JP2002300134A - Communication unit and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication unit that can accurately determine whether or not a signal on a transmission line is transmitted to a present unit with a short symbol length. SOLUTION: The communication unit comprises a transmission means that modulates a particular code assigned to a communication opposite party and transmits a signal resulting from applying prescribed conversion processing to the modulation data and a reception means that demodulates the modulation data, correlates the demodulated data with a particular code assigned in advance to itself and determines that 'the signal on the transmission line is the signal addressed to itself' when the correlation value indicates a prescribed threshold or over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus employing a multi-carrier modulation / demodulation system, and more particularly to a DMT (Discrete Multi Tone) modulation / demodulation system and OF.
The present invention relates to a communication device and a communication method for performing data communication using an existing communication line by using a DM (Orthogonal Frequency Division Multiplex) modulation / demodulation method or the like.

[0002]

2. Description of the Related Art A conventional communication device will be described below. In recent years, "power line modems" that perform communication using existing power lines (light lines) without adding new communication lines for cost reduction and effective use of existing facilities have attracted attention. The power line modem performs various processes such as control of the product and data communication by networking electrical products such as inside and outside the home, buildings, factories, and stores connected by the power line.

At present, such power line modems include:
An apparatus using the SS (Spread Spectrum) method has been considered. For example, when the SS method is used as a power line modem, the transmitting side modulates predetermined information and further performs spread modulation using a “spreading code” to increase the signal band by several tens to several thousand times. Spread and send. On the other hand, the receiving side performs spread demodulation (despreading) using the same spreading code as the transmitting side, and then demodulates the despread signal into the predetermined information.

In this case, a spreading code desirable for the SS system generally has a sharp peak in the autocorrelation characteristic,
M-sequence (Maximum-length lin
earshift-register sequence) is used.

On the other hand, as a communication device employing a modulation / demodulation method different from the communication device employing the SS method, for example, there is a communication device employing a multicarrier modulation / demodulation method. Here, the operation of a conventional communication device employing the multi-carrier modulation / demodulation method will be described.

First, as a multi-carrier modulation / demodulation method,
The operation of the transmission system of a conventional communication device employing the OFDM modulation / demodulation method will be briefly described. For example, when performing data communication using the OFDM modulation / demodulation method, the transmission system performs tone ordering processing, that is, processing for allocating transmission data of a transmittable number of bits to a plurality of tones (multicarriers) in a predetermined frequency band. Do. More specifically, for example, tone0 to toneX (X
Is an integer indicating the number of tones), transmission data of a predetermined number of bits is allocated. The transmission data is multiplexed for each frame by performing the tone ordering process and the encoding process.

Further, the transmission system performs an inverse fast Fourier transform (IFFT) on the multiplexed transmission data,
The parallel data after the inverse fast Fourier transform is converted into serial data, then the digital waveform is converted into an analog waveform through a D / A converter, and finally the data is transmitted through a transmission path through a low-pass filter.

Next, a conventional communication apparatus employing an OFDM modulation / demodulation method as a multicarrier modulation / demodulation method is described below.
The operation of the receiving system will be briefly described. As above, OFD
When performing data communication using the M modulation / demodulation method, the reception system applies a low-pass filter to the reception data (the transmission data described above), and then converts an analog waveform into a digital waveform through an A / D converter, and sends the data to a time domain equalizer. To perform adaptive equalization processing in the time domain.

Further, the receiving system converts the data after the adaptive equalization processing in the time domain from serial data to parallel data, performs a fast Fourier transform on the parallel data, and then performs frequency domain equalization by a frequency domain equalizer. Is performed.

[0010] The data after the adaptive equalization processing in the frequency domain is converted into serial data by a composite processing (maximum likelihood composite method) and a tone ordering processing, and thereafter, rate conversion processing and FEC (forward error correction) are performed.
on: forward error correction), descrambling, CRC (cy
Processing such as clic redundancy check is performed, and finally the transmission data is reproduced.

As described above, in the conventional communication apparatus employing the OFDM modulation / demodulation method, high-rate communication is performed by utilizing, for example, good transmission efficiency and function flexibility which cannot be obtained by the CDMA or single carrier modulation / demodulation method. It is possible.

[0012]

SUMMARY OF THE INVENTION However,
In a conventional power line modem using the SS system, for example, a spectrum that fills a given band is transmitted, that is, a spectrum that fills a frequency band that can be used under legal regulations: 10 KHz to 450 KHz is transmitted. Therefore, there is a problem that it is difficult to coexist with other communication schemes, and that a transfer rate for a used band is low (extensibility is low).

Further, in the conventional communication apparatus employing the OFDM modulation / demodulation method, for example, from the viewpoint of “further improvement of transmission rate and demodulation accuracy”, it is necessary to determine whether or not the signal is transmitted to the own apparatus. However, there is a problem that there is room for improvement in the configuration.

