Receiving device, receiving method and receiving system

Abstract

Receiving device which features: an equalization processor (20) comprising several time-of-flight equalizers (21, 22) which each receive several received signals through an array antenna (11, 12), and which performs equalization processing of spatial equalization and temporal equalization on the received signals, wherein the equalization processor (20) is configured as a: Gaining a first error (e1), which is a difference between an output of a specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and a given reference value (Target), and calculating a first weight (W1) with which the first error (e1) is minimized; Causing a calculation result of the first weighting (W1) to be reflected in all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) except for the specific tap (TAP_p), gaining a second error (e2) which is a difference between outputs of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) and the specified reference value (target), and calculating a second weighting (W2) with which the second error (e2) is minimized; and Updating coefficients of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) at the same time using the calculation result of the first weighting (W1) and a calculation result of the second weighting (W2) and calculating an output of the equalization processor (20).

Description

[0001] The present disclosure relates to a receiving device, a receiving method and a receiving system that receives a radio signal such as an FM broadcast wave.

[0002] When a radio signal is received by a receiving device, multipath interference is one of the factors that can impair the signal quality of the received signal. Multipath interference occurs when signal waves arriving via multiple paths have time differences, causing these signal waves to interfere with each other. This interference leads to a decrease in the received electric field, an angle detection shift during demodulation due to a phase shift, and a deterioration of signal quality, such as the audio quality of the received signal. Here, multipath interference is described as occurring when FM radio is received by a receiving device on a moving object, such as an aircraft radio receiver.

[0003] One of the first methods used to improve the quality degradation of the received signal caused by interference from multipath propagation is, for example, a diversity reception technique. Diversity reception techniques often employ a phase diversity method (adaptive array antenna), in which two antennas are arranged in an array to reduce interference. Phase diversity is a mechanism for removing interference by exploiting the fact that received waves arriving at two antennas have a phase difference (path difference) depending on their distance from the antennas. A method for removing interference through phase diversity can also be referred to as spatial equalization.Spatial equalization in FM reception generally employs a constant modulus algorithm (CMA) technique, utilizing the constant envelope characteristics of an FM signal to achieve an adaptive capability that mimics the propagation state of a radio signal. In an FM signal, audio information is superimposed by varying a carrier frequency over time, and there is no variation in the amplitude of the carrier wave. The CMA utilizes a constant amplitude characteristic of the FM signal, and a feedback control adjusts the weighting of the amplitude and phase so that any temporal variation in the signal amplitude at a receiving point becomes zero. This weighting is driven toward a target value to implement adaptive processing.

[0004] A second means of improving the quality degradation of the received signal caused by interference from multipath propagation is, for example, a time-of-flight equalizer. This equalizer estimates the propagation state of a radio signal from the state of a received wave and corrects an inverse state (inverse characteristic) of the propagation state by means of a delay tap. A method for removing interference using the time-of-flight equalizer can also be referred to as time-domain equalization. The adaptive processing in the time-of-flight equalizer is implemented, as with phase diversity, through feedback control using the CMA (Continuously Variable Array).

[0005] Furthermore, a third means of improving the quality degradation of the received signal caused by interference from multipath propagation is a multi-tap phase diversity method, which combines the phase diversity and the time-delay equalizer described above. Patent literature 1 discloses, as an example of the multi-tap phase diversity method, a decision-feedback equalizer that forms a spatiotemporal equalization system, combining spatial equalization based on an adaptive array antenna with temporal equalization based on a tapped delay line (TDL) filter. In the multi-tap phase diversity method, the adaptive processing is also implemented by feedback control using the CMA, as in the phase diversity or time-delay equalizer. Patent literature Patentliteratur 1: JP 2 663 820 B2 Patentliteratur 2: US 2004 / 0 190 649 A1 Patentliteratur 3: US 5 119 401 A Patentliteratur 4: JP H07 - 86 972 A

[0006] In the multi-tap phase diversity method of the related technique described above, a problem arises because adaptive processing is performed by treating the weighting of spatial and temporal equalization equally in an update rule. This makes achieving a spatial equalization effect difficult, and ideal equalization processing is not easily implemented. Attempting to make a correction value approximate an optimal solution in the spatiotemporal equalization system requires complex calculations, a large computational circuit, and significant processing time. Therefore, it is difficult to provide a usable receiving device, especially if the receiving device is used on a moving object such as an aircraft radio receiver.

[0007] The present disclosure was proposed in the related technology in view of the circumstances described above, and one objective of it is to provide a receiving device, a receiving method and a receiving system capable of performing more suitable equalization processing in a multiple-tap phase diversity method combining spatial equalization and temporal equalization.

[0008] The present disclosure provides a receiving device comprising: an equalization processor comprising several time-of-flight equalizers, each receiving several received signals through an array antenna, and performing equalization processing of spatial equalization and temporal equalization on the received signals, wherein the equalization processor is configured to: gain a first error, which is a difference between an output of a specific tap in the several time-of-flight equalizers and a predetermined reference value, and calculate a first weighting with which the first error is minimized;To cause a calculation result of the first weighting to be reflected in all taps in the multiple runtime equalizers except the specific tap, to gain a second error, which is a difference between the outputs of all taps in the multiple runtime equalizers and the specified reference value, and to calculate a second weighting with which the second error is minimized; and to update coefficients of all taps in the multiple runtime equalizers simultaneously using the calculation result of the first weighting and a calculation result of the second weighting, and to calculate an output of the equalization processor.

