JP5974338B2 - Communication device, in-home device, communication system, signal-to-noise ratio margin setting method, and program - Google Patents

Description

  The present invention relates to a communication device, a home device, a communication system, a signal-to-noise ratio margin setting method, and a program, and more particularly, a communication device that communicates with a home device using a telephone line, the home device, the communication device, and the home device. A signal-to-noise ratio margin setting method in a communication apparatus, and a program for controlling the communication apparatus.

  An xDSL (x Digital Subscriber Line) method for performing high-speed data communication using an existing telephone line (metal cable) is, for example, VDSL (Very high-bit-rate DSL). ) And ADSL (Asymmetric DSL).

  In the VDSL system, for example, a collective device provided in an MDF (Main Distributing Frame) room of a collective housing communicates with a customer premises equipment (CPE) in each home. In the ADSL system, the station side device communicates with each home device (subscriber side device) in each home.

  In addition, the xDSL modulation scheme includes a DMT (Discrete Multi-Tone) modulation scheme that performs communication by dividing a transmission frequency band to be used into a plurality of fine bands. In a multicarrier communication system using the DMT modulation method, training for checking a line state between communication apparatuses connected to each other is performed before starting data communication. In this training, a signal-to-noise ratio (hereinafter also referred to as SNR (Signal to Noise Ratio)) is measured (observed) for each of the divided subchannels, and subcarriers that are subchannel carriers are measured according to the measurement results. Sets the distribution of the number of bits allocated to Thereby, the communication speed corresponding to the line state is automatically set (best effort method). When the link (connection) between the communication devices is established after the training is completed, data communication is started at the set communication speed.

  In the xDSL apparatus, the number of bits is allocated to each subcarrier so that the communication signal satisfies the predetermined reception quality under the condition of SNR obtained by subtracting a predetermined margin value (hereinafter also referred to as SNR margin) from the measured SNR. To do. That is, the SNR margin is a margin value for preventing transmission errors. By setting the SNR margin, it is possible to adjust the tolerance of the communication signal against transmission errors.

  Incidentally, in recent years, standards such as OLR (On Line Reconfiguration) have been defined. The OLR is a function that allows a modulation scheme used when digitally modulating subcarriers (carrier waves) constituting a multicarrier to be changed while data communication (communication after initial setting) is online. In other words, OLR is a function that dynamically changes the communication speed during data communication by changing the modulation method.

  When the collective device having the OLR function communicates with the in-home device having the OLR function, the modulation method can be dynamically changed according to the actual environment as described above, and therefore, when communicating with the in-home device not having the OLR function. In comparison, the SNR margin can be set smaller. For this reason, the collective device can increase the communication speed when communicating with the in-home device having the OLR function as compared with the case of communicating with the in-home device not having the OLR function.

  Chapter 12 Section 3 of Non-Patent Document 1 defines an initial setting procedure performed during the start of data communication in the VDSL system (12.3 Initialization Procedure). The training is one of the procedures included in the initial setting procedure. Moreover, the content of OLR is described in Chapter 13 of the same document (13 On-line reconfiguration).

  Non-Patent Document 2 discloses an SRA (Seamless Rate Adaptation) function which is a part of the OLR function. Non-Patent Document 3 discloses an SOS function which is a part of the OLR function. Note that the “SRA function” is a function that gently changes the communication speed when the noise change is small. The “SOS function” is a function that rapidly decreases the communication speed when the noise change is large.

ITU-T Recommendation G.993.2 (02/2006) Very high speed digital subscriber line transceivers 2 (VDSL2) ITU-T Recommendation G.993.2 (04/2007) Very high speed digital subscriber line transceivers2 (VDSL2) Amendment 1 ITU-T Recommendation G.993.2 (08/2008) Very high speed digital subscriber line transceivers2 (VDSL2) Amendment 3

  However, when the aggregation device having the OLR function communicates with a home device that does not have the OLR function, if the SNR margin is set to be small, the modulation method cannot be dynamically changed, and thus a communication error may occur. Get higher.

  The present invention has been made in view of the above-described problems, and its purpose is to provide an OLR function in a communication system including a home device having an OLR function and a home device having no OLR function. Collective device capable of reducing occurrence of communication error while utilizing, communication device including communication device and communication device, method for setting signal to noise ratio margin in communication device, and program for controlling communication device It is to provide.

  According to an aspect of the present invention, a communication device performs data communication with a home device using a multi-carrier method using a communication line. The communication device modulates the modulation method used when digitally modulating the subcarriers constituting the multicarrier while the data communication is online, and the home device is modulated online before starting the data communication. Setting means for setting a signal-to-noise ratio margin in data communication based on whether or not a function of changing the method is provided.

  Preferably, the setting means determines whether or not the in-home device has a function before starting the training for checking the state of the communication line. The communication device further includes notification means for notifying the in-home device of the set signal-to-noise ratio margin before starting the training.

  Preferably, the communication device further includes receiving means for receiving information indicating whether or not the home device has a function from the home device in a handshake before training. The setting means determines whether or not the in-home device has a function based on the information.

  Preferably, the communication device further includes storage means for storing data representing whether each of the plurality of in-home devices has a function. The setting means determines whether the in-home device has a function based on the data and information transmitted from the in-home device in the handshake before training.

  Preferably, the communication device acquires data from a communication device that is communicably connected to the communication device, and stores the data in the storage device.

  Preferably, the information includes identification information of the home device. The setting means determines whether the in-home device has a function using the identification information.

  Preferably, the information includes information representing a model name of the home device. The setting means determines whether or not the in-home device has a function using information representing the model name.

  Preferably, the information includes version information of firmware installed in the home device. The setting means determines whether the in-home device has a function using the version information.

  Preferably, the communication apparatus further includes a determination unit that determines a modulation scheme using a set signal-to-noise ratio margin before starting data communication.

  Preferably, the determining means uses the signal-to-noise ratio margin set in training and the signal-to-noise ratio measured by the in-home device in the down-communication from the communication device to the in-home device. To decide.

  Preferably, the determining means uses the signal-to-noise ratio margin set in the training and the signal-to-noise ratio measured by the communication device in the uplink communication from the in-home device to the communication device, and uses the modulation scheme in the uplink communication. To decide.

  Preferably, when the setting unit has a function, the first value of the first value and the second value larger than the first value is set as the signal-to-noise ratio margin. If the setting means does not have a function, the setting means sets the second value as the signal-to-noise ratio margin.

