WO2006085502A1

WO2006085502A1 - Diversity reception method and reception apparatus in wired communication

Info

Publication number: WO2006085502A1
Application number: PCT/JP2006/301969
Authority: WO
Inventors: Tadashi Araki; Minoru Okada
Original assignee: Sumitomo Electric Industries, Ltd.; National University Corporation NARA Institute of Science and Technology
Priority date: 2005-02-09
Filing date: 2006-02-06
Publication date: 2006-08-17
Also published as: JP2008141224A

Abstract

A current signal (ir(t)) and a voltage signal (vr(t)) of a pair of lines, such as power lines, intra-vehicle wirings and telephone lines, are detected at a reception end of the pair of lines. A combining/equalizing part (6) multiples a current signal (Ir(k)) and a voltage signal (Vr(k)), which are obtained by Fourier transforming, by weight coefficients (gi(k),gv(k)), respectively, and then adds the multiplication results together. The weight coefficients (gi(k),gv(k)) are decided such that the S/N ratio of a signal obtained by that addition is maximized. The complementary relationship between the current and the voltage can be utilized so as to improve the reception quality.

Description

Diversity receiving method and receiving apparatus in wired communication

Technical field

TECHNICAL FIELD [0001] The present invention relates to a diversity receiving method and a receiving apparatus that improve reception quality when communication is performed using a line such as a power line, a wiring in an automobile, and a telephone line as a transmission line. .

Background art

[0002] The diversity reception method is a method of improving reception quality by receiving a plurality of reception signals having the same content and combining them or selecting one having better quality.

Diversity reception methods have been conventionally used in the field of wireless communications, such as signals received on different antennas, signals with different polarizations, and signals with different arrival angles (diversity branch signals are called diversity branches), etc. On the other hand, it has been done to improve the quality of received signals.

[0003] The idea of diversity reception is also adopted in wired communication (see Patent Documents 1 and 2).

Patent Documents 1 and 2 propose a method for diversity reception of a communication signal at a receiving end via a plurality of power lines through which the same communication signal is transmitted.

Patent Document 1: JP 2004-64405 A

Patent Document 2: JP-A-11-205201

Patent Document 3: US Pat. No. 4,668,934 (Japanese Patent Laid-Open No. 61-101127) Disclosure of Invention

Problems to be solved by the invention

However, the diversity receiving methods described in Patent Documents 1 and 2 use a plurality of lines.

For this reason, it is necessary to lay a plurality of lines between the transmitting end and the receiving end, which causes a problem that the cost for constructing the communication system increases.

In general, in order to obtain the effect of improving the reception quality by diversity, the diversity branch The correlation between them needs to be small. That is, when one is in a bad state (eg, the amplitude is small), the other is bad (eg, the amplitude is large).

[0005] The present inventor has noted that the relationship between the current flowing through the pair of lines and the voltage is a complementary relationship.

That is, when the impedance of the load connected to the line is large, the load voltage increases and the current decreases. If the load impedance is small, the load voltage decreases and the current increases.

[0006] Therefore, since the current and the voltage have a complementary relationship at the signal receiving end, if these are selected as the diversity branch, an effect of improving the reception quality can be expected.

An object of the present invention is to provide a diversity receiving method and a receiving apparatus capable of improving reception quality using current and voltage that are in a complementary relationship at a signal receiving end in wired communication.

Means for solving the problem

In the diversity reception method of the present invention, when signals are communicated by being superimposed on a pair of lines, the voltage and current of the line are detected at the receiving end of the line, respectively, and the detected voltage signal, This is a method of diversity receiving a detected current signal.

This method can be expected to improve reception quality by using the complementary relationship between current and voltage.

[0008] The diversity reception method of the present invention is a method of communicating signals by superimposing signals on a pair of lines, respectively detecting the voltage and current of the line at the receiving end of the line, and detecting the detected current signal and In this method, each voltage signal is subjected to Fourier transform, and the current signal and voltage signal subjected to the Fourier transform are combined for each frequency component to receive diversity.