[0009] The present disclosure provides a receiving system comprising: a receiving signal input device that inputs a received signal of a radio wave; an equalization processor that performs equalization processing of the received signal; and an audio signal output device that outputs an equalized signal, wherein the receiving signal input device comprises: an array antenna comprising multiple antennas that receive radio waves of a desired wave; and front ends configured to each perform a frequency conversion of the multiple received signals, wherein the audio signal output device comprises: an output signal amplifier that amplifies an equalized signal;and an audio output device that outputs the amplified signal as an audio signal, wherein the equalization processor includes several time-delay equalizers, each of which receives several received signals, and performs spatial and temporal equalization processing on the received signals, wherein the equalization processor is configured to: gain a first error, which is a difference between an output of a specific tap in the several time-delay equalizers and a predetermined reference value, calculate a first weighting with which the first error is minimized;To cause a calculation result of the first weighting to be reflected in all taps in the multiple runtime equalizers except for the specific tap; to gain a second error, which is a difference between the outputs of all taps in the multiple runtime equalizers and the specified reference value; and to calculate a second weighting with which the second error is minimized; to update coefficients of all taps in the multiple runtime equalizers simultaneously using the calculation result of the first weighting and a calculation result of the second weighting; and to calculate an output of the equalization processor.

[0010] The present disclosure provides a reception method to be carried out in a receiving device, wherein the receiving device comprises: an equalization processor comprising several time-of-flight equalizers, each receiving several received signals through an array antenna, and performing equalization processing of spatial equalization and temporal equalization on the received signals, and the reception method comprises: gaining a first error, which is a difference between an output of a specific tap in the several time-of-flight equalizers and a predetermined reference value, in the equalization processor, calculating a first weighting with which the first error is minimized;To cause a calculation result of the first weighting to be reflected in all taps in the multiple runtime equalizers except for the specific tap; to gain a second error, which is a difference between the outputs of all taps in the multiple runtime equalizers and the specified reference value; to calculate a second weighting with which the second error is minimized; to update coefficients of all taps in the multiple runtime equalizers simultaneously using the calculation result of the first weighting and a calculation result of the second weighting; and to calculate an output of the equalization processor. Advantageous effects of the invention

[0011] According to the present disclosure, it is possible to perform a more suitable equalization processing in the multiple-tap phase diversity method, in which spatial equalization and temporal equalization are combined. Brief description of the drawings Fig. Figure 1 is a block diagram illustrating a design of a receiving device and a receiving system according to one embodiment. Fig. Figure 2 is a flowchart that represents a sequence of equalization processing of the receiving device according to the embodiment. Fig. Figure 3 is a diagram that illustrates an example of a relationship between a weighting and an error when spatial rectification is performed in the rectification processing according to the embodiment. Fig. Figure 4 is a diagram that illustrates an example of a relationship between a weighting and an error when temporal equalization is performed in the equalization processing according to the embodiment. Fig. 5A and Fig. 5B illustrates a situation where multipath propagation occurs, where Fig. 5A represents a picture of a plurality of propagation paths of a radio signal at the time of the occurrence of multipath propagation and Fig. 5B represents the arrival times of the respective receiving waves. Fig. Figure 6 presents, as a comparative example, a design example for a general multiple-tap phase diversity receiving device. Fig. Figure 7 is a diagram that illustrates an example of a relationship between a weighting and an error when equalization processing is performed by a multiple-sampling phase diversity procedure of the comparison example. Description of embodiments

[0012] In the following, embodiments that specifically describe a receiving device, a receiving method, and a receiving system according to the present disclosure are described in detail, optionally with reference to the accompanying drawings. However, detailed descriptions that go beyond what is necessary may be omitted. For example, detailed descriptions of a previously generally known subject matter, as well as redundant descriptions of components that are essentially the same, are omitted in some cases. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by a person skilled in the art. The accompanying drawings and the following descriptions are provided to help a person skilled in the art to fully understand the present disclosure and are therefore not intended to limit the subject matter described in the claims. (How the content of the present embodiment is obtained)

[0013] This section describes a specific example of a problem encountered using the multiple-tap phase diversity method. It outlines a situation where multipath propagation occurs when receiving a radio signal, such as FM broadcasting, and provides an example of equalization processing using the multiple-tap phase diversity method.

[0014] Fig. 5A and Fig. 5B are diagrams illustrating a situation where multipath propagation occurs, where Fig. 5A represents a picture of a plurality of propagation paths of a radio signal at the time of the occurrence of multipath propagation and Fig. 5B represents the arrival times of the respective received waves. For example, a radio wave transmitted by a broadcasting station's transmitting antenna propagates to a receiving antenna of a receiving device via multiple propagation paths, multiple received waves such as a desired wave S1, which propagates directly; a main interference wave S2 caused by multipath propagation, which is reflected by mountains or buildings; and other interference waves S3 caused by multipath propagation, which are reflected multiple times in a densely populated area or the like. In this case, the main interference wave S2 and other interference waves S3 are delayed in their arrival at the receiving antenna with respect to the desired wave S1.

