSK or 8PSK, it is better to use only the filter output of the first equalization filter unit 112 corresponding to the linear equalization process. The reception performance of the receiving device 100 may be improved. In addition, when sufficient nonlinear distortion compensation is performed using DPD (Digital Pre-Distortion), Linearier, etc. that compensate for the nonlinear distortion of the amplifier in the transmitter, the line margin is large and the input backoff of the amplifier is large. Even when it is possible to take it and use it mainly in the linear region of the amplifier, the effect of nonlinear distortion may be negligible. In such a case, in the equalization processing unit 105, the filter switch control unit 116 turns off the switch 117 so as not to use the filter output of the second equalization filter unit 113. As a result, the equalization processing unit 105 can reduce the number of filter coefficients to be estimated in the adaptive equalization, improve the followability, improve the filter coefficient estimation accuracy, and improve the reception performance.

The switch 117 switches whether or not to combine the filter output of the first equalization filter unit 112 and the filter output of the second equalization filter unit 113 under the control of the filter switch control unit 116. When the switch 117 is turned on by the control of the filter switch control unit 116, the switch 117 outputs the filter output of the second equalization filter unit 113 to the adder 118. When the switch 117 is turned off by the control of the filter switch control unit 116, the switch 117 does not output the filter output of the second equalization filter unit 113 to the adder 118.

When the adder 118 acquires the filter output of the second equalization filter unit 113 from the switch 117, the adder 118 adds the filter output of the second equalization filter unit 113 to the filter output of the first equalization filter unit 112 and equalizes them. Output as a received signal after processing. When the adder 118 has not acquired the filter output of the second equalization filter unit 113 from the switch 117, the adder 118 outputs the filter output of the first equalization filter unit 112 as a received signal after the equalization process.

The filter coefficient setting unit 114 sets the filter coefficient used in the first equalization filter unit 112 and the second equalization filter unit 113. As a method of setting the filter coefficient in the filter coefficient setting unit 114, for example, it is conceivable to set the filter coefficient using the received signal acquired from the frequency control unit 104. The filter coefficient setting unit 114 performs propagation path estimation using a known signal portion included in the received signal, and estimates the inverse characteristic of the propagation path estimation result by an inverse matrix operation or the like, whereby the first equalization filter unit 112 and The initial value of the filter coefficient of either or both of the second equalization filter unit 113 can be determined. When sufficient accuracy cannot be obtained, such as when the number of known signals is small compared to the number of filter coefficients to be estimated, the filter coefficient setting unit 114 calculates the filter coefficient of only one of the equalization filter units. The initial value of the filter coefficient of the other equalization filter unit may be 0 or a predetermined value. The filter coefficient setting unit 114 may use a blind tap coefficient estimation method such as CMA (Constant Modulus Algorithm) that does not require a known signal.

Further, the filter coefficient setting unit 114 uses the received signal acquired from the frequency control unit 104, the reference signal acquired from the reference signal generation unit 110, and the filter coefficient of each equalization filter unit as other filter coefficient setting methods. Then, the filter coefficient may be updated sequentially by the adaptive algorithm. As the adaptive algorithm, for example, LMS, RLS (Recursive Least Square) and the like can be applied. Further, the filter coefficient setting unit 114 can also set the filter coefficient of each equalization filter unit acquired from the filter coefficient synthesis unit 115 described later in the corresponding equalization filter unit as it is.

The filter coefficient synthesizing unit 115 reads the filter coefficient set by the filter coefficient setting unit 114 in the first equalization filter unit 112 and the second equalization filter unit 113, and uses the signal identification information acquired from the signal information identification unit 111. Based on this, the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113 are combined as necessary. The filter coefficient synthesis unit 115 outputs the combined filter coefficient to the filter coefficient setting unit 114. The detailed configuration of the filter coefficient synthesizing unit 115 will be described. FIG. 2 is a diagram showing a configuration example of the filter coefficient synthesizing unit 115 according to the first embodiment. The filter coefficient synthesis unit 115 includes a synthesis coefficient determination unit 119 and a coefficient selector unit 120. When synthesizing the filter coefficients, the synthesis coefficient determination unit 119 determines a value to be multiplied by each filter coefficient, and instructs the coefficient selector unit 120 to select a filter coefficient to be newly used. Based on the selection instruction of the synthesis coefficient determination unit 119, the coefficient selector unit 120 uses the acquired filter coefficient as the filter coefficient of the new first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113, that is, after synthesis. It is output as the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113 after synthesis.