[0014] The present invention has been made in view of the above, and even when a plurality of devices can communicate on the same network, whether a signal on a transmission path is a signal sent to the own device or not. It is an object of the present invention to obtain a communication apparatus capable of realizing an improvement in the transmission rate by accurately determining the transmission rate with a short symbol length.

[0015]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, in the communication device according to the present invention, it is assumed that a specific code for identifying a transmission path is pre-assigned, and a specific reference value (one of the modulation data) is further assigned. The second bit of the modulated data is determined from the result of comparison between the second bit of the modulated data and the first bit of the specific code assigned to the communication partner. The third bit of the modulated data is determined from the result of comparison with the third bit, and the same comparison process is repeated for the third bit and thereafter, thereby modulating the specific code assigned to the communication partner.
Transmitting means for transmitting a signal obtained by subjecting the modulated data to a predetermined conversion process on a transmission path; reproducing the modulated data from the signal on the transmission path; , The first bit of the demodulated data is determined from the comparison result, and the second bit of the modulated data is determined from the comparison result of the second and third bits of the modulated data.
By repeating the same comparison process until the last bit,
The modulation data is demodulated, and the correlation between the demodulated data and a specific code assigned to the own device in advance is performed. When the correlation value is equal to or more than a certain threshold, the signal on the transmission line is transmitted to the own device. Receiving means for determining that the signal is a transmitted signal. "

In the communication device according to the next invention,
Assuming that a specific code for identifying a transmission path has been assigned in advance, a comparison result between a specific reference value (first bit of modulation data) and the first bit of a specific code assigned to a communication partner To determine the third bit of the modulated data from the comparison result of the second bit of the modulated data with the second bit of the specific code assigned to the communication partner. By repeating the same comparison process, a transmission unit that modulates a specific code assigned to a communication partner and transmits a signal after subjecting the modulated data to a predetermined conversion process on a transmission path, The modulated data is reproduced from the signal on the road, and the first bit of the demodulated data is determined from the comparison result between the first bit and the second bit of the modulated data. The second bit of the modulated data is determined from the result of comparison between the first and third bits, and thereafter, the same comparison process is repeated until the last bit, thereby demodulating the modulated data. Taking the correlation, when the specific code having the highest correlation is the specific code assigned to the own device, receiving means for determining that "the signal on the transmission path is a signal sent to the own device", It is characterized by having.

In the communication apparatus (transmitter) according to the next invention, the modulation is performed based on the comparison result between the specific reference value (first bit of the modulation data) and the first bit of the specific code assigned to the communication partner. The second bit of the data is determined, and the third bit of the modulated data is determined from the result of comparison between the second bit of the modulated data and the second bit of the specific code assigned to the communication partner. By repeating the same comparison process, a modulation unit (corresponding to a second mapper 31 in an embodiment described later) for modulating a specific code assigned to a communication partner performs a predetermined conversion process on the modulated data. Output means for outputting the signal after the application on the transmission line (corresponding to IFFT4, P / S5, D / A6)
And the following.

In the communication apparatus (receiver) according to the next invention, reproducing means (corresponding to A / D16, S / P15, FFT14) for reproducing modulated data from a signal on a transmission line.
And the first bit of the demodulated data is determined from the comparison result of the first and second bits of the modulation data, and the second bit of the modulation data is determined from the comparison result of the second and third bits of the modulation data. After that, by repeating the same comparison processing until the last bit, a demodulating means for demodulating the modulated data (corresponding to the second demapper 12), the demodulated data and a specific code previously assigned to the own device are determined. Determination means (corresponding to the correlation detection circuit 33) for determining that the signal on the transmission path is a signal sent to the own device when the correlation value is equal to or greater than a certain threshold value. )
And the following.

In the communication device (receiver) according to the next invention, the reproducing means for reproducing the modulated data from the signal on the transmission line, and the comparison result between the first bit and the second bit of the modulated data. Determine the first bit of the demodulated data,
A demodulating means for demodulating the modulated data by determining a second bit of the modulated data from a comparison result between the second bit and the third bit of the modulated data, and thereafter repeating the same comparison processing until the last bit; Correlation calculation means (corresponding to the correlation detection circuit 33) for correlating the demodulated data with all the specific codes, and when the specific code having the highest correlation is the specific code assigned to the own device, the "signal on the transmission path" Is a signal sent to its own device "(corresponding to the control circuit 10).