[0015] Fig. Figure 6 presents, as a comparative example, a design example for a general multi-tap phase diversity receiving device. When equalization processing of a received signal is performed using the multi-tap phase diversity method in a multipath environment, as described above, spatial equalization and temporal equalization weights are calculated by an update rule using time-delay equalizers 121, 122 based on several sets of TDL filters (two sets in the illustrated example) to perform adaptive processing. To suppress the interference waves S2 and S3, an error e between an output y of the time-delay equalizers 121, 122 and a reference value Target is calculated, and a weight W of each tap to minimize the error e is calculated using the CMA by a weighting calculator 131.Subsequently, feedback control is performed by applying the weight W to a phase shifter of each tap of the propagation delay equalizers 121 and 122, and the output y approaches an optimal value. For example, if the two propagation delay equalizers 121 and 122 are each formed by a TDL filter with 16 taps, it is difficult for the weight to approach an optimal solution because the weight is calculated using a total of 32 variables, which is a complex calculation.

[0016] Fig. Figure 7 is a schematic representation that illustrates an example of the relationship between weighting and error when equalization processing is performed using the multiple-sampling phase diversity method of the [reference to relevant worksheet]. Fig. The comparative example shown in section 6 is carried out. If the error e with regard to the weighting W, as in Fig. Figure 7, depicted two-dimensionally, assumes that the initial state of the weight W is a value within a white circle, and that the equalization processing is initiated from a starting point within the white circle. In this case, the equalization processing should aim for a value within a star marker that minimizes the error e, i.e., an arrival point of the optimal value. However, the processing actually stops at a value within a white triangle, i.e., at an arrival point of the comparison example. This is because, during the equalization processing of the comparison example, a corresponding weight correction value is considered satisfied at a value (minimum solution) that is close to a minimum value from the starting point, thus terminating the processing.In the equalization processing of the comparison example, approximating the arrival point of the optimal value requires a complex calculation, a large computing circuit, and significant processing time. For example, in a receiving device for a moving object, such as an onboard radio receiver, where a design capable of high-speed processing with the simplest possible calculation is desired, this is not realistic from the perspective of the computational scope and the time-traceability of adaptive processing. Therefore, a problem arises: noise caused by interference waves resulting from multipath propagation cannot be suppressed, and noise is introduced into the received signal.

[0017] Therefore, the present embodiment represents a design example for a receiving device, a receiving method and a receiving system in which, in the multiple-tap phase diversity method, a result of adaptive processing can approximate an optimal value and more suitable equalization processing can be carried out.

[0018] In the present embodiment, examples of the receiving device, the receiving method and the receiving system according to the present disclosure include, for example, a design example applicable to an FM radio receiver mounted in a vehicle. (Design of the present embodiment)

[0019] Fig. Figure 1 is a block diagram illustrating a design of the receiving device and receiving system according to the embodiment. The receiving device of the present embodiment includes an equalization processor 20, which incorporates several time-delay equalizers (two time-delay equalizers in the illustrated example) that performs equalization processing of radio signals such as FM broadcast signals. The receiving system of the present embodiment includes, as a receiving signal input device, several antennas 11, 12 (two antennas in the illustrated example), front ends (FE) 13, 14, analog-to-digital converters (ADCs) 15, 16, and bandpass filters 17, 18. The receiving system may include a normalization processor 19 and a demodulator 33.Furthermore, the receiving system includes a digital-to-analog converter (DAC) 34, an amplifier 35 and a loudspeaker 36 as an audio signal output device.

[0020] Antennas 11 and 12 are arranged, for example, at intervals of half a wavelength of a desired wave frequency and form an array antenna that receives radio signals such as FM broadcasts through the two receiver units. Front-ends 13 and 14 perform frequency conversion and similar operations on the received signals in the RF (radio frequency) band received by antennas 11 and 12. Analog-to-digital converters 15 and 16 convert the received signals output by front-ends 13 and 14 from analog signals into digital signals. Bandpass filters 17 and 18 allow received signals to pass through in a predefined frequency band containing the frequency of the desired wave and block signals in other bands. The normalization processor 19 performs normalization processing to align the signal levels of the two received signals.The receive signal input device can be designed by means of an input interface or the like for inputting a receive signal of a radio wave of a desired wave from the array antenna.

[0021] The demodulator 33 includes an FM demodulator that demodulates an FM signal from a received signal and performs FM demodulation, such as stereo demodulation of left and right audio signals. The D / A converter 34 converts a demodulated signal of the digital signal output by the demodulator 33 into an analog signal. The amplifier 35 is an example of an output signal amplifier and includes an amplifier that amplifies an audio signal obtained by converting the demodulated signal into the analog signal. The loudspeaker 36 is an example of an audio output device; it reproduces and outputs an audio signal and plays back sound, such as FM radio broadcasts. The audio output device is not limited to the loudspeaker 36, and various devices such as headphones, earphones, and headsets can be used.The audio signal output device can be designed by means of an output interface or the like for outputting an audio signal of a demodulated signal.