In this method, a current signal and a voltage signal are each Fourier-transformed and converted into a frequency domain signal, and then synthesized. In particular, when a broadband signal is transmitted, the frequency characteristics of the load impedance generally vary in a signal band that is not uniform.

FIG. 1 is a graph in which the horizontal axis represents frequency, and the vertical axis represents current signal and voltage signal amplitudes. . The frequency characteristics of the current signal and the voltage signal are not uniform, and the current signal and the voltage signal have opposite patterns. According to the method of the present invention, current signals and voltage signals that are complementary in the frequency domain can be combined to complement each other, and the nonuniformity of the signal spectrum within the band can be improved.

[0010] In the diversity reception, the voltage signal and the current signal may employ so-called combining diversity, in which the current signal and the voltage signal are combined with weighting so that the reception quality is optimal. Of these, so-called selection diversity, which selects the one with the better reception quality, may be employed. Selection diversity can be thought of as combining diversity where one of the weighting factors is 1 and the other is 0. An example of the reception quality is SNi: 匕.

[0011] In particular, if one of the voltage signal and the current signal is a real part and the other is an imaginary part to create a complex time signal and perform Fourier transform, the voltage signal and the current signal are individually Fourier transformed. Compared to the conversion, the number of Fourier transform circuits can be halved, and the circuit configuration of the Fourier transform circuit is simplified.

As a signal transmission system related to the Fourier transform, there are an OFDM system and a single carrier block transmission system.

[0012] The line is, for example, a power line, a wiring in a car, or a telephone line. When a power line or a wiring in an automobile is used as a track, the load impedance of the electrical device connected to the track varies with time depending on the power on / off of the device. Also, when the line is a telephone line, the load impedance varies depending on the on-hook and off-hook of the telephone connected to the line, so that the present invention can be effectively applied.

[0013] Further, the diversity receiver of the present invention receives signals superimposed on a pair of lines, detects a current signal obtained by detecting the current of the line, and a voltage of the line. A diversity receiving unit is provided for diversity receiving the obtained voltage signal.

This device can be expected to improve reception quality by using the complementary relationship between current and voltage.

[0014] Further, the diversity receiver of the present invention uses a current signal obtained by detecting the current of the line and a voltage signal obtained by detecting the voltage of the line as frequency signals, respectively. A Fourier transform unit that performs Fourier transform, and a diversity receiver that synthesizes the Fourier-transformed current signal and voltage signal for each frequency component are provided.

By performing the Fourier transform, it is possible to synthesize a current signal and a voltage signal that are complementary in the frequency domain, thereby improving the non-uniformity of the signal spectrum within the band.

[0015] The current signal can be obtained through a current detection unit that detects current at the receiving end of the line, and the voltage signal is obtained through a voltage detection unit that detects voltage at the receiving end of the line. be able to. According to this configuration, a current signal and a voltage signal can be obtained without installing a current detection unit and a voltage detection unit inside the reception device, and the reception device can be downsized.

The above-described or other advantages, features, and effects of the present invention will be made clear by the following description of embodiments with reference to the accompanying drawings.

Brief Description of Drawings

FIG. 1 is a graph showing frequency characteristics of amplitudes of a current signal and a voltage signal.

FIG. 2 is a block diagram showing a signal detection circuit at a power receiving end when signals are communicated with being superimposed on a pair of power lines or telephone lines.

FIG. 3 is a circuit block diagram when a high-pass filter F is used for each of the current component detection circuit and the voltage component detection circuit.

FIG. 4 is a diagram for explaining the principle of synthetic diversity.

FIG. 5 is a block diagram showing an OFDM combining diversity receiver.

FIG. 6 is a block diagram showing an SCBT system diversity receiver.

FIG. 7 is a block diagram showing a simplified synthesis diversity FFT circuit.

FIG. 8 is a block diagram showing a simplified combining diversity receiver of the OFDM system.