The signal information identification unit 111 is in a state where the equalization processing unit 105 synthesizes the filter output of the first equalization filter unit 112 and the filter output of the second equalization filter unit 113 to perform equalization processing for removing distortion. When the switch 117 is switched from on to off by the filter switch control unit 116 based on the signal identification information acquired from, only the first equalization filter unit 112 is used as the received signal output from the equalization processing unit 105. The characteristics are more likely to deteriorate than in the case of linear equalization processing. This is the filter coefficient when the filter coefficient is close to the optimum solution on the premise that multiple equalization filter units are parallelized and the equalization processing is performed, and the filter coefficient on the premise that the equalization processing is performed by one equalization filter unit. This is due to the fact that the obtained filter coefficient is different from the filter coefficient when is close to the optimum solution. As a countermeasure to such a problem, the filter coefficient synthesizing unit 115 uses the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113 as the signal identification information acquired from the signal information identification unit 111. Based on this, it is synthesized and output as the filter coefficient of the new first equalization filter unit 112 or the filter coefficient of the new second equalization filter unit 113. At this time, the filter coefficient synthesizing unit 115 can reset each filter coefficient by multiplying it by 0, or by holding the filter coefficient as it is, the convergence speed when the switch 117 is turned on next time. Can also be accelerated.

A specific example of a method for determining the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113 in the equalization processing unit 105 will be described. For example, assuming that the received signal is a constant envelope signal and the average power is 1, the absolute value portion of the second term in the equation (2) can be approximated to 1. In such a case, h ₁ (m) and h ₃ (m) are filter coefficients for the same received signal. Therefore, the equalization processing unit 105 sets the filter coefficient of the first equalization filter unit 112 to h ₁ (m) + h ₃ (m) and the filter coefficient of the second equalization filter unit 113 to 0 to set the first equalization filter. If only the unit 112 is used, linear equalization can be realized with a small filter coefficient ignoring the influence of the filter coefficient of the second equalization filter unit 113, and improvement in reception performance can be expected. Further, when the equalization processing unit 105 switches to linear equalization only because the effect of the non-linear equalization is small or the convergence does not go well even during multi-value modulation, the first equalization filter unit 112 Set the filter coefficient to αh ₁ (m) + βh ₃ (m), set the filter coefficient of the second equalization filter unit 113 to 0, weight α and β for synthesis, and use only the first equalization filter unit 112. It is also possible to shift to linear equalization.

When performing fractional interval equalization, the equalization processing unit 105 approximates the absolute value portion of the second term in the equation (2) to 1 depending on the timing phase of the sampling clock even if the received signal is a constant envelope signal. May be difficult. In this case, the timing estimation unit 106 sets the timing phase of the sampling clock of the received signal so that the approximation error becomes small. Specifically, the timing estimation unit 106 brings the symbol timing and the timing phase of the sampling clock as close as possible. It is also conceivable to reduce the approximation error by obtaining such an estimated value.

The receiving device 100 can also include a plurality of equalization filter units, that is, three or more equalization filter units. In this case, the receiving device 100 includes a plurality of switches 117, which is one less than the number of equalization filter units. In the receiving device 100, the filter switch control unit 116 controls the on / off of each switch 117 to control the use of the filter output from the plurality of equalization filter units.

FIG. 3 is a flowchart showing the operation of the receiving device 100 according to the first embodiment. When the receiving device 100 receives the signal, the receiving device 100 performs a synchronization process with the received signal (step S101). In the synchronous processing, first, the frequency control unit 104 and the timing control unit 103 convert the received signal into the assumed frequency and sample timing based on the estimation results of the frequency estimation unit 107 and the timing estimation unit 106. Then, the filter coefficient setting unit 114 sets the filter coefficient of either or both of the first equalization filter unit 112 and the second equalization filter unit 113 using the received signal converted to the assumed frequency and sample timing. Then, the demapping unit 108 and the signal information identification unit 111 are in an operable state.

The signal information identification unit 111 identifies information indicating a distortion state of the received signal based on the demapping processing result acquired from the demapping unit 108 (step S102). As described above, the information indicating the distortion state of the received signal includes the modulation method of the received signal, the coding rate of the received signal, PAPR, that is, the peak-to-average power ratio of the received signal, and the transmission device which is the source of the received signal. The second equalization filter unit 113 is used in the equalization processing unit 105 such as amplifier operation backoff, signal quality such as received SNR, that is, signal-to-noise ratio of the received signal, position information of the transmitting device, and position information of the receiving device 100. It is information for deciding whether or not. The signal information identification unit 111 generates signal identification information and outputs the signal identification information to the filter coefficient synthesis unit 115 and the filter switch control unit 116 of the equalization processing unit 105.