  According to another aspect of the present invention, the in-home device performs data communication with the communication device using a communication line. Based on whether the in-home device has a function of changing the modulation method when digitally modulating the subcarriers constituting the multicarrier while the data communication is online before starting the data communication. In the training for confirming the state of the communication line before the data communication and the receiving means for receiving the signal-to-noise ratio margin in the data communication set by the communication device from the communication device, the downlink from the communication device to the home device Measurement means for measuring a signal-to-noise ratio in communication, calculation means for calculating the number of bits allocated to subcarriers in downlink communication using the signal-to-noise ratio margin and the measured signal-to-noise ratio in training, and calculation Notification means for notifying the communication device of the number of bits that have been generated.

  According to still another aspect of the present invention, a communication system includes a communication device that performs data communication with a home device using a multi-carrier method using a communication line, and a home device. The communication device modulates the modulation method used when digitally modulating the subcarriers constituting the multicarrier while the data communication is online, and the home device is modulated online before starting the data communication. Setting means for setting the signal-to-noise ratio margin in data communication based on whether or not it has a function to change the system, and the set signal-to-noise ratio margin to the home device before starting data communication Notification means. The in-home device receives the signal to noise ratio margin from the communication device.

  According to still another aspect of the present invention, the signal-to-noise ratio margin setting method is executed in a communication device that performs data communication with a home device using a multi-carrier method using a communication line. The signal-to-noise ratio margin setting method has a function of changing the modulation method when the home device digitally modulates the subcarriers constituting the multicarrier while the data communication is online before starting the data communication. And a step of setting a signal-to-noise ratio margin in data communication based on the result of the determination.

  According to still another aspect of the present invention, the program controls a communication device that performs data communication with a home device using a multi-carrier method using a communication line. Before starting data communication, the program determines whether or not the in-home device has a function of changing the modulation scheme used when digitally modulating the subcarriers constituting the multicarrier while the data communication is online. The processor of the communication device is caused to execute a step and a step of setting a signal-to-noise ratio margin in data communication based on the determination result.

  According to the present invention, it is possible to reduce the occurrence of communication errors while utilizing the OLR function.

It is a figure for demonstrating schematic structure of a communication system. It is a figure for demonstrating the magnitude of the SNR margin notified to a household device by the procedure of an initialization. It is a figure for demonstrating the relationship between SNR measured in the procedure of initialization, and a SNR margin. It is a figure showing the outline of the procedure of initial setting. It is a functional block diagram which shows the structure of the collective apparatus and household device in a communication system. It is a functional block diagram which shows the structure of the input data process part and control part in an aggregation apparatus. It is a functional block diagram which shows the structure of the input data process part and control part in a household device. It is the sequence chart which showed the flow of the process in a communication system. It is a figure showing the data for a collective device to judge the presence or absence of the OLR function of a household device. It is the sequence chart which showed the flow of the process in a communication system in case a subscriber | terminal apparatus notifies an allocation bit number to an aggregation apparatus.

  Hereinafter, a communication system according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. In the following, data communication using the VDSL system will be described as an example.

<A. Overview>
FIG. 1 is a diagram for explaining a schematic configuration of the communication system 100. Referring to FIG. 1, a communication system 100 includes a collective device 1, a plurality of in-home devices 2a, 2b, 2c, a plurality of telephones 920a, 920b, 920c, a plurality of computers 930a, 930b, 930c, and an MDF 950. The server apparatus 970 is provided.

  The collective device 1 and the MDF 950 are installed in the MDF room 1004 of the collective housing 1000. The aggregation device 1 is connected to the MDF 950 so as to be communicable. The collective device 1 is connected to the Internet network 850 by an optical fiber 830. A server device 970 is communicably connected to the Internet network 850. The MDF 950 is connected to the telephone network 870.

  In-home device 2a, telephone 920a, and computer 930a are installed in room 1001 of apartment house 1000. The computer 930a is communicably connected to the in-home device 2a. The in-home device 2a and the telephone 920a are connected to the MDF 950 in the MDF room 1004 through the modular jack 910a by a metal cable 810a.

  In-home device 2b, telephone 920b, and computer 930b are installed in room 1002 of apartment house 1000. The computer 930b is communicably connected to the home device 2b. The in-home device 2b and the telephone 920b are connected to the MDF 950 via a modular jack 910b by a metal cable 810b.

  The in-home device 2c, the telephone 920c, and the computer 930c are installed in a room 1003 of the apartment house 1000. The computer 930c is communicably connected to the in-home device 2c. The in-home device 2c and the telephone 920c are connected to the MDF 950 via a modular jack 910c by a metal cable 810c.

  In the following, it is assumed that the in-home device 2a is a device having an OLR function. Further, it is assumed that the in-home devices 2b and 2c are devices that do not have the OLR function. That is, the collective device 1 can change the modulation method for digitally modulating the subcarriers constituting the multicarrier only in communication with the in-home device 2a while data communication (communication after initial setting) is online. To do. Examples of the modulation method include QPSK (quadrature phase shift keying), 16QAM (quadrature amplitude modulation), 64QAM, and the like. Hereinafter, a configuration in which the aggregation device 1 performs calculation of the number of allocated bits will be described.

  The server device 970 stores a plurality of data tables (FIG. 9) described later in advance. The configuration in which the aggregation device 1 uses the server device 970 will be described in “<F. Modification> (f2. Second Modification)”.

  In the following description, for convenience of description, when any one of the plurality of home devices 2a, 2b, and 2c is represented, it is referred to as “home device 2”. When any one of the plurality of telephones 920a, 920b, and 920c is represented, it is referred to as “telephone 920”. Further, when one of the plurality of computers 930a, 930b, and 930c is represented, it is referred to as “computer 930”. In addition, when any one of the plurality of metal cables 810a, 810b, and 810c is represented, it is referred to as “metal cable 810”. Further, when any one of the plurality of modular jacks 910a, 910b, 910c is represented, it is referred to as “modular jack 910”.

  In the following, for convenience of explanation, downlink (downward direction) communication from the collective device 1 to the in-home device 2 is also simply referred to as “downstream”. Further, uplink (upstream) communication from the in-home device 2 to the collective device 1 is also simply referred to as “upstream”.

<B. SNR margin>
(B1. Setting of SNR margin in initial setting procedure)
The SNR margin is a target margin set by the aggregation device 1. In the initial setting procedure (“12.3 Initialization Procedure” of Non-Patent Document 1 (ITU-T Recommendation G.993.2 (02/2006)) described above), the collective device 1 The SNR margin corresponding to the device 2 is notified. In the following, Non-Patent Document 1 (ITU-T Recommendation G.993.2 (02/2006)) is simply referred to as “ITU-T Recommendation G.993.2”.

  FIG. 2 is a diagram for explaining the magnitude of the SNR margin notified to the in-home device 2 in the initial setting procedure. Referring to FIG. 2, the aggregation device 1 can turn on the OLR function and turn off the OLR function.