FIG. 9 is a block diagram showing an SCBT receiver.

Explanation of symbols

[0017] 1 Current component detection circuit

2 Voltage component detection circuit

3 Load

4a, 4b N-symbol serial-parallel converter 5, 5a, 5b FFT circuit

6 Synthesis equalization section

7 Demodulator

8a, 8b Channel characteristics estimation unit

9 IFFT circuit

10 N simponore parallel to serial converter

14a, 14b N symbol parallel to serial converter

51 Complexation part

52 FFT

53 Calculation unit

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram showing a signal detection circuit at a power receiving end of a power line or telephone line when communication is performed with signals superimposed on a pair of power lines or telephone lines.

The power line may be a transmission / distribution line that supplies commercial power to a home or office, or an in-vehicle wiring that supplies DC power in the vehicle.

[0019] The signal may be any of a baseband code signal such as an RZ code and a Manchester code, or a band signal subjected to digital modulation such as PSK, FSK, and QAM.

The signal is detected as a current signal by the current component detection circuit 1 and detected as a voltage signal by the voltage component detection circuit 2.

[0020] The current signal can be easily detected as, for example, a voltage across a resistor inserted in series with the line. However, since a loss occurs when the resistor is inserted, a coil (current transformer) surrounding the line may be inserted. It is common. Here, as a type of current transformer, a current probe is used that detects the voltage generated in the winding by inserting a power line into the magnetic circuit of the transformer.

The voltage signal can be detected by detecting the voltage generated between the lines at the receiving end, and the circuit configuration for the detection is arbitrary.

[0021] It should be noted that the current signal itself is not necessarily represented by a current change! It may be converted into a voltage by a resistor or the like. In the following description of the embodiment of the present invention, it is assumed that both the current signal and the voltage signal are signals represented by voltage changes.

In the diversity reception method of the present invention, these current signals and voltage signals are handled as diversity branches, and the reception quality is improved by combining these voltage signals and current signals or by selecting one of them.

[0022] The frequency band of the detected voltage signal and current signal is higher than the power line power frequency of the power line and the telephone signal frequency of the telephone line. It is desirable to pass through a high-pass filter F to eliminate it.

FIG. 3 is a circuit block diagram when the high-pass filter F is used for each of the current component detection circuit 1 and the voltage component detection circuit 2. The form of the high-pass filter F is arbitrary, such as a circuit using resistors and capacitors, or a circuit using coils and capacitors.

Hereinafter, these detected current signals are represented as ir (t), and voltage signals are represented as vr (t).

In the diversity method, “combined diversity” that adds a predetermined weighting factor to the current signal ir (t) and the voltage signal vr (t) for the best communication quality, and the current signal ir (t), There is “Selective Diversity” to select whichever of the voltage signal vr (t) is better or better communication quality. “Communication quality is good” means, for example, higher received power, higher signal-to-noise ratio, or lower transmission distortion. In addition, there is a type of selection diversity in which the selection switching circuit is installed in the pre-demodulation stage where the selection switching circuit is installed in the pre-demodulation stage.

[0024] In the following embodiment, a detailed explanation will be given by taking synthetic diversity as an example.

FIG. 4 is a diagram for explaining the principle of synthetic diversity.

The current signal ir (t) and voltage signal vr (t) are converted into frequency signals Ir (k) and Vr (k) by Fourier transform (FFT), respectively. In Fig. 4, the frequency spectrum of Ir (k) and the frequency spectrum of Vr (k) complement each other. Therefore, at a frequency where the amplitude of Ir (k) is large, Ir (k) is multiplied by a large weighting factor and Vr (k) is multiplied by a small weighting factor, and at a frequency where the amplitude of Vr (k) is large, Vr Multiply (k) by a large weighting factor and Ir (k) by a small weighting factor. By combining both signals, a combined signal as shown in Fig. 4 can be obtained. this Compared to Ir (k) alone or Vr (k) alone, the synthesized signal has a larger amplitude vector. In the case of the SCBT method, which will be described later, as shown in Fig. 4, the synthesized signal is inversely Fourier transformed and converted back to a time signal for demodulation. In the case of the OFDM method, the combined signal is demodulated for each frequency component.