In the communication method according to the next invention,
The second bit of the modulated data is determined from the comparison result of the specific reference value (the first bit of the modulated data) and the first bit of the specific code assigned to the communication partner, and the second bit of the modulated data and the communication partner are determined. 2 of the specific code assigned to
A modulation step of modulating a specific code assigned to a communication partner by determining the third bit of the modulated data from the comparison result with the bit and repeating the same comparison processing for the third bit and thereafter, An output step of outputting a signal after performing a predetermined conversion process on the transmission path, a reproduction step of reproducing the modulation data from the signal on the transmission path, and a first bit and a second bit of the modulation data. , The first bit of the demodulated data is determined from the comparison result, the second bit of the modulation data is determined from the comparison result of the second bit and the third bit of the modulation data, and the same comparison process is repeated until the last bit. Accordingly, a demodulation step of demodulating the modulated data, and a correlation between the demodulated data and a specific code assigned to the own device in advance, and a correlation value is provided. If it is certain threshold or more,
A determination step of determining that "the signal on the transmission path is a signal transmitted to the own device".

In the communication method according to the next invention,
The second bit of the modulated data is determined from the comparison result of the specific reference value (the first bit of the modulated data) and the first bit of the specific code assigned to the communication partner, and the second bit of the modulated data and the communication partner are determined. 2 of the specific code assigned to
A modulation step of modulating a specific code assigned to a communication partner by determining the third bit of the modulated data from the comparison result with the bit and repeating the same comparison processing for the third bit and thereafter, An output step of outputting a signal after performing a predetermined conversion process on the transmission path, a reproduction step of reproducing the modulation data from the signal on the transmission path, and a first bit and a second bit of the modulation data. , The first bit of the demodulated data is determined from the comparison result, the second bit of the modulation data is determined from the comparison result of the second bit and the third bit of the modulation data, and the same comparison process is repeated until the last bit. A demodulating step of demodulating the modulated data; a correlation calculating step of correlating the demodulated data with all specific codes; When the over de it was specific code allocated to the own apparatus, a determination step of determining that, "the signal on the transmission line is a signal sent to the own device"
It is characterized by including.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a communication device and a communication method according to the present invention will be described in detail with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1 In the present embodiment, as a communication device using an existing power line, for example, a power line modem employing a multi-carrier modulation / demodulation method will be described. In a power line modem, for example, an OFDM (Orthogonal Frequency Division Multip
lexing) When transmitting and receiving signals, 256 complex IFFs
Using T, 128 DQPSK data or MQ
Convert AM data to time axis data. Therefore, when the carrier interval is set to Δf = 4.3125 KHz, a band from 0 to 552 KHz is used.

Further, in the present embodiment, when transmitting and receiving an OFDM signal of 128 tones, a power line modem operating in a low-speed mode includes five narrow-band carrier frequency carriers arranged every 16 tones, for example, Tone 3
Data communication is performed using 2, 48, 64, 80, and 96, and the power line modem operating in the high-speed mode performs data communication using the remaining tones.

FIG. 1 is a diagram showing a configuration example of a communication device according to the present invention. In FIG. 1, 1 is a framing circuit, 2 is a first mapper, and 4 is an inverse fast Fourier transform (IFFT) circuit.
m), and 5 is a parallel / serial conversion circuit (P /
S), and 6 is a digital / analog conversion circuit (D /
A), 7 is a transmission line (power line), 8 is a coupling circuit, 10 is a control circuit, 11 is a deframing circuit, 12 is a first demapper, and 14 is a fast Fourier. Transformation circuit (FFT: Fast Fourier Transfor
m), and 15 is a serial / parallel conversion circuit (S /
P), and 16 is an analog / digital conversion circuit (A
/ D), 17 is a carrier detector, 21 is a symbol boundary determination value calculator, 22 is a symbol boundary determination unit, 23 is a synchronous tone selector, and 31 is a second mapper. Yes, 32 is a second demapper, 33
Is a correlation detection circuit.

The framing circuit 1, the first mapper 2, the IFFT 4, the P / S 5, the D / A 6, and the second mapper 31 constitute a transmission system, and the A / D 16, S / P 15, FF
T14, first demapper 12, deframing circuit 1
1, a symbol boundary determination value calculator 21, a symbol boundary determiner 22, a synchronous tone selector 23, a second demapper 32,
The correlation detection circuit 33 forms a reception system.

Here, basic operations of the transmission system and the reception system will be described with reference to the drawings. First, the operation of the transmission system will be described. For example, when transmission data is input from a data processing device (not shown) connected to the communication device (power line modem), the framing circuit 1 performs a framing process shown in FIG. 1 to the mapper 2. Then, in the first mapper 2, the received frame is referred to as “tone ordering selection information” and “turbo code length selection information” from the control circuit 10.
Mapping (including DQPSK modulation, M-QAM modulation, turbo coding, power distribution control, etc.) is performed using “bitmap selection information”, “power distribution selection information” and the like, and the result is represented by I
Output to FFT4.

In IFFT4, all received tones (tones 48, 64, and
(Other than 80) is subjected to inverse Fourier transform to convert frequency axis data into time axis data and output it to P / S5.

In P / S5, the parallel data output from IFFT4 is converted into serial data, and the serial data is output to D / A6.
At 6, the digital / analog conversion is performed on the serial data, and the analog signal is transmitted to another communication device (not shown) connected to the power line 7 via the coupling circuit 8 and the power line 7.