  When the OLR function is turned on, the aggregation device 1 sets the SNR margin to be small when the in-home device 2 has the OLR function (indicated as “OLR compatible” in FIG. 2). Further, the collective device 1 sets a large SNR margin when the in-home device 2 does not have the OLR function (indicated as “OLR incompatible” in FIG. 2).

  That is, the collective device 1 reduces the SNR margin in communication with the in-home device 2a having the OLR function, and increases the SNR margin in communication with the in-home devices 2b and 2c not having the OLR function. For example, when the in-home device 2 has the OLR function, the collective device 1 sets the value V1 of the value V1 and the value V2 larger than the value V1 as the SNR margin, and the in-home device 2 performs the OLR. If the function is not provided, the value V2 is set as the SNR margin.

  When the OLR function is turned off, the collective device 1 sets a large SNR margin regardless of the presence / absence of the OLR function of the in-home device 2.

  As described above, when the collective device 1 has the OLR function turned on, the in-home device 2 has the OLR function in the initial setting procedure before starting the data communication (hereinafter also referred to as “main communication”). The SNR margin in training and data communication is set based on whether or not In the following description, it is assumed that the collective device 1 has the OLR function turned on.

  FIG. 3 is a diagram for explaining the relationship between the SNR and the SNR margin measured in the initial setting procedure. FIG. 3 is also a diagram for explaining the modulation method.

  FIG. 3A is a diagram showing a case where the aggregation device 1 sets a larger SNR margin. FIG. 3B is a diagram in which the aggregation device 1 sets the SNR margin to a small value. FIG. 3A is also a graph of the SNR margin notified to the in-home devices 2b and 2c. FIG. 3B is also a graph of the SNR margin notified to the in-home device 2a.

  Referring to FIGS. 3A and 3B, information on the amount corresponding to the value obtained by subtracting the hatched portion value (SNR margin) from the SNR value (measured value) in each subcarrier is shown in FIG. Can be sent.

  Specifically, the aggregation device 1 sets the distribution of the number of bits to be allocated to the subcarriers in the uplink using the SNR margin and the uplink SNR (actually measured value) in training, which is an initial setting procedure. The aggregation device 1 determines the uplink modulation scheme based on the distribution. Further, in the training, the aggregation device 1 sets the distribution of the number of bits to be allocated to the subcarriers in the downlink using the SNR margin and the downlink SNR (actually measured value). The aggregation device 1 determines a downlink modulation scheme based on the distribution.

  For example, in QPSK, 16QAM, and 64QAM, 2-bit, 4-bit, and 6-bit information can be transmitted, respectively. That is, the modulation scheme and the number of bits that can be transmitted in each modulation scheme are determined. For this reason, the aggregation device 1 selects, for example, one modulation scheme from the plurality of modulation schemes according to the set number of bits.

  If the value obtained by subtracting the value of the hatched portion from the SNR value in the subcarrier is large, the aggregation device 1 notifies the indoor device 2 of, for example, 64QAM as a modulation method before the training. On the other hand, if the value obtained by subtracting the hatched portion from the SNR value in the subcarrier is small, the aggregation device 1 notifies the in-home device 2 of, for example, QPSK as the modulation method before the training.

  In the above description, the case where the same SNR margin is applied to all subchannels has been described as an example. However, the present invention is not limited to this. Different SNR margins may be applied to each channel (in units of a plurality of subchannels).

(B2. SRA function and SOS function)
Next, as a supplementary explanation of the present embodiment, the SRA function and the SOS function used in the main communication after the initial setting procedure will be briefly described.

  As described above, the SRA function is a function that gently changes the communication speed when the noise change is small. More specifically, the SRA function is a function that optimizes the communication speed while maintaining the value of a preset target margin (SNR margin set in initial communication) with respect to the increase and decrease of noise that changes relatively slowly. is there. The SRA function operates using the downshift margin and the upshift margin as thresholds.

  When the actual SNR margin (the SNR margin that is actually secured during this communication) decreases due to the increase in noise level and the actual SNR margin falls below the downshift margin, the communication speed is reduced by the SRA function (specifically, the downshift SRA function). Lowering processing is performed. Thereafter, when the actual SNR margin increases due to a decrease in noise level and the actual SNR margin becomes equal to or greater than the upshift margin, processing for increasing the communication speed is performed by the SRA function (specifically, the upshift SRA function).

  As described above, the SOS function is a function of rapidly reducing the communication speed when the noise change is large. More specifically, the SOS function is a function that reduces the occurrence of communication errors by instantaneously lowering the communication speed to ensure an actual SNR margin for noise against sudden increases in noise. With the SOS function, even if a sudden increase in noise occurs, communication can be continued while avoiding link down. After the noise level is lowered, a process for restoring the optimum communication speed is performed by the SRA function (specifically, the upshift RA function).

<C. Initial setting procedure (initial communication)>
Next, details of the initial setting procedure will be described. The communication system 100 performs initial setting in accordance with “12.3 Initialization Procedure” of “ITU-T Recommendation G.993.2” described above.

  FIG. 4 shows an overview of the initial setting procedure. Referring to FIG. 4, the initialization procedure P5 includes a handshake phase P51, a channel discovery phase P52, a training phase P53, and a channel analysis and exchange phase P54. The communication system 100 executes a handshake phase P51, a channel discovery phase P52, a training phase P53, and a channel analysis and exchange phase P54 in this order.

  In the communication system 100, in each phase P51 to P54, each process described in “12.3 Initialization Procedure” of “ITU-T Recommendation G.993.2” is executed. The detailed description of each process will not be repeated here. In the following, description will be given mainly focusing on new processes other than the processes performed in the communication system 100.

  In phase P51 of the handshake, the aggregation device 1 acquires information (hereinafter also referred to as “capability information”) indicating whether or not it has the OLR function from the in-home device 2. For example, the collective device 1 may acquire capability information by inquiring the in-home device 2 as to whether or not the in-home device 2 has the OLR function. Alternatively, an arrangement may be made in advance in the communication system 100 so that capability information is sent from the home device 2 without making an inquiry.

  The aggregation device 1 selects different values as the SNR margin depending on whether the in-home device 2 has the OLR function or not. That is, the collective device 1 sets the SNR margin in the main communication based on whether or not the in-home device 2 has the OLR function in the initial setting procedure before starting the main communication.

  In the channel discovery phase P52, the aggregation device 1 notifies the corresponding in-home device 2 of the set SNR margin. In the training phase P53, the aggregation device 1 calculates the number of allocated bits in each subcarrier using the SNR margin and SNR for each of uplink and downlink communications. The aggregation device 1 determines an uplink modulation scheme and a downlink modulation scheme based on the calculation result. The aggregation device 1 receives the capability information again in the phase P54 of channel analysis and exchange. The reception of the capability information is processing according to “ITU-T Recommendation G.993.2”.