[0022] The equalization processor 20 includes two time-delay equalizers 21, 22, a first combination unit 23, a first adder unit 24, a reference output unit 25, a second combination unit 26, a second adder unit 27, a first weighting calculator 31, and a second weighting calculator 32. The equalization processor 20 performs adaptive processing by means of feedback control using the CMA. Each of the time-delay equalizers 21, 22 is a time-delay equalizer based on a TDL filter and a time-delay equalizer of a plurality of taps (in this case, N taps). Here, the first time-delay equalizer 21 is referred to as the main TDL, and the second time-delay equalizer 22 is referred to as the secondary TDL. Each of the runtime equalizers 21, 22 includes N-1 delay elements 211, 221 of delay times T and N complex multiplication devices 212, 222.An array antenna consisting of three or more antennas can be provided in the receive signal input device, and the equalization processor can include three or more time-delay equalizers corresponding to the array antenna.

[0023] The first combination unit 23 combines the outputs of the two complex multiplier units 212 and 222 into a specific tap. The reference output unit 25 outputs a predefined reference value Target. The first adder unit 24 calculates the difference between the output of the first combination unit 23 and the reference value Target by subtracting the reference value Target of the output of the reference output unit 25 from the output of the first combination unit 23 and calculates an error e1 as a first error. The first weighting calculator 31 calculates a weight W1 as a first weight, which minimizes the error e1 using the CMA. The weight W1 is used as a weight for spatial equalization.

[0024] The second combination unit 26 combines the outputs of the two complex multiplier units 212 and 222 at all of the N taps. The second adder unit 27 calculates a difference between the output of the second combination unit 26 and the reference value Target by subtracting the reference value Target of the output of the reference value output unit 25 from the output of the second combination unit 26 and calculates an error e2 as a second error. The second weighting calculator 32 calculates a weight W2 as a second weight, which minimizes the error e2 using the CMA. The weight W2 is used as a weight for time equalization.

[0025] For example, a calculation of the weights W1 and W2 is performed using a Least Mean Square (LMS) algorithm to calculate update amounts of the weights W1, W2, which set the errors e1, e2 to zero.

[0026] In the present embodiment, the propagation delay equalizers 21, 22 simultaneously perform spatial equalization based on phase diversity and temporal equalization based on the respective primary and secondary TDLs, in the order from spatial equalization to temporal equalization. Specifically, in a spatiotemporal equalization system, the weight W1 of a tap is updated to perform the spatial equalization, and the amount of the update is passed on as a rotation vector to the complex multiplication devices 212, 222 by multiplying the weights W2 of other taps. Subsequently, the weights W2 are updated by the temporal equalization. The updating of the weights W1 and W2 by the spatial and temporal equalization is implemented by a single coefficient update. (Process of the present embodiment)

[0027] Fig. Figure 2 is a flowchart illustrating the equalization processing sequence of the receiving device according to the embodiment. In the following, each tap of the time-delay equalizer is also referred to as a TAP.

[0028] First, in the runtime equalizers 21, 22, a specific TAP_p is specified for performing spatial equalization in the N TAPs (TAP_1 to TAP_n) (step S11). The number p of the TAP is expressed by the following formula (1). 1≤P≤N

[0029] In the example of Fig. A TAP surrounded by a dashed line corresponds to the TAP for spatial equalization. For example, a first TAP_1 (p = 1) is specified for performing the spatial equalization. The TAP for performing the spatial equalization can optionally be freely specified, for example, p = N / 2 (TAP in the middle). Hereinafter, the TAP for performing the spatial equalization will also be referred to as the TAP for spatial equalization. Fig. In the following, all N TAPs surrounded by a dashed line correspond to a TAP for temporal equalization. The TAP used to perform temporal equalization will henceforth also be referred to as the TAP for temporal equalization.

[0030] Next, in the runtime equalizers 21, 22, the first combination unit 23, and the first adding unit 24, the error e1 of a single TAP (TAP_p) for spatial equalization is calculated (step S12). As shown in the following formula (2), a product of a tap coefficient W is used in the TAP_p. main of the main TDL and an input value x main and a product of a tap coefficient W sub of the secondary TDL and an input value x sup The first combination device 23 adds the combined value, the combined value is subtracted from the reference value Target by the first adding device 24, and in this way the error e1 is calculated. [Math. 1] e1=Target−|Wmainpn⋅xmainpn+W'subpn⋅xsubpn|

[0031] Next, using the calculated error e1, the weight W1 is calculated in the first weighting calculator 31, and a coefficient of the TAP for spatial equalization (TAP_p) is updated (step S13). The weight of TAP_p is set to Wp. n+1 updated as shown in the following formula (3). [Math. 2] Wpn⇒Wpn+1

[0032] Subsequently, in the spatial equalization TAP for the propagation time equalizers 21, 22, an update amount r of the spatial equalization TAP is calculated (step S14). The update amount r corresponds to a fluctuation range in phase and amplitude of the spatial equalization TAP and is obtained using the following formula (4). In formula (4), a superscript represents a complex conjugate number. [Math. 3] r=Wpn+1⋅Wpn¯|Wpn|2