Next, the operation of the receiving system will be described.
Here, for convenience of explanation, since only one communication device is connected to the transmission path 7, the description will be made using the configuration of the receiving system in FIG. In the receiving system described below,
It is confirmed that symbol synchronization is established using a pilot tone constantly transmitted from a communication device serving as a clock master (actually, using a pilot frame transmitted intermittently when communication is not being performed). It is assumed.

First, when multicarrier data is transmitted from the transmission system as described above, the reception system of another communication device performs an operation reverse to the operation of the transmission system to demodulate the data. More specifically, all the multi-carrier data sent from the communication device on the transmission side is fetched via the coupling circuit 8, and the A / D 16 performs analog / digital conversion. Subsequently, the carrier detector 17 detects a carrier detection field by carrier sense and tone test.

Thereafter, the S / P 15 converts the serial data converted to digital data into parallel data based on the symbol timing at which synchronization is established,
The data is output to FFT14.

The FFT 14 performs a Fourier transform on the parallel data to convert the multicarrier signal on the time axis into data on the frequency axis, and outputs the frequency axis data to the first demapper 12. Thereafter, the first demapper 12 demodulates the received frequency data by using “FEQ coefficient information”, “information on turbo decoding”, “bitmap information”, “tone ordering selection information” specified by the control circuit 10, and the like. .

Finally, the deframing circuit 11 performs a deframing process for cutting out only the data in the transmission frame (see FIG. 2) from the demodulated data.
It generates reception data and outputs the reception data to a device (not shown) connected to the communication device. Note that the deframing process is a process opposite to the framing process by the framing circuit 1, and separates a preamble and a physical layer header to be described later from a frame of the primary demodulated data, and synthesizes only the physical layer payload. processing,
That is, it refers to a process of reconstructing received data into original transmission data.

FIG. 2 is a diagram showing the structure of a frame generated by the framing process by the framing circuit 1. As shown in FIG. The frame shown in FIG. 2 includes a preamble field (AGC) which is an area of a signal for carrier detection, a code (ID) indicating a transmission path, a sample clock / symbol clock synchronization signal (PT1, PT2), and the like. The framing circuit 1 includes a header field, a logical data boundary identification code, a bitmap match / mismatch detection code, a command field, control information such as a group code, and a physical layer payload field including transmission data. , And after being modulated in the above-described processing, is output to the transmission path 7.

The frame on the transmission line is received by all communication devices connected to the transmission line, and the control circuit 10
Then, only when the received signal is identified and the code matches the own code, it is determined that the data transmitted on the transmission path is addressed to itself, and the contents of the subsequent payload portion are understood. If it is determined that it is not addressed to itself, no operation is performed.

FIG. 3 is a diagram showing tones used by the communication device operating in the low-speed mode for data communication and tones used by the communication device operating in the high-speed mode for data communication. For example, 128 lines at 4.3125 kHz intervals (#
0 to # 127), the communication device operating in the low-speed mode performs data communication using the illustrated five tones selected at intervals of 16 lines, and performs communication in the high-speed mode. Then, data communication is performed using other tones.

FIG. 4 is a diagram showing the state of the frame on the transmission path and the unit of the symbol input to the FFT. For example, in the present embodiment, as shown in FIG. 4, the symbols constituting the frame include a cyclic prefix (CP) of 16 samples,
It consists of a data portion of 6 samples and one symbol is 27
There are two samples. Therefore, the receiving side demodulates the data in a state where the CP inserted at a known timing is deleted (corresponding to “to demodulation FFT” in FIG. 4). The data portion is a minimum unit of communication, and represents a composite wave of all tones to be transmitted in a 256-point sample. The CP is inserted between symbols in order to prevent inter-symbol interference, and is obtained by duplicating and pasting the last 16 samples of the data portion. It becomes a waveform.

Here, a method of establishing symbol synchronization when data communication is performed between the communication devices will be described in detail. Here, the symbol frequency F is set to F = 4 kHz,
The sampling frequency S of D / A6 and A / D16 is S
= 1.024 MHz. In this case, a signal for one symbol time is composed of S / F (256 samples) + CP (16 samples) = 272 samples. Also, the symbol here is the minimum unit of communication,
For example, a multi-tone composite wave used for communication
This is represented by two sample data. Also, I
When FFT4 and FFT14 correspond to 256 samples, the tone frequencies that can be generated are Fxx (x = 1 to 1).
28), and 128 tones are available.

In such a state, the receiving system of the communication device first establishes symbol synchronization using the pilot tone transmitted by the clock master at the time of start-up and when data communication is not being performed. Be prepared to start. Specifically, first, A /
D16 captures the signal on the transmission line by performing 272-point sampling. Then, the symbol boundary determination value calculation unit 21 performs an operation for establishing symbol synchronization with another communication device using the sampling data of the pilot tone after the A / D conversion.