[0025] Hereinafter, a specific example of the combined diversity receiver will be described in detail.

FIG. 5 is a block diagram showing an OFDM (Orthogonal Frequency Division Multiplex) scheme combining diversity receiver.

The combined diversity receiver inputs the current signal ir (t) and the voltage signal vr (t) to V, respectively. The current signal ir (t) is converted into 2N parallel signals through a serial-parallel conversion circuit 4a that parallelizes the serialized signal every N symbols (N is 256, for example). The voltage signal vr (t) also becomes 2N parallel signals through the N-symbol serial / parallel conversion circuit 4b. 〃2 "is added because the IFFT (Inverse Fourier Transform) circuit has complex input and output, so it has an imaginary part as well as a real part. However, the current signal ir (t) and voltage signal vr (t) are Since it is a real signal, the values of the imaginary part are all zero.

[0026] Each parallel signal is Fourier-transformed by FFT circuits 5a and 5b. The Fourier transformed signal is expressed as Ir (k), Vr (k). Here, “k〃” is a variable representing the discrete frequency, and k = 0, l, 2, ..., N-l.

On the other hand, the transmission path characteristics of the current signal ir (t) and the voltage signal vr (t) are estimated by the transmission path characteristics estimation units 8a and 8b, respectively. Transmission path characteristics are the transfer function from the transmission end to the reception end of the line. For example, it can be obtained by extracting a noise signal that is pre-inserted into the signal with a filter and measuring its intensity and phase.

[0027] The transmission path characteristic estimators 8a and 8b output the transfer function in the frequency domain for the current signal Ir (k) and the voltage signal Vr (k). These signals are a total of 2N parallel signals of the real part and imaginary part expressed by the same discrete frequency as the above discrete frequency k, and are expressed as hi (k) and hv (k), respectively. hi (k) and hv (k) represent transmission path characteristics.

The synthesis equalization unit 6 multiplies the signals Ir (k) and Vr (k) after the respective Fourier transforms by weighting factors gi (k) and gv (k) and adds them. The added signal R (k) is expressed as follows.

[0028] R (k) = gi (k) Ir (k) + gv (k) Vr (k) The power PS (k) and noise PN (k) of the added signal R (k) are

PS (k) = σ d ² | gi (k) hi (k) + gv (k) hv (k) | ²

PN (k) = 2 an ² (| gi (k) 卩 + | gv (k) | ² )

It is represented by Here, σ d ² is the power of the transmission signal, and 2 σ η ² is the power of noise added by the receiver. Since hi (k) and hv (k) have already been obtained in the channel characteristics estimation units 8a and 8b, under the constraint of gi (k) hi (k) + gv (k) hv (k) = l , SN ratio

PS (k) / PN (k) = σ d ² Ζ [2 σ n ² (| gi (k) | ² + | gv (k) | ² )]

In order to obtain a weighting coefficient that maximizes, weight coefficients gi (k) and gv (k) that minimize the denominator can be obtained.

[0029] Using Lagrange's undetermined coefficient method (Lagrange multiplier), the weighting coefficients gi (k) and gv (k) when the S / N ratio is maximized are calculated using hi (k) and hv (k). ,

gv (k) = hV (k) / (| h * i (k) I ² + | hV (k) | ² )

It is represented by Where 〃 * 〃 represents the complex conjugate.

The synthesis equalization unit 6 determines the weight coefficients gi (k) and gv (k) so as to maximize the SN ratio of the signal R (k) after the addition.

As a result, the error rate of the demodulated signal can be minimized.