[0033] Next, in the other TAPs for temporal equalization, besides the TAP for spatial equalization, the runtime equalizers 21 and 22 receive an update amount r of the TAP for spatial equalization to reflect (pass on) an update amount (step S15). A weight of TAP_k is applied to r·Wk n updated as shown in the following formula (5). Here, k of TAP_k is set to 1 to N, with the exception of p, in order to pass the update amount r of the spatial correction TAP to other temporal correction TAPs. [Math. 4] W'kn⇒r⋅Wkn (k = 1, ..., N except for p)

[0034] Next, in the runtime equalizers 21, 22, the second combination unit 26 and the second adding unit 27, the error e2 is corrected in a state where all TAPs of the TAPs are used for time equalization, based on updated weights Wk n the respective TAPs are calculated (step S16). As shown in the following formula (6), in the TAP_k (K = 1 to N) a product of a tap coefficient W is calculated. main of the main TDL after propagation of a spatial equalization and an input value x main and a product of a sampling coefficient W' sup of the secondary TDL after propagation of a spatial equalization and an input value x sup The values ​​are added and accumulated by the second combination device 26, the combined value is subtracted from the reference value Target by the second adding device 27, and in this way the error e2 is calculated. [Math. 5] e2=Target−∑k=1N|W'mainkn⋅xmainkn+W'subkn⋅xsubkn|

[0035] Next, using the calculated error e2, the weight W2 is calculated by the second weighting calculator 32, and the coefficients of TAP_1 to TAP_N (except for p) for spatial equalization are updated (step S17). The weight of TAP_k (k = 1 to N (except for p)) is set to Wk n+1 updated as shown in the following formula (7). [Math. 6] WKN⇒WKN+1 (k = 1, ..., N, except for p)

[0036] Subsequently, runtime equalizers 21 and 22 determine the output y by applying inputs x of the TAPs through all of the respective updated TAP coefficients Wk. n+1 (Step S18). As shown in the following formula (8), in the TAP_k (K = 1 to N) a product of the updated sampling coefficient W is used. main of the main TDL and an input value x mainand a product of an updated sampling coefficient W' sub of the secondary TDL and an input value x sup The output y is added and accumulated by the second combination device 26. [Math. 7] y=∑k=1N|W'mainkn+1⋅xmainkn+W'subkn+1⋅xsubkn|

[0037] The rectification processing in steps S11 to S18 is repeated in a predetermined time unit (frame), and the rectification processing is performed sequentially for each frame.

[0038] The above equalization processing performs the spatial equalization, carried out in a specific tap, and the temporal equalization, carried out in all taps, by reflecting the result of the spatial equalization and passing it on to all other taps, at the same coefficient update time. Accordingly, it is possible to provide a spatiotemporal equalization system capable of appropriately combining spatial and temporal equalization and allowing the weighting to approximate an optimal solution.

[0039] Fig. Figure 3 is a schematic representation showing an example of a relationship between a weighting and an error when spatial rectification is performed during rectification processing according to the embodiment, and Fig. Figure 4 is a schematic representation showing an example of a relationship between a weighting and an error when temporal equalization is performed in the equalization processing according to the embodiment.

[0040] Here, as in Fig. 3 and Fig. As shown in Figure 4, it is assumed that the error e1 with respect to weight W1 based on spatial equalization and the error e2 with respect to weight W2 based on temporal equalization are each represented two-dimensionally. In this case, it is assumed that the initial states of weights W1 and W2 are values ​​in white circles and that the equalization processing is initiated from the starting point in the white circle.

[0041] In this case, the error e1, viewed from the perspective of weighting W1, is based on spatial rectification, as in Fig. Figure 3 illustrates this, and the equalization processing control can approximate a value in a star marker that minimizes the error e1, that is, an arrival point of the optimal value. Accordingly, for example, in a situation where multipath propagation occurs, as in Fig. 5A and Fig. Figure 5B illustrates that the equalization processing can be performed by focusing on the main interference wave S2 caused by multipath propagation, which has a large interference effect due to spatial equalization, thus effectively suppressing the interference wave S2. The spatial equalization according to the present embodiment can be performed by a simple calculation of a tap, and the error e1 can be easily approximated to the arrival point of the optimal value.

[0042] The error e2, considered from the weighting W2 based on the temporal equalization, is, as in Fig. 4 is shown, and in the present embodiment, the update amount of the weight W1 based on the spatial equalization is passed to all taps of the temporal equalization, thus preventing the control of the equalization processing from terminating at a point close to a minimum value from the starting point. Therefore, the fine-tuning of the equalization processing based on the temporal equalization can continue, and the control of the equalization processing can approach the arrival point of the optimal value that minimizes the error e2. Therefore, for example, in a situation where multipath propagation occurs, as in Fig. 5A and Fig.Figure 5B shows that equalization processing can be carried out on a disturbance including other interference waves S3 caused by multipath propagation with a low interference effect through temporal equalization, and noise of the received signal can be reduced.