The symbol boundary determination value calculator 21 calculates a determination value required for determining a symbol boundary using the sampling data of the pilot tone. The synchronous tone selector 23 selects at least one pilot tone from a plurality of tones according to an instruction from the control circuit 10. If the frequency of the selected pilot tone is, for example, M times the symbol frequency (M = 2
4, 40, 56, 72, 88), the symbol boundary determination value calculator 21 calculates the past S / F + CP = 272.
The sample data is buffered, and a symbol boundary determination value described later is calculated. However, here, the first content of the buffer is D ₀ , and the last content is D _{0.
(S / F + CP) -1} . Each time new sample data is obtained, the latest S / F + CP = 27
It is calculated using two sample data.

Next, the symbol boundary determiner 22 searches for the timing at which the maximum value of the symbol boundary determination values for the past S / F + CP = 272 has occurred, and uses the searched timing to determine the symbol. Establish synchronization.

FIG. 5 is a diagram showing a specific example of a method for establishing symbol synchronization between communication devices. Here, as the pilot tone, for example, a 24 × tone (tone 24)
Is selected (M = 24). Note that, as described above, the pilot tone is a signal having the same phase in a symbol cycle unit.

FIG. 5A shows a composite wave of a plurality of tones.
It expresses only the pilot tone. FIG.
In (a), the pilot tone includes a sine wave signal of 25 cycles (including CP) in one symbol period.
When one symbol is sampled at S / F + CP = 272 points, 16 samples have a period of 1.5, and have a value whose sign is inverted every 16 samples.

First, in the symbol boundary judgment value calculator 21, every time new sample data is obtained, the latest S / S
F + CP = using 272 sample data, and 16
Inverts the value in sample units and performs synchronous addition. That is, as shown in the figure, the sample value is inverted every 16 samples, and synchronous addition is performed within a range of one symbol length.

FIG. 5B is a diagram showing an example of the calculation range of the symbol boundary judgment value, FIG. 5C is a diagram showing an example of the synchronous addition result, and FIG. FIG. 14 is a diagram illustrating a result of addition of absolute values of sample data in a result of synchronous addition, that is, a symbol boundary determination value. As shown, when the calculation range of the symbol boundary determination value is A (FIG. 5)
(See (b)), the pilot tone signal is enhanced,
It is possible to obtain a synchronous addition result for 1.5 cycles in which the amplitude becomes 17 times (see A ′ in FIG. 5C). In this case, the symbol boundary determination value becomes the maximum (see FIG. 5D). Then, as the calculation range of the symbol boundary determination value deviates from A, the symbol boundary determination value gradually decreases.
Note that signal components of tones other than the selected pilot tone (M = 24) are canceled by the above-described synchronous addition, and the value becomes 0.

On the other hand, when the calculation range of the symbol boundary determination value is B
5 (see FIG. 5B), since the first half (D _{0 to} D ₁₃₅ ) and the second half (D _{136 to} D ₂₇₂ ) of the 272-point signal are in-phase signals, the synchronous addition (in units of 16 samples) The signal of the pilot tone is canceled by the inversion, and a synchronous addition result for 1.5 cycles in which the amplitude becomes 0 can be obtained (see B ′ in FIG. 5C). In this case, the symbol boundary determination value becomes minimum (see FIG. 5D).

Then, the symbol boundary judgment unit 22 that has received the output from the symbol boundary judgment value calculator 21
The timing at which the symbol boundary determination value over the symbol period is maximum is detected, and this is used as the symbol timing between the communication devices.

As described above, when symbol synchronization is established between communication apparatuses, pilot tones (tones 24, 40, 56, 72, 8) satisfying 16n (n is a natural number) +8
The symbol synchronization process is performed using 8). More specifically, the value of the pilot tone is inverted in units of 1/17 symbol length (16 samples), and synchronous addition of sampling data is performed within one symbol length range. The timing at which the sum of the absolute values of the sampling points in, that is, the symbol boundary determination value, becomes maximum is defined as the symbol timing between the communication devices.

In the above description, the basic operation of the communication device and the method of establishing symbol synchronization between the communication devices have been described. In the following description, a configuration for determining whether a signal on a transmission path is a signal transmitted to the own device will be described. In the present embodiment, it is determined whether or not the signal on the transmission path is a signal sent to its own device using the ID (for one symbol) in the physical layer header shown in FIG.

First, the operation of the transmission system will be described. For example, in the transmission system, when transmission data is input from a data processing device (not shown) connected to the communication device, as described above, the first mapper 2 causes the frame after the framing process shown in FIG. Is mapped to a predetermined tone, and the mapping result is output to IFFT4. However, at this time, the second mapper 31 uses a code “ID” for identifying a transmission path in the frame, that is,
Modulation processing as described below is performed on a predetermined orthogonal code previously assigned to a communication partner. FIG.
FIG. 4 is a diagram showing a Hadamard sequence of 32 rows × 32 columns, which is an example of the orthogonal code.