Whether or not the filter switch control unit 116 and the synthesis coefficient determination unit 119 of the filter coefficient synthesis unit 115 use the filter output of the second equalization filter unit 113 based on the signal identification information acquired from the signal information identification unit 111. That is, the control for the switch 117 that outputs the filter output of the second equalization filter unit 113 is determined (step S103). At this time, the equalization processing unit 105 operates differently depending on whether the switch 117 remains on or off, from on to off, or from off to on.

As an example of making a judgment from on to off from a modulation method, for example, when the modulation method is changed from a high-value modulation method such as 16APSK to a low-value modulation method such as 8PSK, the influence of nonlinear distortion is Considering that it becomes smaller, it is conceivable to turn off the second equalization filter unit 113. In this case, in the equalization processing unit 105, in order to alleviate the deterioration of the characteristics when the switch 117 is switched off, the filter coefficient synthesis unit 115 is the filter of the first equalization filter unit 112 and the second equalization filter unit 113. The coefficient is read, the filter coefficient is synthesized based on the signal identification information (step S104), and is output to the filter coefficient setting unit 114. That is, in the filter coefficient synthesizing unit 115, at least one equalization filter is performed by the filter switch control unit 116 from the state where the equalization processing unit 105 sets the filter coefficients in the plurality of equalization filter units and performs the equalization processing. When the filter output of is turned off, the filter coefficients set in the plurality of equalization filter units are multiplied and combined, and the equalization filter coefficients are newly set in the plurality of equalization filter units. For example, the filter coefficient synthesis unit 115 is set in a plurality of equalization filter units when it recognizes that the modulation method of the received signal has been switched from the non-envelope signal to the constant envelope signal based on the signal identification information. Synthesize the filter coefficients. The filter coefficient setting unit 114 sets the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113. After that, the filter switch control unit 116 turns off the switch 117 for switching the on / off of the filter output of the second equalization filter unit 113 (step S105).

As an example of making a decision from off to on from a modulation method, for example, when the modulation method is changed from a low-value modulation method such as 8PSK to a high-value modulation method such as 16APSK, the influence of nonlinear distortion is affected. It is conceivable to turn on the second equalization filter unit 113 in consideration of the increase (step S106). In this case, if the equalization processing unit 105 clears the initial value of the second equalization filter unit 113 to 0 before switching the switch 117 on, the switch 117 of the second equalization filter unit 113 is turned on. It is possible to alleviate the deterioration of the characteristics when the switch 117 is switched. Alternatively, if the channel does not change and the filter coefficient of the second equalization filter unit 113 used last time can be continuously used, the equalization processing unit 105 has the filter coefficient of the second equalization filter unit 113. It is also conceivable to turn on the switch 117 for switching the on / off of the second equalization filter unit 113 without resetting. That is, in the filter coefficient synthesizing unit 115, the filter switch control unit 116 sets another equalization filter from the state in which the equalization processing unit 105 sets the filter coefficient in at least one equalization filter unit and performs the equalization processing. When the filter output of the unit changes from off to on, the filter coefficient of the equalization filter unit whose filter output has changed to on is set to a predetermined value.

As an example of making a judgment from the modulation method to remain on, that is, from on to on, or to remain off, that is, from off to off, for example, when the modulation method is not changed, the non-linearity of the received signal is large. It is possible that the value does not change.

The equalization processing unit 105 starts the equalization processing after leaving the on / off of the switch 117 as it is or switching the on / off of the switch 117 as necessary (step S107). After the equalization process, the receiving device 100 returns to the operation of step S102 again at the specified timing. The specified timing may be between frames where the modulation scheme is expected to change, or the positional relationship between the transmitting device and the receiving device 100, for example, a satellite if it is a communication between satellite ground stations. It may be the timing at which the signal performance is expected to change depending on the elevation angle and the like. In addition, it is also possible to measure while receiving PAPR, SNR, etc., and perform these operations according to the measurement result.

The receiving device 100 may include a storage unit that stores the demodulation result generated by the error correction unit 109, or is generated by the error correction unit 109 as a result of the equalization processing by the equalization processing unit 105. A display unit capable of displaying a demodulation result or the like may be provided. Further, another device (not shown) connected to the receiving device 100 may include the above-mentioned storage unit and display unit.

As described above, according to the present embodiment, when the distortion of the received signal is equalized by a plurality of equalization filters, the receiving device 100 is in a state of distortion of the received signal to be equalized. The use of each equalization filter unit was decided accordingly, and the filter coefficients were selected or synthesized when switching the use. As a result, the receiving device 100 can realize a highly accurate distortion compensation effect even in a system in which the distortion state of the received signal changes. Further, since the receiving device 100 does not provide a separate equalization filter unit, it is also effective in that an increase in the circuit scale can be suppressed.