Note that the transmission path characteristic estimation units 8a and 8b described above may use other powers that have determined hi (k) and hv (k) as transmission path characteristics using pilot signals. For example, a method of estimating the transmission path characteristics by inserting a signal having a shape-divided shape (such as a chirp signal or a PN sequence) at appropriate intervals and measuring the distortion at the receiver side, or transmitting data symbols Instead, there is a method of estimating the transmission path characteristics by transmitting known symbols at regular intervals and measuring the distortion.

[0031] Also, the synthesis equalization unit 6 determines the weighting factors gi (k) and gv (k) so that the signal-to-noise ratio of the signal R (k) is maximized. Other conditions that can be set may be set. For example, a condition that minimizes the BER (Bitzer rate) may be set.

The signal R (k) added by the synthesis equalization unit 6 enters the demodulator 7 and is converted into the original code string. The code string is parallel-serial converted by the N symbol parallel-serial conversion circuit 10 and extracted as information data. [0032] As described above, this combined diversity receiver detects a current signal and a voltage signal at the power receiving end of the power line or telephone line, and sends the current signal and the voltage signal to a predetermined value so that the transmission characteristics are the best. Since they are synthesized with weights, the best signal can be restored at any point in time.

Next, the case of the Ngnore-chirizo block izs transmission method (; single carrier block transmission, ¾ CBT, hereinafter referred to as SCBT method) will be described.

[0033] Note that the SCBT scheme is a block transmission scheme in which a signal block composed of a plurality of information symbols is transmitted and equalization and demodulation processing is performed in units of blocks on the receiving side! This is a transmission method in which a guard interval (GI) is added to a block and discrete frequency domain equalization is performed on the receiving side.

Here, the signal is a baseband signal for transmitting information symbols in a single frequency band, or a band signal obtained by modulating a single carrier.

[0034] As a guard interval, a copy of the last part of the transmission block (cyclic prefix) is inserted. This is called CP (single carrier block transmission witn cyclic prefix method), and discrete Fourier transform is used on the receiving side. (See “Frequency Domain Equalization for Single-Carrier Broadband Wireless Systems IEEE Communications Magazin April 2002, p.58-66.”)

[0035] FIG. 6 is a block diagram showing an SCBT combined diversity receiver in wired communication.

The difference between the SCBT method and the OFDM method is that in the OFDM method, the signal is subjected to inverse Fourier transform on the transmission side and sent to the transmission line, and the receiver performs Fourier transform and equalizes the signal for use. In the SCBT system, the transmitter sends the signal to the transmission line without performing the inverse Fourier transform, the receiver performs the Fourier transform, equalizes the signal in the frequency domain, and uses the inverse Fourier transform. From the viewpoint of the transmitted signal spectrum, OFDM is a multi-carrier and SCBT is a single carrier.

[0036] Since the reception time signal is subjected to discrete Fourier transform on the SCBT receiver side, the contents of the present invention described above can be applied. Therefore, SCBT N-symbol serial / parallel conversion circuits 4a and 4b, FFT circuit 5, transmission path characteristic estimation units 8a and 8b, and synthesis equalization unit 6 is substantially the same circuit as the OFDM system circuit.

In FIG. 6, the signal R (k) synthesized by the synthesis equalizer 6 is inverse Fourier transformed by the IFFT circuit 9 and transformed to a symbol string on the time axis. The symbol string is serially converted to N symbols, demodulated by a demodulator 7, and extracted as information data.

[0037] As described above, the SCBT scheme diversity receiver can restore the best signal at any point in time, similar to the OFDM scheme diversity receiver.

Next, a simplified synthesis diversity method in which one of the current signal ir (t) and the voltage signal vr (t) is regarded as a real part and the other one as an imaginary part will be described.

[0038] In the circuits shown in Figs. 5 and 6, the current signal ir (t) is represented by 2N parallel complex signals. N of the imaginary part is 0, and the real part is actually required. N. The voltage signal vr (t) is also represented by 2N parallel complex signals, of which N in the imaginary part are 0 and what is actually required is N in the real part. Therefore, the FFT circuits 5a and 5b have a redundant circuit configuration.