FIG. 7 is a diagram showing a modulation method when the Hadamard sequence assigned to the communication partner is "10110...". First, the second mapper 31 sets the first bit of the modulated data as the reference value: 1 (fixed), and compares this reference value with the first bit of the Hadamard sequence. In the present embodiment, the next bit of the modulated data is set to 1 when the data of the bit to be compared is equal, and the next bit of the modulated data is set to 0 when the data of the bit to be compared is different. Therefore, in the present embodiment, since the reference value is 1 and the first bit of the Hadamard sequence is 1, the second bit of the modulated data is 1 as shown in the figure.

Thereafter, the comparison processing (comparison processing of the second bit, the third bit,...) Is repeated in the same procedure as described above, and the second mapper 31 outputs “11” as modulated data.
0001 ... ". Then, the modulation data is mapped to a plurality of tones excluding the reserved tone and the pilot tone in the low-speed mode, and output to the subsequent IFFT 4.

Thereafter, the IFFT 4 converts the frequency axis data into time axis data by performing an inverse Fourier transform on all the received tones.

On the other hand, in the receiving system of the communication device, all the multi-carrier data sent from the communication device on the transmission side is fetched via the coupling circuit 8, and the A / D 16 performs analog / digital conversion. Subsequently, the carrier detector 17 detects a carrier detection field by carrier sense and tone test. Here, the signal for carrier detection (AGC) is determined by the carrier detector 17.
When it is determined that there is a frame, it is determined whether or not the frame being received is a frame for the own apparatus by using the subsequent sampling data (ID).

More specifically, first, the S / P 15 converts the serial data (ID portion in the frame: one symbol) converted into digital data into parallel data based on the current symbol synchronization clock. Then, the data is output to the FFT 14. After that, the FFT 14 performs a Fourier transform on the received parallel data, and converts the multicarrier signal on the time axis into data on the frequency axis. Then, those frequency axis data are
Is output to the demapper 32.

The second demapper 32 demodulates the received frequency axis data in a procedure reverse to the above-mentioned modulation processing.
FIG. 8 is a diagram illustrating a demodulation method when the received frequency axis data (modulated data) is “110001...”, For example. First, in the second demapper 32,
The first bit and the second bit of the received frequency axis data are compared. In the present embodiment, the next bit of the modulated data is set to 1 when the data of the bit to be compared is equal, and the next bit of the modulated data is set to 0 when the data of the bit to be compared is different. Therefore, in the present embodiment, the first bit is 1 and the second bit is 1, so that the first bit of the demodulated data is 1 as shown.

Thereafter, the comparison process (the comparison process of the second bit and the third bit, the comparison process of the third bit and the fourth bit,...) Is repeated in the same procedure as described above, and the second demapper 32 outputs the demodulated data as the demodulated data. "10110 ..." is obtained. Then, it outputs the demodulated data to the subsequent correlation detection circuit 33.

The correlation detection circuit 33 calculates a correlation between the received demodulated data and an orthogonal code (Hadamard sequence) assigned to the apparatus in advance, and when the correlation value is equal to or greater than a certain threshold value, a "transmission" The signal on the road is the signal sent to the own device. ", And the result of the determination is notified to the control circuit 10. In the present embodiment, the correlation detection circuit 33 performs the above-described determination processing. However, the present invention is not limited to this. For example, the correlation detection circuit 33 performs correlation between the received demodulated data and all Hadamard sequences, The Hadamard sequence having the highest correlation may be notified to the control circuit 10, and the control circuit 10 may perform the above-described determination processing.

As described above, in the present embodiment, the second mapper 31 that modulates the orthogonal code assigned in advance to specify the communication partner is added to the configuration on the transmission side.
A second demapper 32 for demodulating modulated data and a correlation detecting circuit 33 for judging whether a frame being received is a frame addressed to the own device using the demodulated data are provided in the configuration of the receiving side.
Add. Thus, it is possible to accurately determine whether a signal on the transmission path is a signal transmitted to the own apparatus with a short symbol length. In addition, since the header portion that causes a decrease in throughput can be shortened, the transmission rate can be significantly improved.

[0061]

As described above, according to the present invention, according to the present invention, means for modulating a pre-assigned specific code for specifying a communication partner is added to the configuration of the transmitting side, and A means for demodulating the modulated data and a means for determining whether the frame being received is a frame addressed to the own apparatus using the demodulated data are added. With this, it is possible to accurately determine whether the signal on the transmission path is a signal sent to the own device with a short symbol length,
This has the effect. Further, since the header portion which causes a decrease in throughput can be shortened, there is an effect that the transmission rate can be greatly improved.