[0043] As described above, in the present embodiment, the result of the spatial equalization of one tap is reflected in the temporal equalization, and the weights are updated simultaneously. This ensures that the spatial and temporal equalization are performed appropriately without interfering with each other. Accordingly, disturbances in the received signal can be effectively eliminated, for example, in an environment where multipath propagation occurs during FM broadcast reception. Therefore, according to the present embodiment, the control can approximate an ideal error arrival point that is not obtained through a general multi-tap phase diversity method, and a less noisy spatial-time equalization processing can be provided.

[0044] As described above, the receiving device according to the present embodiment includes the equalization processor 20, which comprises the multiple time-of-arrival equalizers 21, 22, each of which receives multiple received signals through the array antennas 11, 12, and which performs spatial and temporal equalization processing on the received signal. The equalization processor 20 calculates the first error e1, which is a difference between an output of a specific tap in the multiple time-of-arrival equalizers 21, 22 and the predetermined reference value Target, and calculates the first weight W1, with which the first error e1 is minimized.The equalization processor 20 ensures that the calculation result of the first weight W1 is reflected in all taps in the multiple runtime equalizers 21, 22, except for the specific tap. It then calculates the second error e2, which is the difference between the outputs of all taps in the multiple runtime equalizers 21, 22 and the specified reference value Target, and calculates the second weight W2, which minimizes the second error e2. Furthermore, the equalization processor 20 simultaneously updates the coefficients of all taps in the multiple runtime equalizers 21, 22 using the calculation results of the first weight W1 and the second weight W2, and calculates the output y of the equalization processor 20.

[0045] In the receiving device of the present embodiment, each of the multiple time-delay equalizers 21, 22 has N taps from TAP_1 to TAP_n. The equalization processor 20 specifies a specific tap TAP_p among the N taps as the tap for performing spatial equalization, calculates the first weight W1 based on the output of the tap TAP_p in the multiple time-delay equalizers 21, 22, and updates the coefficient of the tap TAP_p. In a state where the update amount of the tap TAP_p is reflected in the taps TAP_1 to TAP_n except for the tap TAP_p, the equalization processor 20 calculates the second weight W2 based on the outputs of the N taps TAP_1 to TAP_n and updates the coefficients of the taps TAP_1 to TAP_n except for the tap TAP_p.The equalization processor 20 updates the coefficient of tap TAP_p based on the first weight W1 and the coefficients of taps TAP_1 to TAP_n, with the exception of tap TAP_p, based on the second weight W2 at the same coefficient update time.

[0046] Therefore, in the multi-tap phase diversity method, which combines spatial and temporal equalization, a problem can be avoided: the control process might terminate at a point near the minimum value from the starting point of the equalization processing. The result of the adaptive processing can then approach the optimal value. This allows for more suitable equalization processing during adaptive control of spatial and temporal equalization, and the main interference wave with a large impact at the time of multipath propagation can be effectively suppressed. Consequently, it is possible to prevent a decrease in the received signal strength of a desired wave, such as FM radio, to obtain a received signal with less noise, and to prevent a degradation in the audio quality of the received signal.

[0047] The receiving system according to the present embodiment is a receiving system comprising the receiving signal input device, which inputs a received signal of a radio wave; the equalization processor 20, which performs equalization processing of the received signal; and an audio signal output device, which outputs an equalized signal. The receiving signal input device includes the array antenna, which has the multiple antennas 11, 12 that receive radio waves of a desired wave, and the front ends 13, 14, which each perform a frequency conversion of the multiple received signals. The audio signal output device includes the amplifier 35, which amplifies an equalized signal, and the loudspeaker 36, which outputs the amplified signal as an audio signal.The equalization processor 20 detects the first error e1, which is a difference between the output of a specific tap in the multiple runtime equalizers 21, 22 and a predefined reference value, and calculates the first weight W1, which minimizes the first error e1. The equalization processor 20 then reflects the result of the calculation of the first weight W1 in all taps in the multiple runtime equalizers 21, 22 except for the specific tap, detects the second error e2, which is a difference between the outputs of all taps in the multiple runtime equalizers 21, 22 and the predefined reference value, and calculates the second weight W2, which minimizes the second error e2.Furthermore, the equalization processor 20 updates the coefficients of all taps in the multiple runtime equalizers 21, 22 at the same time using the calculation results of the first weighting W1 and the second weighting W2 and calculates the output y of the equalization processor 20.

[0048] Therefore, it is possible to perform a more suitable equalization processing in the multiple-tap phase diversity method, which combines spatial equalization and temporal equalization.

[0049] Furthermore, the reception method according to the present embodiment is a reception method to be carried out in the receiving device, which includes the equalization processor 20, which has the multiple time-delay equalizers 21, 22, each of which receives multiple received signals through the array antennas 11, 12, and which performs spatial and temporal equalization processing on the received signal. The reception method includes: gaining the first error e1, which is a difference between an output of a specific tap in the multiple time-delay equalizers 21, 22 and a predetermined reference value, in the equalization processor 20;Calculating the first weight W1, which minimizes the first error e1, thereby ensuring that the calculation result of the first weight W1 is reflected in all taps in the multiple runtime equalizers 21, 22 except for the specific tap; calculating the second error e2, which is a difference between the outputs of all taps in the multiple runtime equalizers 21, 22 and the specified reference value; calculating the second weight W2, which minimizes the second error e2; updating the coefficients of all taps in the multiple runtime equalizers 21, 22 simultaneously using the calculation results of the first weight W1 and the second weight W2, and calculating the output y of the equalization processor 20.