Embodiment 2.
In the first embodiment, the frequency estimation unit 107 and the timing estimation unit 106 perform estimation using the received signal after the equalization processing by the equalization processing unit 105. In the second embodiment, the case where the frequency estimation unit 107 and the timing estimation unit 106 perform estimation using the received signal equalized by the equalization filter unit different from the equalization processing unit will be described.

FIG. 4 is a diagram showing a configuration example of the receiving device 200 according to the second embodiment. In the receiving device 200, the equalization processing unit 105 is replaced with the equalization processing unit 205, and the third equalization filter unit 201 is added to the receiving device 100 of the first embodiment shown in FIG. The equalization processing unit 205 replaces the filter coefficient synthesis unit 115 with the filter coefficient synthesis unit 215 with respect to the equalization processing unit 105 of the first embodiment shown in FIG.

The third equalization filter unit 201 is a filter that performs equalization processing for timing estimation by the timing estimation unit 106 and frequency estimation by the frequency estimation unit 107, and generates a received signal after the equalization processing. The third equalization filter unit 201 may generate a received signal after equalization processing for at least one of the timing estimation by the timing estimation unit 106 and the frequency estimation by the frequency estimation unit 107.

The filter coefficient synthesizing unit 215 has a function of setting a filter coefficient in the third equalization filter unit 201 in addition to the function of the filter coefficient synthesizing unit 115 of the first embodiment shown in FIG.

The receiving device 200 has the filter coefficient of the first equalization filter unit 112 and the second equalization filter unit 113 for the residual deviation that cannot be followed by the timing estimation by the timing estimation unit 106 and the frequency estimation by the frequency estimation unit 107. It is supposed to be applied to an environment where it is necessary to follow while updating the filter coefficient with an adaptive algorithm or the like. In such an environment, the result of following the sample timing error, frequency error, etc. by the adaptive algorithm is fed back to the frequency estimation unit 107 and the timing estimation unit 106. Therefore, it is conceivable that a plurality of feedback loops will be generated, it will be difficult to guarantee the stability, and the estimation error will not be reduced by interfering with each other.

In the present embodiment, the receiving device 200 includes a third equalization filter unit 201 that performs equalization processing for the timing estimation unit 106 and the frequency estimation unit 107. The third equalization filter unit 201 performs an equalization process in which the filter coefficient is fixed by the filter coefficient set by the filter coefficient synthesis unit 215. As a result, the frequency estimation unit 107 and the timing estimation unit 106 do not receive feedback from the tracking by the adaptive algorithm in the first equalization filter unit 112 and the second equalization filter unit 113, which not only facilitates control but also facilitates control. The estimation accuracy will also be improved.

Here, the receiving device 200 reads the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113, and sets each filter coefficient to the third equalization filter unit 201 and a fourth not shown. A configuration in which an equalization filter unit is provided and the equalization processing for the timing estimation unit 106 and the frequency estimation unit 107 is performed by synthesizing these filter outputs is also conceivable. However, in such a configuration, the circuit scale of the receiving device 200 becomes large.

Therefore, the receiving device 200 uses the filter coefficient synthesized by the filter coefficient synthesizing unit 215, and constitutes the third equalization filter unit 201 with one FIR filter. Assuming that the frequency estimation unit 107 and the timing estimation unit 106 perform estimation processing on the known signal included in the received signal and the known signal is a constant inclusion signal, the filter coefficient synthesis unit 215 is equalized. By providing the result of synthesizing the filter coefficient of the filter unit 112 and the filter coefficient of the second equalization filter unit 113 to the third equalization filter unit 201, one FIR filter can perform equalization processing for frequency and timing control. realizable.

However, if the same filter coefficient is continuously used, the error of the output signal of the third equalization filter unit 201 becomes large due to the clock deviation, and the frequency estimation error and the timing estimation error become large. Therefore, the filter coefficient synthesizing unit 215 periodically reads and synthesizes the filter coefficient set in the first equalization filter unit 112 and the filter coefficient set in the second equalization filter unit 113, and synthesizes them. A filter coefficient to be set in the filter unit 201 is generated. The filter coefficient synthesis unit 215 sets, that is, provides the generated filter coefficient in the third equalization filter unit 201. The period in which the filter coefficient synthesizing unit 215 provides the filter coefficient to the third equalization filter unit 201 may be a predetermined number of samples, a period including the frame head, a known signal, or the like, or the like. The timing may be determined by the method of.