Fig. 7 shows this simplified synthesis diversity FFT circuit 5. This FFT circuit 5 is obtained by multiplying the real part of the current signal ir (t), which is N parallel signals, and the real part of the voltage signal vr (t), which is N parallel signals, by an imaginary unit j. Sum with

u (t) = ir (t) + jvr (t)

Is the input signal. The input signal u (t) is Fourier-transformed, and the frequency domain signal U (k) = X (k) + jZ (k) is obtained at the output of the FFT circuit 5. Here, X (k) and Z (k) are the real part and imaginary part of U (k), respectively. Since X (k) and Z (k) are not Fourier transform values of the desired current and voltage signals, they are converted to Fourier transform values Ir (k) and Vr (k) of the current and voltage signals by the following calculation. .

[0039] Ir (k) = [X (k) / 2 + X (N-k) / 2] + j [Z (k) / 2-Z (n-k) / 2] (1)

Vr (k) = [Z (k) / 2 + Z (N-k) / 2] j [X (k) / 2— X (n-k) / 2] (2)

Where N is the number of samples in the time domain, that is, the number of FFT points, n = 0, ..., N−1. By this calculation, the Fourier transform value Ir (k) of the current signal and the Fourier transform value _Vr (k) of the voltage signal can be separated from the output value of the FFT circuit 5. The separated Ir (k) and Vr (k) are input to the synthesis equalization unit 6. The following processing is the same as described in FIG.

Unlike the circuits in Figs. 5 and 6, this simplified synthesis diversity method has the advantage that only one FFT circuit 5 is required. In other words, the circuits of FIGS. 5 and 6 use two FFT circuits 5a and 5b, but do not actually have the processing power of one FFT circuit. However, in the circuit of Fig. 7, the current signal ir (t), which is N parallel signals, and the voltage signal vr (t) form one complex time signal, so one FFT circuit 5 Can be processed using. In addition, the Fourier transform value Ir (k) of the current signal and the Fourier transform value Vr (k) of the voltage signal can be separated from the output of the FFT circuit 5 by simple four arithmetic operations. Therefore, the circuit size of the entire FFT can be halved, the receiving apparatus can be simplified, and the same diversity effect as when the two FFT circuits are used can be obtained.

[0041] FIG. 8 is a block diagram showing a simplified combining diversity receiver of the OFDM scheme.

The difference between this simplified combining diversity receiving apparatus and the combining diversity receiving apparatus of FIG. 5 is that the current signal ir (t) passes through the N symbol serial-to-parallel conversion circuit 14a and the imaginary part 0 is omitted. N parallel signals, and the voltage signal vr (t) also becomes N parallel signals through the N symbol serial / parallel conversion circuit 14b. 〃2 "is not attached.

[0042] Unlike FIG. 5, the FFT circuit 5 includes a complexing unit 51, an FFT unit 52, and a calculation unit 53. The complexing unit 51 includes the N parallel circuits corresponding to the current signal ir (t). A complex time signal using a real signal and the N parallel real signals corresponding to the voltage signal vr (t)

u (t) = ir (t) + jvr (t)

make.

[0043] The FFT unit 52 performs a Fourier transform on this signal, and outputs a complex signal U (k) in the frequency domain. The calculation unit 53 uses the above-described equations (1) and (2) to calculate Ir (k), Find Vr (k).

As described above, the synthesis equalization unit 6 determines the weighting coefficients gi (k) and gv (k), multiplies them by the signals Ir (k) and Vr (k) after each Fourier transform, and adds them. The added signal R (k) is expressed as The

[0044] R (k) = gi (k) Ir (k) + gv (k) Vr (k)

The synthesis equalization unit 6 determines the weight coefficients gi (k) and gv (k) so as to maximize the SN ratio of the signal R (k) after the addition. The demodulator 7 converts the signal R (k) into an original code string, and the code string is N-symbol-parallel converted and extracted as information data.