  Thus, the collective device 1 can acquire information on whether or not the in-home device 2 has the OLR function in the handshake phase P51. Therefore, the aggregation device 1 can set the SNR margin according to the presence / absence of the OLR function of the in-home device 2 before the channel discovery phase P52 and the training phase P53. Therefore, in the communication system 100, training and subsequent main communication can be performed using the SNR margin set based on the presence or absence of the OLR function of the in-home device 2.

  That is, in the configuration in which the setting of the SNR margin is determined after the channel analysis and exchange phase P54, the SNR margin cannot be set according to the presence / absence of the OLR function of the in-home device 2, but in the communication system 100, the in-home device The SNR margin can be set in accordance with the presence / absence of the 2 OLR function.

  Therefore, the collective device 1 can reduce the occurrence of communication errors while utilizing the OLR function in a communication system in which a home device having the OLR function and a home device not having the OLR function are mixedly included. More specifically, the collective device 1 can perform efficient data communication with the in-home device 2a having the OLR function by setting the SNR margin low, and the in-home devices 2b and 2c having no OLR function In the meantime, it is possible to prevent a situation where the SNR margin is set low even though the OLR function is not provided.

<D. Functional block diagram>
(D1. Communication system)
FIG. 5 is a functional block diagram showing configurations of the collective device 1 and the home device 2 in the communication system 100. Referring to FIG. 5, collective device 1 and in-home device 2 are connected via metal cable 810. Aggregation device 1 transmits a plurality of communication signals corresponding to a plurality of subcarriers to in-home device 2 which is a communication partner. The in-home device 2 transmits a plurality of communication signals corresponding to the plurality of subcarriers to the collective device 1 which is a communication partner.

  The aggregation device 1 includes a transmission unit 61, a reception unit 62, a storage unit 8A, a control unit 17A, an input data processing unit 10, and an output data processing unit 32. The transmission unit 61 includes a modulator (IFFT) 12, a parallel / serial (P / S) converter 14, a digital / analog converter (DAC) 16, a driver unit 20, and a hybrid circuit 22. The receiving unit 62 includes a hybrid circuit 22, a low noise amplifier 24, an analog / digital converter (ADC) 26, a serial / parallel (S / P) converter 28, and a demodulator (FFT) 30.

  The input data processing unit 10 performs various signal processing, which will be described later, on input data transmitted to a partner device (home device 2) that is a communication partner, and assigns the signal-processed input data to a plurality of subcarriers. Then, the input data processing unit 10 outputs the data of each subcarrier to the modulator 12.

  The modulator 12 digitally modulates the data of each subcarrier received from the input data processing unit 10 by inverse fast Fourier transform (IFFT). Then, the modulator 12 outputs the digital modulation signal to the parallel / serial converter 14.

  The parallel / serial converter 14 converts the parallel signal received from the modulator 12 into a serial signal and outputs the serial signal to the digital / analog converter 16.

  The digital / analog converter 16 converts the digital signal received from the parallel / serial converter 14 into an analog signal and outputs the analog signal to the driver unit 20.

  The driver unit 20 amplifies the analog signal received from the digital / analog converter 16 to a predetermined level and outputs the amplified signal to the hybrid circuit 22.

  The hybrid circuit 22 transmits the analog signal received from the driver unit 20 as a communication signal to the counterpart device (home device 2) via the metal cable 810. Further, the hybrid circuit 22 outputs an analog signal, which is a communication signal received from the counterpart device (home device 2) via the metal cable 810, to the low noise amplifier 24.

  The low noise amplifier 24 adjusts the analog signal received from the hybrid circuit 22 to a predetermined level, and then outputs the analog signal to the analog / digital converter 26.

  The analog / digital converter 26 converts the analog signal received from the low noise amplifier 24 into a digital signal and outputs the digital signal to the serial / parallel converter 28.

  The serial / parallel converter 28 converts the serial signal received from the analog / digital converter 26 into a parallel signal and outputs the parallel signal to the demodulator 30.

  The demodulator 30 digitally demodulates the data received from the serial / parallel converter 28 by fast Fourier transform (FFT). The demodulator 30 then outputs the digitally demodulated data for each subcarrier to the output data processing unit 32.

  The output data processing unit 32 restores the original data from the data for each subcarrier received from the demodulator 30 and outputs it to the outside. Further, the output data processing unit 32 outputs a part or all of the restored data to the control unit 17A as received data information.

  The control unit 17A controls each block in the communication device such as the input data processing unit 10, the modulator (IFFT) 12, the demodulator (FFT) 30, and the output data processing unit 32.

  The in-home device 2 includes a transmission unit 61, a reception unit 62, a storage unit 8B, a control unit 17B, an input data processing unit 10, and an output data processing unit 32. The transmission unit 61 includes a modulator (IFFT) 12, a parallel / serial (P / S) converter 14, a digital / analog converter (DAC) 16, a driver unit 20, and a hybrid circuit 22. The receiving unit 62 includes a hybrid circuit 22, a low noise amplifier 24, an analog / digital converter (ADC) 26, a serial / parallel (S / P) converter 28, and a demodulator (FFT) 30.

  In the in-home device 2, the processing in the control unit 17B is different from the processing in the control unit 17A of the collective device 1. Further, the various programs and data stored in the storage unit 8B are different from the various programs and data stored in the storage unit 8A of the collective device 1. Since the other configuration of the in-home device 2 is the same as that of the collective device 1, it will not be described repeatedly here.

  Note that the output data processing unit 32 of the in-home device 2 outputs part or all of the restored data to the control unit 17B as received data information. The control unit 17B controls each block in the communication device such as the input data processing unit 10, the modulator (IFFT) 12, the demodulator (FFT) 30, and the output data processing unit 32.

(D2. Main part of the collective device 1)
FIG. 6 is a functional block diagram illustrating configurations of the input data processing unit 10 and the control unit 17A in the collective device 1.

  Referring to FIG. 6, input data processing unit 10 includes a logical channel generation unit 41, error correction coding units 42 to 44, interleave processing units 45 to 47, and a data allocation processing unit 48. Control unit 17A includes subcarrier allocation / communication speed determination unit 51A, modulation scheme determination / change unit 52A, SNR measurement unit 53A, error rate measurement unit 54A, and parameter setting unit 55A.

  The logical channel generation unit 41 receives data from the outside, generates data of a plurality of logical channels (CH1 to CH3 in FIG. 6) from the input data, and outputs the data to the error correction encoding units 42 to 44.

  The error correction encoding units 42 to 44 perform, for example, CRC (Cyclic Redundancy Check) processing and FEC (Forward Error Correction) processing on the data of each logical channel received from the logical channel generation unit 41, and then to the interleave processing units 45 to 47. Output.