As described above, according to the present embodiment, the receiving device 200 is provided with a third equalization filter unit 201 for timing estimation and frequency estimation, and is separated from the equalization processing unit 205 updated by the adaptive algorithm. It was decided to. As a result, the receiving device 200 can realize highly accurate estimation by the frequency estimation unit 107 and the timing estimation unit 106 while following the slight residual deviation by the adaptive algorithm, and as a result, the reception performance of the receiving device 200 is improved. be able to. Further, the receiving device 200 synthesizes and provides the filter coefficient of the first equalization filter unit 112 and the filter coefficient of the second equalization filter unit 113 as the filter coefficient of the third equalization filter unit 201. It also has the effect of eliminating the need for a quaternization filter unit and reducing the circuit scale.

Embodiment 3.
In the third embodiment, a case where the propagation path between the transmitting device and the receiving device fluctuates at high speed will be described. The third embodiment is applicable to both the first embodiment and the second embodiment. Hereinafter, a case where the application is applied to the first embodiment will be described as an example.

FIG. 5 is a diagram showing a configuration example of the receiving device 300 according to the third embodiment. The receiving device 300 is intended to be used in a wireless communication system in which a burst signal that is discontinuous in time arrives. The receiving device 300 replaces the equalizing processing unit 105 with the equalizing processing unit 305 with respect to the receiving device 100 of the first embodiment shown in FIG. The equalization processing unit 305 includes a buffer unit 301, a selective composition unit 302, a first equalization filter unit 312, a second equalization filter unit 313, a filter coefficient setting unit 314, and a filter coefficient synthesis unit 315. A filter switch control unit 316 is provided. The receiving device 300 is an effective configuration when applied to a high-speed fluctuation environment in which the fluctuation component to be compensated for the received signal exceeds the tracking capability of the adaptive algorithm. The filter coefficient synthesizing unit 315 can also add the function of the filter coefficient synthesizing unit 215 described in the receiving device 200. In this case, the equalization processing unit 205 of the receiving device 200 shown in FIG. 4 may be replaced with the equalization processing unit 305.

The third embodiment assumes a system in which a set of known SW (Sync Word) and payload as shown in FIG. 6 is set as one frame, and a certain number of multiple frames arrive in a burst. FIG. 6 is a diagram showing a configuration example of a frame received by the receiving device 300 according to the third embodiment. Further, in the third embodiment, the propagation path fluctuates at high speed due to the transmission device, the reception device 300, or both moving at high speed, and the determination-oriented adaptive algorithm as described in the first and second embodiments is performed. Then, we assume an environment where it is difficult to follow. As the fluctuation factor, for example, not only frequency deviation and clock deviation but also multipath fading and the like can be considered, and a case where these high-speed fluctuations are processed by cumulative batch demodulation is considered.

The buffer unit 301 receives timing control by the timing control unit 103 and frequency control by the frequency control unit 104, and stores the received signal acquired from the frequency control unit 104. The buffer unit 301 outputs the received signal to the first equalization filter unit 312, the second equalization filter unit 313, and the filter coefficient setting unit 314 at the specified timing. Specifically, the buffer unit 301 controls the read address in order to perform the equalization for channel estimation and the equalization for demodulation using the tentative determination value in a time division manner. Here, it is assumed that the received signal acquired by the buffer unit 301 from the frequency control unit 104 has a fluctuation speed to which the propagation path fluctuation can be ignored within the known symbol.

Further, when the receiving device 300 receives one transmission signal with two receiving antennas and performs equalization processing corresponding to each receiving antenna, the first equalization filter unit 312 receives the reception signal of the first receiving antenna. It is also conceivable that the second equalization filter unit 313 performs the equalization processing of the reception signal of the second receiving antenna. As shown in FIG. 5, when the receiving device 300 receives the transmission signal by one receiving antenna 101 and performs the equalization processing by the two equalization filter units, the first class is the same as the receiving devices 100 and 200. The equalization filter unit 312 and the second equalization filter unit 313 perform equalization processing on the same received signal.

In order to cope with high-speed fluctuation of the received signal, the buffer unit 301 can rewind the read address at an appropriate timing instead of continuously outputting the received signal. Specifically, the buffer unit 301 estimates the filter coefficient of the equalization filter unit from a plurality of reference signals, performs equalization processing and demodulation for channel estimation, and then sets the read address to half the reference signal length. The received signal for equalization processing for rewinding and demodulation is output. That is, by using the reference signal once tentatively determined for the calculation of the filter coefficient, the receiving device 300 can calculate the filter coefficient using the past and future reference signals centering on the symbol to be equalized, which is faster. It is possible to follow the propagation path fluctuation.

Further, when the received signal is difficult to demodulate due to a momentary decrease in SNR due to fading and the subsequent determination process is adversely affected by error propagation, the buffer unit 301 reversely reproduces the read pointer and actually reproduces the read pointer. By performing equalization processing in the reverse order of the reception time, it is conceivable to eliminate the phenomenon that the subsequent determination results continue to be erroneous due to a momentary drop in SNR.