[0050] Therefore, it is possible to perform a more suitable equalization processing in the multiple-tap phase diversity method, which combines spatial equalization and temporal equalization.

[0051] Although various embodiments have been described above with reference to the drawings, it is understood that the present disclosure is not limited to such examples. It is obvious that a person skilled in the art can imagine various modifications or corrections within the scope defined by the claims, and such modifications or corrections are to be considered as belonging to the technical scope of the present disclosure. Furthermore, the components according to the embodiments described above can be freely combined with one another without deviating from the scope of the present disclosure.

[0052] This application is based on Japanese patent application No. 2018-066239, filed on March 29, 2018, the contents of which are incorporated herein by reference. Commercial applicability

[0053] The present disclosure is usable as a receiving device, receiving method and receiving system which are capable of performing more suitable equalization processing in a multiple-tap phase diversity method in which spatial equalization and temporal equalization are combined. List of reference symbols 11, 12 Antenna 13, 14 Front-End 15, 16 A / D converters 17, 18 Bandpass filters 19 Normalization processor 20 equalization processor 21, 22 Runtime equalizer 23 first combination device 24 first adding device 25 Reference Value Output Device 26 second combination device 27 second adding device 31 first weighting calculator 32 second weighting calculator 33 Demodulator 34 D / A converters 35 amplifiers 36 speakers