  Interleaving processing units 45 to 47 perform interleaving processing on the data of each logical channel received from error correction coding units 42 to 44 based on the interleaving depth set for each logical channel by parameter setting unit 55A. The data is output to the data allocation processing unit 48.

  The data allocation processing unit 48 rearranges the data of each logical channel received from the interleave processing units 45 to 47 based on the correspondence relationship between the logical channel and the subcarrier represented by the allocation table described later, and outputs the data to the modulator 12. .

The operation of each block in the control unit 17A will be described later.
(D3. Main part of in-home device 2)
FIG. 7 is a functional block diagram showing the configuration of the input data processing unit 10 and the control unit 17B in the home device 2.

  Control unit 17B includes a subcarrier allocation / communication speed determination unit 51B, a modulation scheme determination unit 52B, an SNR measurement unit 53B, an error rate measurement unit 54B, and a parameter setting unit 55B. The parameter setting unit 55B sets the interleave depth for each logical channel.

  Note that the configuration and basic operation of the input data processing unit 10 of the in-home device 2 are the same as those of the collective device 1, and thus detailed description thereof will not be repeated here.

The operation of each block in the control unit 17B will be described later.
(D4. Operations of the collective device 1 and the home device 2)
Next, operations of the collective device 1 and the in-home device 2 will be described in detail based on FIG. 6 and FIG.

  In a state where the collective device 1 and the in-home device 2 are communicating, the collective device 1 monitors the reception quality of the communication signal between the collective device 1 and the in-home device 2. More specifically, the error rate measurement unit 54A of the aggregation device 1 determines the error rate of the communication signal in the upstream communication from the in-home device 2 to the aggregation device 1 based on the received data information received from the output data processing unit 32. calculate. Based on the received data information received from the output data processing unit 32, the error rate measurement unit 54B of the in-home device 2 calculates an error rate of a communication signal in downlink communication from the aggregation device 1 to the in-home device 2.

  The control unit 17B of the in-home device 2 controls the input data processing unit 10 and the like, includes the calculation result of the error rate in the communication signal, and transmits it to the aggregation device 1. The error rate measurement unit 54A of the aggregation device 1 extracts the error rate of the downlink communication signal from the received data information received from the output data processing unit 32.

  The aggregation device 1 performs control to disconnect the uplink and downlink lines when the error rate of the downlink communication signal or the error rate of the uplink communication signal is equal to or greater than a predetermined value.

  Next, training is started in the communication system 100. More specifically, when the uplink and downlink lines are disconnected, the collective device 1 and the in-home device 2 perform an initialization procedure (hereinafter also referred to as “initialization process”). For example, the control units 17A and 17B control the modulator 12, the demodulator 30 and the like to transmit and receive a non-modulated signal, whereby an AGC (Auto Gain Control) circuit included in each driver unit 20 and low noise amplifier 24 is obtained. Set the gain.

  When the initialization process ends, the parameter setting unit 55A of the aggregation device 1 sets the SNR margin, the data rate, and the interleave depth. For example, the storage unit 8A stores a set value table in which an SNR margin, a data rate, and an interleave depth are defined. The parameter setting unit 55A selects one of the plurality of setting value tables and sets the SNR margin, the data rate, and the interleave depth.

  As an example, the control unit 17A of the aggregation device transmits a request signal for inquiring whether or not it has the OLR function to the control unit 17B of the in-home device 2. The control unit 17A receives a signal (capability information) indicating whether or not it has the OLR function from the control unit 17B of the in-home device 2 as a response signal of the request signal. The parameter setting unit 55A sets the SNR margin based on the capability information.

  The collective device 1 transmits the generated downlink setting value table to the in-home device 2. More specifically, the parameter setting unit 55A outputs the generated downlink setting value table to the input data processing unit 10. The downlink setting value table is subjected to signal processing such as error correction coding and assignment to subcarriers in the input data processing unit 10, and includes a modulator 12, a P / S converter 14, a digital / analog converter 16, It is transmitted to the in-home device 2 via the driver unit 20 and the hybrid circuit 22. In this aspect, the set SNR margin is notified to the in-home device 2 by the transmission unit 61.

  Further, the collective device 1 transmits, for example, a PN (Pseudo Noise) series signal (hereinafter also referred to as a test signal) to the in-home device 2 as a communication signal. The test signal is transmitted to the in-home device 2 through the input data processing unit 10, the modulator 12, the P / S converter 14, the digital / analog converter 16, the driver unit 20, and the hybrid circuit 22 as in the set value table. Is done.

  The in-home device 2 measures the SNR of the test signal received from the collective device 1. More specifically, in the in-home device 2, the demodulator 30 receives the data corresponding to the test signal from the serial / parallel converter 28, digitally demodulates it, and outputs the constellation to the control unit 17B. The SNR measurement unit 53B measures the SNR of the test signal based on the constellation received from the demodulator 30. Note that “constellation” means symbol point arrangement on an IQ coordinate axis plane composed of an in-phase (I-phase) component and a quadrature (Q-phase) component of a modulation signal.

  The in-home device 2 determines one or a plurality of subcarriers to be allocated to a plurality of logical channels based on the SNR measurement result of the test signal and the downlink setting value table received from the aggregation device 1, and Communication speeds of a plurality of communication signals transmitted from the device 1 are determined.

  The subcarrier allocation / communication speed determination unit 51B extracts the downlink setting value table transmitted by the aggregation device 1 from the received data information received from the output data processing unit 32. Subcarrier allocation / communication speed determination unit 51B then assigns subcarriers to be allocated to a plurality of logical channels based on the SNR measurement result of the test signal and the SNR margin and data rate indicated by the extracted downlink setting value table. The number of bits to be determined and assigned to each subcarrier, that is, the communication speed of each communication signal is determined. The subcarrier allocation / communication speed determination unit 51B generates a downlink allocation table indicating the subcarriers allocated to each of the plurality of logical channels and the number of bits allocated to each subcarrier, and the logical channel generation unit 41 and the modulation scheme determination unit To 52B.

  The downlink allocation table is transmitted to the aggregation device 1 via the input data processing unit 10, the modulator 12, the P / S converter 14, the digital / analog converter 16, the driver unit 20, and the hybrid circuit 22.

  The subcarrier allocation / communication speed determination units 51A and 51B can perform communication in which the communication signal can satisfy a predetermined reception quality under the SNR measurement result of the test signal, that is, the SNR condition of the communication signal measured by the SNR measurement units 53A and 53B. A communication speed lower than the speed is determined as the communication speed of the communication signal from the communication partner. That is, the subcarrier allocation / communication speed determination units 51A and 51B communicate the communication speed at which the error rate of the communication signal is less than a predetermined value under the SNR condition that is further deteriorated by the SNR margin from the measured SNR of the communication signal. It is determined as the communication speed of the communication signal from the other party.