If the first equalization filter unit 312 and the second equalization filter unit 313 perform equalization processing on the signal obtained from one received signal with a plurality of filters, as described above, the vortera filter can also be used. It may be a linear component and a cubic component of a memory polynomial, or it may be configured such that two linear filters having different methods of obtaining filter coefficients are arranged side by side. Further, when the first equalization filter unit 312 and the second equalization filter unit 313 receive one transmission signal by two receiving antennas and perform equalization processing corresponding to each receiving antenna, the transmitting antenna and each are performed. It may be two linear filters that represent the reverse characteristics of the propagation path to and from the receiving antenna.

The filter coefficient setting unit 314 has the same function as the filter coefficient setting unit 114, and further, the inverse characteristic of the propagation path is obtained by using the received signal acquired from the buffer unit 301 and the reference signal acquired from the reference signal generation unit 110. It has a function to calculate and set it in the first equalization filter unit 312 and the second equalization filter unit 313. At this time, the filter coefficient setting unit 314 may calculate the inverse characteristic of the direct propagation path by an inverse matrix operation, or may identify the propagation path once and then convert it into the inverse characteristic. Further, when the receiving device 300 receives one transmission signal by two receiving antennas and performs the equalization processing corresponding to each receiving antenna, the filter coefficient setting unit 314 estimates the propagation path for each equalizing filter unit. The estimation process of the reverse characteristic of the propagation path is performed.

The selective synthesis unit 302 is controlled by the filter switch control unit 316, and the filter output of the first equalization filter unit 312, the filter output of the second equalization filter unit 313, or the filter output of the first equalization filter unit 312 and The combined value of the filter output of the second equalization filter unit 313 is output as a received signal after the equalization processing. Although not shown in the figure, when synthesizing the filter output of the first equalization filter unit 312 and the filter output of the second equalization filter unit 313, they are combined after multiplying by a coefficient in either one. By doing so, it is possible to suppress the deterioration of accuracy when the equalization output accuracy of one of them is poor. As a method for determining the coefficient at the time of synthesis, a coefficient determination method based on the instantaneous power of the signal input to each equalization filter unit, the moving average value thereof, and the like can be considered. Alternatively, the likelihood information may be obtained from the equalized output result, and this result may be fed back to determine the coefficient. By multiplying such a coefficient, a coefficient with a small amplitude is multiplied for the equalized output result with low equalization accuracy, and a coefficient with a large amplitude is multiplied for the equalized output result with high equalization accuracy. It is possible to obtain with high accuracy. As another selective synthesis method, the SW that arrives next to the payload being demodulated is demodulated, the demodulated result is compared with the true value of the SW, and selection or synthesis is performed depending on how much the demodulation is mistaken. May be good. For example, in the case of an equalization filter unit that can demodulate SW without error and an equalization filter unit that demodulates about half by mistake, a method such as adopting only the output result of the equalization filter unit that can demodulate without error is adopted. Conceivable. Alternatively, it may be synthesized after multiplying by a coefficient according to the error ratio.

The filter switch control unit 316 receives either one of the filter output of the first equalization filter unit 312 and the filter output of the second equalization filter unit 313, or the first one, based on the signal identification information acquired from the signal information identification unit 111. It is determined which of the combined value of the filter output of the equalizing filter unit 312 and the filter output of the second equalizing filter unit 313 is output as the received signal after the equalization processing, and the selective combining unit 302 is controlled. When the receiving device 300 receives one transmission signal with two receiving antennas and performs equalization processing corresponding to each receiving antenna, the first receiving antenna corresponding to the first equalization filter unit 312 undergoes fading. When the SNR is depressed and the SNR is not depressed in the second receiving antenna corresponding to the second equalization filter unit 313, only the output of the second equalization filter unit 313 can be used.

The filter coefficient synthesizing unit 315 has the same configuration as the filter coefficient synthesizing unit 115 of the receiving device 100, the filter coefficient synthesizing unit 215 of the receiving device 200, and the like. However, when the receiving device 300 receives one transmission signal with two receiving antennas and performs equalization processing corresponding to each receiving antenna, the correlation of the propagation path between the transmitting antenna and each receiving antenna is high. If the channel variability is high and almost the same, the filter coefficients may be combined or selected and only one filter coefficient may be used.