According to the next invention, a means for modulating a specific code assigned in advance to specify a communication partner is added to the structure on the transmitting side, and a means for demodulating modulated data is provided on the structure on the receiving side. A means for correlating all specific codes and demodulated data, and further, a function of determining whether or not the frame being received is a frame addressed to the own apparatus using the specific code having the highest correlation. Was added. As a result, it is possible to accurately determine whether the signal on the transmission path is a signal transmitted to the own device with a short symbol length. Further, since the header portion which causes a decrease in throughput can be shortened, there is an effect that the transmission rate can be greatly improved.

According to the next invention, a modulating means for modulating a specific code assigned in advance to specify a communication partner is added to the configuration on the transmitting side. As a result, there is an effect that the receiving communication device can accurately determine whether the signal on the transmission path has been transmitted to the own device with a short symbol length.

According to the next invention, a demodulating means for demodulating the modulated data and a judging means for judging whether or not the frame being received is a frame addressed to the own apparatus using the demodulated data are added to the configuration on the receiving side. Configuration. As a result, whether the signal on the transmission path is a signal sent to the own device,
This has the effect that accurate determination can be made with a short symbol length.

According to the next invention, a demodulating means for demodulating the modulated data, a correlation calculating means for correlating the demodulated data with all the specific codes, and a specific code having the highest correlation are provided in the receiving apparatus. If the specific code is assigned to the device, a determination means for determining that "the signal on the transmission path is a signal transmitted to the own device" is added. As a result, it is possible to accurately determine whether the signal on the transmission path is a signal transmitted to the own device with a short symbol length.

According to the next invention, a modulation step of modulating a specific code allocated in advance to specify a communication partner, a demodulation step of demodulating modulated data, and a frame being received using the demodulated data are performed. And a determining step of determining whether the frame is addressed to the own device. As a result, it is possible to accurately determine whether the signal on the transmission path is a signal transmitted to the own device with a short symbol length. Further, since the header portion which causes a decrease in throughput can be shortened, there is an effect that the transmission rate can be greatly improved.

According to the next invention, a modulation step of modulating a specific code assigned in advance to specify a communication partner, a demodulation step of demodulating modulated data, and correlation between all specific codes and demodulated data are performed. A correlation calculation step and a determination step of determining whether the frame being received using the specific code having the highest correlation is a frame addressed to the own apparatus are added. As a result, it is possible to accurately determine whether the signal on the transmission path is a signal transmitted to the own device with a short symbol length. Further, since the header portion which causes a decrease in throughput can be shortened, there is an effect that the transmission rate can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a communication device according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a frame generated by a framing process.

FIG. 3 is a diagram showing tones used for data communication.

FIG. 4 is a diagram illustrating a state of a frame on a transmission path and a unit of a symbol input to an FFT.

FIG. 5 is a diagram illustrating a specific example of a method of establishing symbol synchronization between communication devices.

FIG. 6 is a diagram showing a Hadamard sequence of 32 rows × 32 columns, which is an example of an orthogonal code.

FIG. 7 is a diagram illustrating a modulation method when a Hadamard sequence assigned to a communication partner is “10110.

FIG. 8 shows that the received modulation data is “110001.
It is a figure which shows the demodulation method when it is "."

[Explanation of symbols]

Reference Signs List 1 framing circuit, 2 first mapper, 4 inverse fast Fourier transform circuit (IFFT), 5 parallel / serial converter circuit (P / S), 6 digital / analog converter circuit (D / A), 7 transmission line (power line) , 8 coupling circuit, 10 control circuit, 11 deframing circuit, 12
1st demapper, 14 fast Fourier transform circuit (FF
T), 15 serial / parallel conversion circuit (S / P),
16 analog / digital conversion circuit (A / D), 17
Carrier detector, 21 symbol boundary judgment value calculator,
22 symbol boundary determiner, 23 synchronous tone selector,
31 second mapper, 32 second demapper, 33 correlation detection circuit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hidenobu Fukushima 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Tsuyoshi Kobayashi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F term in Ryo Denki Co., Ltd. (reference) 5K022 DD01 DD13 DD18 DD19 DD23 DD33 5K046 AA03 BA06 BB05 PS03 PS06 PS42 YY01

Claims (7)