  Aggregation apparatus 1 determines, for example, a plurality of communication signal modulation schemes based on communication speeds of a plurality of communication signals corresponding to a plurality of subcarriers, as indicated by a downlink allocation table received from in-home apparatus 2. To do. More specifically, the modulation scheme determining / changing unit 52A extracts the downlink allocation table transmitted by the home device 2 from the received data information received from the output data processing unit 32. Then, modulation scheme determining / changing section 52A determines the modulation schemes for a plurality of communication signals corresponding to the plurality of subcarriers based on the extracted downlink allocation table, and sends the determined modulation schemes to modulator 12. Notice. Modulator 12 modulates the data of each subcarrier by the modulation method indicated by the notification content from control unit 17A.

  The modulation scheme determination unit 52B of the in-home device 2 recognizes the modulation scheme of the communication signal transmitted from the aggregation device 1 based on the downlink allocation table received from the subcarrier allocation / communication speed determination unit 51B, and demodulates the demodulator 30. To notify. Demodulator 30 demodulates the communication signal of each subcarrier using the modulation method indicated by the notification content from control unit 17B.

  The aggregation device 1 transmits the generated uplink setting value table to the in-home device 2. Also, parameter setting unit 55A of aggregation device 1 outputs the generated uplink setting value table to subcarrier allocation / communication speed determination unit 51A. The in-home device 2 transmits a test signal to the aggregation device 1.

  The aggregation device 1 measures the SNR of the test signal received from the home device 2. The aggregation device 1 determines one or a plurality of subcarriers to be allocated to each of a plurality of logical channels based on the SNR measurement result of the test signal and the uplink setting value table generated by itself. The collective device 1 also determines the communication speeds of the plurality of communication signals transmitted from the in-home device 2. For example, the aggregation device 1 generates an uplink allocation table that indicates the correspondence between the plurality of logical channels, the plurality of subcarriers, and the number of bits allocated to each subcarrier used by the in-home device 2 for transmission of communication signals. Transmit to device 2.

  The in-home device 2 determines, for example, a plurality of communication signal modulation schemes based on the communication speeds of the plurality of communication signals corresponding to the plurality of subcarriers represented by the uplink allocation table received from the aggregation device 1. To do. The in-home device 2 modulates the data of each subcarrier by the modulation method indicated by the notification content from the control unit 17B.

  Based on the uplink allocation table received from subcarrier allocation / communication speed determination unit 51A, modulation scheme determination / change unit 52A recognizes the modulation scheme of the communication signal transmitted from in-home device 2 and notifies demodulator 30. To do. Demodulator 30 demodulates the communication signal of each subcarrier by the modulation method represented by the notification content from control unit 17A.

  Also, the modulation scheme determining / changing section 52A changes the modulation scheme used when digitally modulating the subcarriers constituting the multicarrier in accordance with the measured SNR in this communication (data communication is online). When the SNR measured in this communication decreases, the modulation scheme determination / change unit 52A changes to a modulation scheme that transmits information with a smaller number of bits. For example, the modulation scheme determination / change unit 52A changes the modulation scheme from 64QAM to 16QAM. In addition, when the SNR measured in this communication increases, the modulation scheme determination / change unit 52A changes to a modulation scheme that transmits information of a larger number of bits. For example, the modulation scheme determination / change unit 52A changes the modulation scheme from 16QAM to 64QAM.

<E. Control structure>
FIG. 8 is a sequence chart showing the flow of processing in the communication system 100. FIG. 8 is a sequence chart focusing on processing between the collective device 1 and one in-home device 2.

  Referring to FIG. 8, in step S <b> 2, home device 2 notifies capability information to aggregation device 1. In step S4, the aggregation device 1 sets an SNR margin using the capability information. That is, the collective device 1 sets the SNR margin based on whether the in-home device 2 has the OLR function.

  In step S6, the collective device 1 notifies the in-home device 2 of the set SNR margin. In step S8, the in-home device 2 measures the downlink SNR. In step S10, the in-home device 2 notifies the aggregation device 1 of the measured SNR.

  In step S12, the collective device 1 calculates the number of allocated bits based on the SNR received from the in-home device 2 and the SNR margin set in step S4. In step S14, the aggregation device 1 determines a downlink modulation scheme based on the calculated allocation bits. In step S16, the collective device 1 notifies the in-home device 2 of the determined downlink modulation scheme.

  In step S18, the aggregation device 1 measures the uplink SNR. In step S20, the aggregation device 1 calculates the allocated bits based on the SNR measured in step S18 and the SNR margin set in step S4. In step S22, the aggregation device 1 determines an uplink modulation scheme based on the calculated number of allocated bits. In step S24, the collective device 1 notifies the in-home device 2 of the determined uplink modulation scheme.

  In step S26, the in-home apparatus 2 notifies the capability information again. In step S28, the collective device 1 and the in-home device 2 start this communication.

  As described above, the capability information transmission processing in step S26 is processing in accordance with “12.3 Initialization Procedure” of “ITU-T Recommendation G.993.2”. On the other hand, in the communication system 100, capability information has already been exchanged in the handshake phase P51. Therefore, in the communication system 100, it is not always necessary to exchange capability information in the channel analysis and exchange phase P54. However, in accordance with the current “ITU-T Recommendation G.993.2”, it is necessary to exchange capability information in the phase P54 of channel analysis and exchange.

  The order of steps S8, S10, S12, S14, S16, S18, S20, S22, and S24 included in the training phase P53 is not limited to the order shown in FIG. For example, steps S18, S20, and S22 may be performed before steps S12 and S14. Further, instead of notifying the in-home device 2 separately of the downlink modulation scheme and the uplink modulation scheme as shown in steps S16 and S24, the aggregation device 1 includes these modulation schemes in one data at the same time. The in-home device 2 may be notified.

<F. Modification>
(F1. First modification)
In the above description, the configuration in which the collective device 1 receives capability information from the in-home device 2 in the initial setting procedure has been described as an example. However, the present invention is not limited to this.

  In the handshake phase P51, the collective device 1 may be configured to acquire the identification symbol of the in-home device 2 from the in-home device 2 and determine whether the indoor device 2 has the OLR function based on the identification symbol. . Alternatively, the collective device 1 is configured to acquire the model name of the home device 2 from the home device 2 in the phase P51 of the handshake and to determine whether the home device 2 has the OLR function based on the model name. Also good. Alternatively, the collective device 1 is configured to acquire the firmware version information of the in-home device 2 from the in-home device 2 in the handshake phase P51 and determine the presence or absence of the OLR function of the in-home device 2 based on the version information. May be. Hereinafter, these three configurations will be described.