As described above, according to the present embodiment, the equalization processing unit 305 is equalized for channel estimation using a tentative determination value and for demodulation in order to cope with high-speed propagation path fluctuations. It was decided to control the read address in order to perform time division. As a result, the equalization processing unit 305 can follow high-speed propagation path fluctuations and can prevent an increase in circuit scale. Further, the equalization processing unit 305 makes it possible to realize a highly accurate distortion compensation effect even in a system in which the distortion state of the received signal changes by selecting or synthesizing the filter coefficient according to the state of the received signal.

Here, the hardware configurations of the receiving devices 100, 200, and 300 will be described. In the receiving devices 100, 200, and 300, the receiving antenna 101 and the RF circuit unit 102 are realized by the receiver. In the receiving devices 100, 200, 300, other configurations are realized by the processing circuit. The processing circuit may be a processor and memory for executing a program stored in the memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

FIG. 7 is a diagram showing a configuration example of a processing circuit 90 when the processing circuits included in the receiving devices 100, 200, and 300 according to the first to third embodiments are realized by a processor and a memory. The processing circuit 90 shown in FIG. 7 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program in which the processing of the receiving devices 100, 200, and 300 is to be executed as a result. It can be said that this program is a program for causing the receiving devices 100, 200, and 300 to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

In the above program, the equalization processing unit 105 demaps the equalization processing step of performing the equalization processing of the received signal, and the demapping unit 108 demaps the received signal after the equalization processing acquired from the equalization processing unit 105. A demapping step and a signal information identification step in which the signal information identification unit 111 identifies information indicating a distortion state of the received signal based on the demapping processing result acquired from the demapping unit 108 and generates signal identification information. , To the receiving devices 100, 200, 300, and in the equalization processing step, whether or not the filter switch control unit 116 synthesizes the filter outputs from the plurality of equalization filter units based on the signal identification information. It is also a program that causes the receiving devices 100, 200, and 300 to execute a control step for switching and a synthesis step in which the filter coefficient synthesizing unit 115 synthesizes the filter coefficients of a plurality of equalization filter units based on the signal identification information. I can say.

Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like. Further, the memory 92 may be non-volatile or volatile, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM), or the like. This includes semiconductor memory, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc), and the like.

FIG. 8 is a diagram showing an example of a processing circuit 93 in the case where the processing circuits included in the receiving devices 100, 200, and 300 according to the first to third embodiments are configured by dedicated hardware. The processing circuit 93 shown in FIG. 8 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The thing is applicable. As for the processing circuit, a part may be realized by dedicated hardware and a part may be realized by software or firmware. As described above, the processing circuit can realize each of the above-mentioned functions by the dedicated hardware, software, firmware, or a combination thereof.

The configuration shown in the above embodiments is an example, and can be combined with another known technique, can be combined with each other, and does not deviate from the gist. It is also possible to omit or change a part of the configuration.

For example, in a wireless communication system that does not use an error correction code, the error correction unit 109 of the receiving devices 100, 200, and 300 may be omitted. In an environment where the phase noise is so large that it cannot be ignored, a phase compensation function is provided in front of the frequency estimation unit 107 to follow the fluctuation of the phase offset of the received signal and observe the reference at the filter output or filter input. A process for correcting the amount of deviation from the phase may be added. Further, a waveform shaping filter having a fixed coefficient such as a roll-off filter may be provided after the RF circuit unit 102.

100, 200, 300 receiving device, 101 receiving antenna, 102 RF circuit unit, 103 timing control unit, 104 frequency control unit, 105, 205, 305 equalization processing unit, 106 timing estimation unit, 107 frequency estimation unit, 108 demapping Part, 109 error correction part, 110 reference signal generation part, 111 signal information identification part, 112,312 first equalization filter part, 113,313 second equalization filter part, 114,314 filter coefficient setting part, 115,215 , 315 filter coefficient synthesis unit, 116,316 filter switch control unit, 117 switch, 118 adder, 119 synthesis coefficient determination unit, 120 coefficient selector unit, 201 third equalization filter unit, 301 buffer unit, 302 selection composition unit.

Claims (12)