FIG. 9 is a block diagram showing a simplified combined diversity receiver of the SCBT method.

[0045] The difference from the SCBT system diversity receiver of FIG. 6 is that the current signal ir (t) passes through the N-symbol serial-parallel converter circuit 14a and becomes N parallel signals with the imaginary part 0 omitted. The voltage signal vr (t) also passes through the N symbol serial / parallel conversion circuit 14b and becomes N parallel signals.

Unlike FIG. 6, the FFT circuit 5 includes a complexing unit 51, an FFT unit 52, and a calculation unit 53.

[0046] The complexing unit 51 uses the N parallel real signals corresponding to the current signal ir (t) and the N parallel real signals corresponding to the voltage signal vr (t) to generate a complex time signal.

u (t) = ir (t) + jvr (t)

The FFT unit 52 performs a Fourier transform on this function, and the calculation unit 53 obtains Ir (k) and Vr (k) using the equations (1) and (2) described above. The functions of the other synthesis equalization unit 6 and IFFT circuit 9 are the same as in FIG. As described above, the OFDM system and the SCBT system simplified combining diversity receiver can obtain the same diversity effect as when the two FFT circuits are used.

[0047] The embodiment of the present invention has been described above, but the embodiment of the present invention is not limited to the above-described embodiment. For example, the current detection unit and the voltage detection unit are combined with the diversity reception unit. It may be a receiving device. In addition, various modifications can be made within the scope of the present invention.

Claims

The scope of the claims

[1] In a method of communicating signals superimposed on a pair of lines,

Detecting the voltage and current of the line at the receiving end of the line,

A diversity receiving method in wired communication, wherein diversity detection is performed on a detected voltage signal and a detected current signal.

[2] In a method of communicating signals by superimposing signals on a pair of lines,

Detecting the voltage and current of the line at the receiving end of the line,

Fourier transform each of the detected current signal and voltage signal,

A diversity reception method in wired communication, wherein the Fourier-transformed current signal and voltage signal are synthesized for each frequency component.

3. The diversity reception method in wired communication according to claim 1, wherein the current signal and the voltage signal are combined with weights so that reception quality is optimal.

4. The diversity reception method in wired communication according to claim 3, wherein the reception quality is an SN ratio.

5. The diversity reception method in wired communication according to claim 2, wherein one of the voltage signal and the current signal is a real part and the other is an imaginary part to create a complex time signal and perform Fourier transform.

6. The diversity reception method in wired communication according to claim 1, wherein a reception signal having a better reception quality is selected from the voltage signal and the current signal.

7. The diversity reception method in wired communication according to claim 6, wherein the reception quality is an SN ratio.

8. The diversity reception method in wired communication according to claim 2, wherein a transmission method of the current signal and the voltage signal is an OFDM (Orthogonal Frequency Division Multiplex) method.

[9] The current signal and voltage signal transmission method is a single carrier block transmission method in which a guard block is added to a signal block composed of a plurality of symbols for transmission, and discrete frequency domain equalization is performed on the receiving side. The diversity reception method in wired communication according to claim 2.

10. The wired communication according to claim 1, wherein the line is a power line, a wiring in a car, or a telephone line. Diversity reception method in communication.

[11] In an apparatus for receiving signals superimposed on a pair of lines,

2. A receiving apparatus comprising: a diversity receiving unit that diversity-receives a current signal obtained by detecting the current of the line and a voltage signal obtained by detecting the voltage of the line.

[12] In an apparatus for receiving signals superimposed on a pair of lines,

A Fourier transform unit for Fourier transforming each of a current signal obtained by detecting a current at the receiving end of the line and a voltage signal obtained by detecting the voltage of the line into a frequency signal;

And a diversity receiver that combines the Fourier-transformed current signal and voltage signal for each frequency component.

13. The reception according to claim 11, wherein the current signal is detected through a current detection unit that detects a current in the line, and the voltage signal is detected through a voltage detection unit that detects a voltage at a reception end of the line. apparatus.