  FIG. 9 is a diagram showing data for the collective device 1 to determine whether the home device 2 has the OLR function. FIG. 9A is a diagram showing a data table D101 used when the presence / absence of the OLR function of the in-home device 2 is determined based on the identification symbol of the in-home device 2. FIG. 9B is a diagram showing a data table D102 used when determining the presence or absence of the OLR function of the home device 2 based on the model name of the home device 2. FIG. 9C is a diagram illustrating a data table D103 that is used when determining the presence or absence of the OLR function of the home device 2 based on the firmware version information of the home device 2.

  These data tables D101, D102, and D103 are stored in advance in the storage unit 8A of the collective device 1, for example, when the collective device 1 is shipped. The aggregation device 1 is preferably configured so that the data tables D101, D102, D103 are updated.

  Below, the structure which uses the data table D101 first is demonstrated. Next, a configuration using the data table D102 will be described. Finally, a configuration using the data table D103 will be described.

  Referring to FIG. 9A, in data table D101, regardless of whether or not communication system 100 is configured, for example, an identification symbol of a commercially available home device corresponds to information indicating the presence or absence of the OLR function. It is described with a name. Examples of the identification symbol include a MAC address.

  The collective device 1 acquires the identification symbol of the home device 2 from the home device 2 in phase P51 of the handshake. The aggregation device 1 refers to the data table D101 to determine whether the in-home device 2 has the OLR function. The aggregation device 1 sets an SNR margin based on the determination result, and notifies the in-home device 2 of the SNR margin in the channel discovery phase P52.

  As described above, the storage unit 8A stores the data table D101 that indicates whether each of the plurality of in-home devices has the OLR function. The parameter setting unit 55A determines whether the in-home device 2 has the OLR function based on the data table D101 and the identification information of the in-home device 2 transmitted from the in-home device 2 in the phase P51 of the handshake before training. Determine whether.

  Referring to FIG. 9B, in data table D102, regardless of whether communication system 100 is configured, for example, the model name of a commercially available home device corresponds to information indicating the presence or absence of the OLR function. It is described with a name. The collective device 1 acquires the model name of the home device 2 from the home device 2 in the handshake phase P51. The aggregation device 1 refers to the data table D102 to determine whether the in-home device 2 has the OLR function. The aggregation device 1 sets an SNR margin based on the determination result, and notifies the in-home device 2 of the SNR margin in the channel discovery phase P52.

  As described above, the storage unit 8A stores the data table D102 that represents whether each of the plurality of in-home devices has the OLR function. Based on the data table D102 and the model name of the home device 2 transmitted from the home device 2 in the phase P51 of the handshake before training, the parameter setting unit 55A determines whether the home device 2 has the OLR function. Judge whether or not.

  Referring to FIG. 9C, in the data table D103, regardless of whether or not the communication system 100 is configured, for example, firmware version information of a commercially available home device is information indicating the presence or absence of the OLR function. It is described in association with. The collective device 1 acquires the firmware version information of the home device 2 from the home device 2 in the phase P51 of the handshake. The aggregation device 1 refers to the data table D103 to determine whether the in-home device 2 has the OLR function. The aggregation device 1 sets an SNR margin based on the determination result, and notifies the in-home device 2 of the SNR margin in the channel discovery phase P52.

  As described above, the storage unit 8A stores the data table D103 that indicates whether each of the plurality of in-home devices has the OLR function. Based on the data table D103 and the firmware version information of the home device 2 transmitted from the home device 2 in the phase P51 of the handshake before training, the parameter setting unit 55A has the OLR function. Judge whether or not.

  As described based on FIG. 9, the storage unit 8A of the collective device 1 stores data (data table) indicating whether each of the plurality of in-home devices has the OLR function. The parameter setting unit 55A determines whether or not the in-home device has the OLR function based on the data and the information transmitted from the in-home device 2 in the phase P51 of the handshake before training.

  Note that all the three data tables D101, D102, and D103 need not be stored in the storage unit 8A. Depending on whether the collective device 1 is configured to determine the presence or absence of the OLR function of the in-home device 2 using the identification information, the model name, and the firmware version information, a corresponding data table is stored in the storage unit 8A. That's fine.

  Further, the collective device 1 may determine the presence / absence of the OLR function of the home device 2 using two or more data tables among the three data tables D101, D102, and D103. That is, the collective device 1 may determine the presence / absence of the OLR function of the home device 2 from the home device 2 based on two or more pieces of information among the identification information, the model name, and the firmware version information. .

(F2. Second modification)
The collective device 1 may acquire the data tables D101, D102, and D103 from the connected server device 970 that is communicably connected to the collective device 1 via the Internet network 850. The acquisition timing is not particularly limited.

  For example, the collective device 1 may acquire the data tables D101, D102, and D103 from the server device 970 at a stage before the initial setting procedure. Alternatively, the aggregation device 1 acquires the identification information, model name, and / or firmware version information in the handshake phase P51 and before the channel discovery phase P52 (specifically, the handshake In the phase P51), the data tables D101, D102, D103 may be acquired from the server device 970.

(F3. Third modification)
In the above, the SNR measured by the home device 2 is notified to the aggregation device 1 (step S10 in FIG. 8). In this case, the aggregation device 1 calculates the number of allocated bits based on the SNR. However, the present invention is not limited to this.

  The home device 2 may be configured to calculate the number of allocated bits using the SNR measured by the home device 2 and the SNR margin notified from the aggregation device 1 and to notify the aggregation device 1 of the allocated bit number. Good. Alternatively, the in-home device 2 can be configured to determine the modulation method from the number of assigned bits and notify the aggregation device 1 of the determined modulation method.

  FIG. 10 is a sequence chart showing the flow of processing in the communication system 100 when the in-home device 2 notifies the aggregation device 1 of the number of allocated bits. FIG. 10 is a sequence chart focusing on the processing between the collective device 1 and one in-home device 2 as in FIG.

  Referring to FIG. 10, the process shown in FIG. 10 is different from the process shown in FIG. 8 in that step S102 and step S104 are provided instead of step S12 and step S10 in FIG. The other steps in FIG. 10 are the same as the steps denoted by the same numbers in FIG. 8, and thus description thereof will not be repeated here.

  The in-home device 2 calculates the number of allocated bits based on the measured downlink SNR in step S102 after step S8 and the SNR margin notified from the aggregation device 1 in step S6. In step S104, the in-home device 2 notifies the aggregation device 1 of information on the calculated number of allocated bits. In this case, the aggregation device 1 determines a downlink modulation scheme using the information on the number of allocated bits in step S14.