[Claims] In a communication apparatus to which a specific code for identifying a transmission path is assigned in advance, a specific reference value (first bit of modulation data) and a first bit of a specific code assigned to a communication partner are used. The second bit of the modulation data is determined from the result of the comparison, and the second bit of the modulation data and the second bit of the specific code
The third bit of the modulated data is determined from the result of comparison with the bit, and the same comparison process is repeated for the third bit and thereafter, thereby modulating the specific code assigned to the communication partner. Transmitting means for transmitting the signal after the predetermined conversion processing to the transmission path; reproducing the modulation data from the signal on the transmission path; and demodulating data from a comparison result between the first bit and the second bit of the modulation data. Is determined, and the second bit of the modulated data is determined.
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, the same comparison process is repeated until the last bit, thereby demodulating the modulated data. A communication device comprising: a receiving unit that determines that “the signal on the transmission path is a signal transmitted to the own device” when the value is equal to or more than a predetermined threshold value. 2. A communication apparatus to which a specific code for identifying a transmission path is assigned in advance, wherein a specific reference value (first bit of modulation data) and a first bit of a specific code assigned to a communication partner are used. The second bit of the modulation data is determined from the result of the comparison, and the second bit of the modulation data and the second bit of the specific code
The third bit of the modulated data is determined from the result of comparison with the bit, and the same comparison process is repeated for the third bit and thereafter, thereby modulating the specific code assigned to the communication partner. Transmitting means for transmitting the signal after the predetermined conversion processing to the transmission path; reproducing the modulation data from the signal on the transmission path; and demodulating data from a comparison result between the first bit and the second bit of the modulation data. Is determined, and the second bit of the modulated data is determined.
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, by repeating the same comparison processing until the last bit, the modulated data is demodulated, the demodulated data is correlated with all the specific codes, and the specific code having the highest correlation is transmitted to the own device. A communication device, comprising: receiving means for determining that the signal on the transmission path is a signal sent to the own device when the specific code is assigned. 3. A communication device that operates as a transmitter, wherein a second bit of modulated data is obtained from a comparison result between a specific reference value (first bit of modulated data) and a first bit of a specific code assigned to a communication partner. Is determined, and the second bit of the modulated data and 2 of the specific code assigned to the communication partner are determined.
Modulating means for modulating a specific code assigned to a communication partner by determining a third bit of the modulated data from the result of comparison with the bit and repeating the same comparison process for the third and subsequent bits; Output means for outputting, on a transmission path, a signal obtained by subjecting a signal to a predetermined conversion process. 4. A communication device operating as a receiver, comprising: a reproducing unit for reproducing modulated data from a signal on a transmission path; and a first bit of demodulated data based on a comparison result between a first bit and a second bit of the modulated data. Is determined, and 2 of the modulation data is determined.
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, by repeating the same comparison processing until the last bit, a demodulating means for demodulating the modulated data, and a correlation between the demodulated data and a specific code previously assigned to the own device, When the value is equal to or greater than a certain threshold, the communication device comprises: a determination unit that determines that “the signal on the transmission path is a signal transmitted to the own device”. 5. A communication device that operates as a receiver, comprising: a reproducing unit that reproduces the modulated data from a signal on a transmission path; and 1 bit of demodulated data based on a comparison result between a first bit and a second bit of the modulated data. Determine the eye and 2 of the modulated data
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, the same comparison process is repeated until the last bit, thereby demodulating the demodulated data, correlation calculating means for correlating the demodulated data with all the specific codes, When the high specific code is a specific code assigned to the own device, a determination unit for determining that “the signal on the transmission path is a signal transmitted to the own device” is provided. Communication device. 6. A communication method in which a specific code for identifying a transmission path is assigned to each communication device in advance, wherein a specific reference value (first bit of modulated data) and a communication partner are assigned. The second bit of the modulated data is determined from the result of comparison with the first bit of the specific code, and the second bit of the modulated data and the second bit of the specific code assigned to the communication partner are determined.
A modulation step of modulating a specific code assigned to a communication partner by determining a third bit of the modulation data from the comparison result with the bit and repeating the same comparison processing for the third bit and thereafter; An output step of outputting a signal after performing a predetermined conversion process on the transmission path, a reproduction step of reproducing the modulation data from the signal on the transmission path, and a first bit and a second bit of the modulation data. From the comparison result, the first bit of the demodulated data is determined.
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, by repeating the same comparison processing until the last bit, a demodulation step of demodulating the modulated data, and a correlation between the demodulated data and a specific code previously assigned to the own device is obtained. A determining step of determining that "the signal on the transmission path is a signal sent to the own device" when the value is equal to or greater than a certain threshold value. 7. A communication method in which a specific code for identifying a transmission path is assigned to each communication device in advance, wherein a specific reference value (first bit of modulation data) and a communication partner are assigned. The second bit of the modulated data is determined from the result of comparison with the first bit of the specific code, and the second bit of the modulated data and the second bit of the specific code assigned to the communication partner are determined.
A modulation step of modulating a specific code assigned to a communication partner by determining a third bit of the modulation data from the comparison result with the bit and repeating the same comparison processing for the third bit and thereafter; An output step of outputting a signal after performing a predetermined conversion process on the transmission path, a reproduction step of reproducing the modulation data from the signal on the transmission path, and a first bit and a second bit of the modulation data. From the comparison result, the first bit of the demodulated data is determined.
From the comparison result of the bit and the third bit, 2
The bit number is determined, and thereafter, the same comparison process is repeated until the last bit, thereby demodulating the modulated data, a correlation calculating step of correlating the demodulated data with all the specific codes, and When the high specific code is the specific code assigned to the own device, determining that "the signal on the transmission path is a signal sent to the own device". Communication method.