Claims

[1] Receiving device comprising: an equalization processor (20) comprising several time-of-flight equalizers (21, 22) which each receive several received signals through an array antenna (11, 12), and which performs equalization processing of spatial equalization and temporal equalization on the received signals, wherein the equalization processor (20) is configured as a: Gaining a first error (e1), which is a difference between an output of a specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and a given reference value (Target), and calculating a first weight (W1) with which the first error (e1) is minimized; Causing a calculation result of the first weighting (W1) to be reflected in all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) except for the specific tap (TAP_p), gaining a second error (e2) which is a difference between outputs of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) and the specified reference value (target), and calculating a second weighting (W2) with which the second error (e2) is minimized; and Updating coefficients of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) at the same time using the calculation result of the first weighting (W1) and a calculation result of the second weighting (W2) and calculating an output of the equalization processor (20). [2] Receiving device according to claim 1, wherein each of the multiple runtime equalizers (21, 22) has N taps (TAP_1 to TAP_n) from a first tap (TAP_1) to an nth tap (TAP_n), and wherein the equalization processor (20) is configured as a: Specifying the specific tap (TAP_p) among the N taps (TAP_1 to TAP_n) as a tap for performing spatial equalization, calculating the first weight (W1) based on an output of the specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and updating a coefficient of the specific tap (TAP_p), in a state where an update amount of the specific tap (TAP_p) is reflected in the first tap (TAP_1) to the nth tap (TAP_n) except for the specific tap (TAP_p), calculating a second weight (W2) based on outputs of the N taps (TAP_1 to TAP_n) from the first tap (TAP_1) to the nth tap (TAP_n) and updating coefficients of the first tap (TAP_1) to the nth tap (TAP_n) except for the specific tap (TAP_p), and Updating the coefficient of the specific sampling (TAP_p) based on the first weighting (W1) and the coefficients of the first sampling (TAP_1) to nth sampling (TAP_n) except for the specific sampling (TAP_p) based on the second weighting (W2) at the same update time. [3] Receiving device according to claim 2, wherein each of the multiple propagation delay equalizers (21, 22) has N-1 delay elements (211, 221) and N complex multiplier devices (212, 222) of the first tap (TAP_1) to nth tap (TAP_n) which are connected to input sides and output sides of the N-1 delay elements (211, 221). [4] Receiving device according to claim 3, wherein the equalization processor (20) comprises: a first combination device (23) configured to combine outputs of the complex multiplication devices (212, 222) of the specific tap (TAP_p) of the multiple runtime equalizers (21, 22); a first adding device (24) which is configured to output as the first error (e1) a difference between an output of the first combination device (23) and the reference value (target); a first weighting calculator trained to calculate the first weight (W1) based on the first error (e1) output by the first adding device (24) and to update the first weight (W1) to update the coefficient of the specific tap (TAP_p). [5] Receiving system which features: a receiving signal input device (11, 12, 13, 14, 15, 16, 17, 18) that inputs a receiving signal from a radio wave; an equalization processor (20) that performs equalization processing of the received signal; and an audio signal output device (34, 35, 36) that outputs an equalized signal, wherein the receiving signal input device (11, 12, 13, 14, 15, 16, 17, 18) comprises: an array antenna (11, 12) comprising multiple antennas (11, 12) that receive radio waves of a desired wave; and Front-ends (13, 14) designed to each perform a frequency conversion of the multiple received signals, wherein the audio signal output device (34, 35, 36) comprises: an output signal amplifier (35) that amplifies an equalized signal; and a sound output device (36) which outputs the amplified signal as a sound signal, and wherein the equalization processor (20) has several time-delay equalizers (21, 22) which each receive several received signals, and performs equalization processing of the spatial equalization and the temporal equalization on the received signals, wherein the equalization processor (20) is configured as a: Gaining a first error (e1), which is a difference between an output of a specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and a given reference value (Target), and calculating a first weight (W1) with which the first error (e1) is minimized; Causing a calculation result of the first weighting (W1) to be reflected in all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) except for the specific tap (TAP_p), gaining a second error (e2) which is a difference between outputs of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) and the specified reference value (target), and calculating a second weighting (W2) with which the second error (e2) is minimized; and Updating coefficients of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) at the same time using the calculation result of the first weighting (W1) and a calculation result of the second weighting (W2) and calculating an output of the equalization processor (20). [6] Receiving system according to claim 5, wherein each of the multiple runtime equalizers (21, 22) has N taps (TAP_1 to TAP_n) from a first tap (TAP_1) to an nth tap (TAP_n), and wherein the equalization processor (20) is configured as a: Specifying the specific tap (TAP_p) among the N taps (TAP_1 to TAP_n) as a tap for performing spatial equalization, calculating the first weight (W1) based on an output of the specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and updating a coefficient of the specific tap (TAP_p), in a state where an update amount of the specific tap (TAP_p) is reflected in the first tap (TAP_1) to the nth tap, excluding the specific tap (TAP_p), calculating a second weight (W2) based on outputs of the N taps (TAP_1 to TAP_n) from the first tap (TAP_1) to the nth tap (TAP_n) and updating coefficients of the first tap (TAP_1) to the nth tap (TAP_n), excluding the specific tap (TAP_p), and Updating the coefficient of the specific tap (TAP_p) based on the first weight (W1) and the coefficients of the first tap (TAP_1) to nth tap (TAP_n) except for the specific tap (TAP_p) based on the second weight (W2) at the same time. [7] Receiving system according to claim 6, wherein each of the multiple propagation delay equalizers (21, 22) comprises N-1 delay elements (211, 221) and N complex multiplier devices (212, 222) of the first tap (TAP_1) to nth tap (TAP_n) which are connected to input sides and output sides of the N-1 delay elements (211, 221). [8] A reception method to be carried out in a receiving device, wherein the receiving device comprises: an equalization processor (20) comprising several time-of-flight equalizers (21, 22) each receiving several received signals through an array antenna (11, 12), and which performs equalization processing of spatial equalization and temporal equalization on the received signals, wherein the receiving method comprises: in the equalization processor (20), Recovering a first error (e1), which is a difference between the output of a specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and a predefined reference value (target), and calculating a first weight (W1) to minimize the first error (e1); causing the result of the first weight calculation (W1) to be reflected in all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) except for the specific tap (TAP_p); recovering a second error (e2), which is a difference between the outputs of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) and the predefined reference value (target), and calculating a second weight (W2) to minimize the second error (e2); and Updating coefficients of all taps (TAP_1 to TAP_n) in the multiple runtime equalizers (21, 22) at the same time using the calculation result of the first weighting (W1) and a calculation result of the second weighting (W2) and calculating an output of the equalization processor (20). [9] Receiving method according to claim 8, wherein each of the multiple runtime equalizers (21, 22) has N taps (TAP_1 to TAP_n) from a first tap (TAP_1) to an nth tap (TAP_n), and the receiving procedure exhibits: Specifying the specific tap (TAP_p) among the N taps (TAP_1 to TAP_n) as a tap to perform spatial equalization, calculating the first weight (W1) based on an output of the specific tap (TAP_p) in the multiple runtime equalizers (21, 22) and updating a coefficient of the specific tap (TAP_p); Causing an update amount of the specific tap (TAP_p) to be reflected in the first tap (TAP_1) to the nth tap (TAP_n) except for the specific tap (TAP_p), calculating a second weight (W2) based on outputs of the N taps (TAP_1 to TAP_n) from the first tap (TAP_1) to the nth tap (TAP_n) and updating the coefficients of the first tap (TAP_1) to the nth tap (TAP_n) except for the specific tap (TAP_p); and updating the coefficient of the specific tap (TAP_p) based on the first weight (W1) and the coefficients of the first tap (TAP_1) to nth tap (TAP_n) except for the specific tap (TAP_p) based on the second weight (W2) at the same time. [10] Receiving method according to claim 9, wherein the effect that the update amount of the specific tap (TAP_p) is reflected in the first tap (TAP_1) to nth tap (TAP_n) with the exception of the specific tap (TAP_p) comprises: Calculate the update amount of the specific tap (TAP_p) based on an initial weight (W1) before an update and an initial weight (W1) after an update; and Multiply the weights of the first tap (TAP_1) to the nth tap (TAP_n), excluding the specific tap (TAP_p), by the update amount of the specific tap (TAP_p).

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