A receiving device in a wireless communication system in which the distortion characteristics of a received signal change with time.
An equalization processing unit that performs equalization processing of received signals,
A demapping unit that demaps the received signal after equalization processing acquired from the equalization processing unit, and a demapping unit.
Based on the demapping process result acquired from the demapping unit, the signal information identification unit that identifies the information indicating the distortion state of the received signal and generates the signal identification information.
Equipped with
The equalization processing unit is
With multiple equalization filters connected in parallel,
A filter switch control unit that switches whether or not to combine filter outputs from the plurality of equalization filter units based on the signal identification information.
A filter coefficient synthesizing unit that synthesizes the filter coefficients of the plurality of equalization filter units based on the signal identification information, and a filter coefficient synthesizing unit.
A receiving device characterized by comprising. The plurality of equalization filter units are
The first equalization filter unit for equalizing the linear distortion of the received signal, and
A second equalization filter unit for equalizing the non-linear distortion of the received signal,
The receiving device according to claim 1, wherein the receiving device comprises. A third equalization filter unit that generates a received signal after equalization processing for at least one of timing estimation and frequency estimation while keeping the filter coefficient fixed.
Equipped with
The filter coefficient synthesizing unit reads and synthesizes the filter coefficient set in the first equalization filter unit and the filter coefficient set in the second equalization filter unit, and combines them into the third equalization filter unit. Generate a filter coefficient to be set and set it in the third equalization filter unit.
2. The receiving device according to claim 2. The plurality of equalization filter units are filters of memory polynomials using a vortera filter.
The receiving device according to claim 1. The signal identification information includes the modulation method of the received signal, the coding rate of the received signal, the peak-to-average power ratio of the received signal, the amplifier operation backoff of the transmitting device which is the source of the received signal, and the reception. It comprises at least one of a signal-to-noise ratio of a signal, location information of the transmitter, and location information of the receiver.
The receiving device according to any one of claims 1 to 4, wherein the receiving device is characterized by the above. In the filter coefficient synthesizing unit, from the state in which the equalization processing unit sets the filter coefficients in the plurality of equalization filter units and performs the equalization processing, the filter switch control unit controls at least one equalization filter. When the filter output is turned off, the filter coefficients set in the plurality of equalization filter units are combined, and the equalization filter coefficients are newly set in the plurality of equalization filter units.
The receiving device according to any one of claims 1 to 5, wherein the receiving device is characterized by the above. When the filter coefficient synthesizing unit recognizes that the modulation method of the received signal has been switched from the non-constant envelope signal to the constant envelope signal based on the signal identification information, the filter coefficient synthesizing unit is set in the plurality of equalization filter units. Synthesize the existing filter coefficients,
The receiving device according to claim 6. In the filter coefficient synthesizing unit, from a state in which the equalization processing unit sets a filter coefficient in at least one equalization filter unit and performs equalization processing, the filter switch control unit controls another equalization filter unit. When the filter output changes from off to on, the filter coefficient of the equalization filter section where the filter output changes to on is set to a predetermined value.
The receiving device according to any one of claims 1 to 7, wherein the receiving device is characterized by the above. When the wireless communication system is a system in which a burst signal that is discontinuous in time arrives,
The equalization processing unit further
A buffer unit that stores received signals and controls the read address to perform equalization for channel estimation and demodulation equalization using tentative judgment values in a time-division manner.
The receiving device according to any one of claims 1 to 8, further comprising. A control circuit that controls a receiving device in a wireless communication system in which the distortion characteristics of a received signal change with time.
Equalization processing of received signal,
Demapping the received signal after equalization processing,
Based on the demapping process result, the information indicating the distortion state of the received signal is identified, and the signal identification information is generated.
To the receiving device
In the process of equalizing the received signal,
Based on the signal identification information, it is switched whether or not to combine the filter outputs from a plurality of equalization filter units connected in parallel.
Based on the signal identification information, the filter coefficients of the plurality of equalization filter units are combined.
A control circuit characterized by having a receiving device carry out the above. A storage medium that stores a program that controls a receiving device in a wireless communication system in which the distortion characteristics of a received signal change with time.
The program
Equalization processing of received signal,
Demapping the received signal after equalization processing,
Based on the demapping process result, the information indicating the distortion state of the received signal is identified, and the signal identification information is generated.
To the receiving device
In the process of equalizing the received signal,
Based on the signal identification information, it is switched whether or not to combine the filter outputs from a plurality of equalization filter units connected in parallel.
Based on the signal identification information, the filter coefficients of the plurality of equalization filter units are combined.
A storage medium, characterized in that the receiving device performs the above. It is a received signal processing method of a receiving device in a wireless communication system in which the distortion characteristic of the received signal changes with time.
An equalization processing step in which the equalization processing unit performs equalization processing of the received signal, and
A demapping step in which the demapping unit demapping the received signal after the equalization processing acquired from the equalization processing unit, and
A signal information identification step in which the signal information identification unit identifies information indicating a distortion state of the received signal based on the demapping processing result acquired from the demapping unit and generates signal identification information.
Including
The equalization processing step is
A control step in which the filter switch control unit switches whether or not to combine filter outputs from a plurality of equalization filter units based on the signal identification information.
A synthesis step in which the filter coefficient synthesizing unit synthesizes the filter coefficients of the plurality of equalization filter units based on the signal identification information.
A received signal processing method comprising.

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