  In this case, it can be said that the in-home device 2 has the following configuration. That is, the reception unit 62 of the in-home device 2 sets the book set by the collective device 1 based on whether or not the in-home device 2 has the OLR function before starting the main communication with the collective device 1. An SNR margin in communication is received from the aggregation device 1. The SNR measurement unit 53B measures the SNR in the downlink from the collective device 1 to the in-home device 2 in the training for confirming the state of the communication line before performing this communication. In the training, the subcarrier allocation / communication speed determination unit 51B calculates the number of bits allocated to the subcarrier in the downlink using the SNR margin and the measured SNR. The transmission unit 61 of the household device 2 notifies the aggregation device 1 of the calculated number of bits.

  Even with a communication system using the home device 2 having such a configuration, it is possible to reduce the occurrence of communication errors while utilizing the OLR function.

(F4. Fourth modification)
In the above embodiment, the VDSL system has been described as an example of the xDSL communication, but the present invention can also be applied to the ADSL system.

(F5. Fifth modification)
In the above description, the configuration in which the margin setting is changed depending on the presence or absence of the OLR function has been described as an example. However, the configuration is not limited thereto. For example, the SNR margin setting is changed depending on whether the in-home equipment (CPE) is a VDSL2 modem (corresponding to “ITU-T Recommendation G.993.2”) or a VDSL1 modem (corresponding to “ITU-T Recommendation G.993.1”). May be.

  Furthermore, if each of the functions that the OLR function and the VDSL2 modem have and that the VDSL1 modem does not have is called a “specific function”, the collective device 1 “uses a communication line and uses a multicarrier method. It can be said that the configuration includes a parameter setting unit that sets an SNR margin in data communication based on whether or not the home device 2 has a specific function before starting data communication with the home device. In addition, as a specific function, it is not limited to what was mentioned above.

  The embodiment disclosed this time is an exemplification, and the present invention is not limited to the above contents. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Aggregation apparatus, 2, 2a, 2b, 2c Home apparatus, 8A, 8B Storage part, 10 Input data processing part, 12 Modulator, 14 Parallel / serial converter, 16 Digital / analog converter, 17A, 17B Control part, 20 Driver section, 22 Hybrid circuit, 24 Low noise amplifier, 26 Analog / digital converter, 28 Serial / parallel converter, 30 Demodulator, 32 Output data processing section, 41 Logical channel generation section, 42-44 Error correction coding , 45-47 interleave processing unit, 48 data allocation processing unit, 51A, 51B subcarrier allocation / communication speed determination unit, 52A modulation scheme determination / change unit, 52B modulation scheme determination unit, 53A, 53B SNR measurement unit, 54A, 54B error rate measurement unit, 55A, 55B parameter setting unit, 61 transmission unit, 62 Receiver, 100 Communication system, 810, 810a, 810b, 810c Metal cable, 830 Optical fiber, 850 Internet network, 870 Telephone network, 910, 910a, 910b, 910c Modular jack, 920, 920a, 920b, 920c Telephone, 930, 930a, 930b, 930c Computer, 970 server device, 1000 apartment house, 1001, 1002, 1003 room, 1004 MDF room, D101, D102, D103 data table.

Claims (16)

A communication device that uses a communication line to perform data communication with an in-home device using a multi-carrier method,
Changing means for changing the modulation scheme when digitally modulating subcarriers constituting a multicarrier while the data communication is online;
Setting means for setting a signal-to-noise ratio margin in the data communication based on whether the in-home device has a function of changing the modulation scheme in the online state before starting the data communication; A communication device comprising: The setting means determines whether or not the in-home device has the function before starting the training for checking the state of the communication line,
The communication device
The communication device according to claim 1, further comprising notification means for notifying the in-home device of the set signal-to-noise ratio margin before starting the training. Further comprising receiving means for receiving information indicating whether or not the in-home device has the function from the in-home device in the handshake before the training,
The communication device according to claim 2, wherein the setting unit determines whether or not the in-home device has the function based on the information. A storage means for storing data indicating whether each of the plurality of in-home devices has the function;
The setting means determines whether or not the in-home device has the function based on the data and information transmitted from the in-home device in a handshake before the training. The communication apparatus as described in.   The communication device according to claim 4, wherein the data is acquired from a communication device that is communicably connected to the communication device, and is stored in the storage device. The information includes identification information of the home device,
The communication device according to claim 4, wherein the setting unit determines whether the in-home device has the function using the identification information. The information includes information representing a model name of the home device,
The communication device according to claim 4, wherein the setting unit determines whether or not the in-home device has the function using information representing the model name. The information includes version information of firmware installed in the home device,
The communication device according to claim 4, wherein the setting unit determines whether the in-home device has the function using the version information.   The communication apparatus according to any one of claims 2 to 8, further comprising a determining unit that determines the modulation scheme using the set signal-to-noise ratio margin before starting the data communication.   The determining means uses the set signal-to-noise ratio margin in the training and the signal-to-noise ratio measured by the in-home device in the down-communication from the communication device to the in-home device, The communication apparatus according to claim 9, wherein the modulation method in communication is determined.   In the training, the determining means uses the set signal-to-noise ratio margin and the signal-to-noise ratio measured by the communication device in the uplink communication from the in-home device to the communication device. The communication device according to claim 9 or 10, wherein the modulation method in communication is determined. The setting means includes
In the case of having the function, the first value of the first value and the second value larger than the first value is set as the signal to noise ratio margin,
The communication apparatus according to any one of claims 1 to 11, wherein when the function is not provided, the second value is set as the signal-to-noise ratio margin. A home device that performs data communication with a communication device using a communication line,
Before starting the data communication, based on whether or not the in-house device has a function of changing a modulation method when digitally modulating subcarriers constituting a multicarrier while the data communication is online. Receiving means for receiving a signal-to-noise ratio margin in the data communication set by the communication device from the communication device;
In the training for checking the state of the communication line before performing the data communication, measuring means for measuring a signal-to-noise ratio in downlink communication from the communication device to the in-home device;
In the training, using the signal-to-noise ratio margin and the measured signal-to-noise ratio, calculation means for calculating the number of bits allocated to subcarriers in the downlink communication;
In-home device comprising notification means for notifying the communication device of the calculated number of bits. A communication device that performs data communication with a home device using a multi-carrier method using a communication line, and a communication system including the home device,
The communication device
Changing means for changing the modulation scheme when digitally modulating subcarriers constituting a multicarrier while the data communication is online;
Setting means for setting a signal-to-noise ratio margin in the data communication based on whether the in-home device has a function of changing the modulation scheme in the online state before starting the data communication; ,
Notification means for notifying the in-home device of the set signal-to-noise ratio margin before starting the data communication,
The communication device in which the in-home device receives the signal-to-noise ratio margin from the communication device. A method for setting a signal-to-noise ratio margin in a communication device that performs data communication with an in-home device using a multi-carrier method using a communication line,
Before starting the data communication, it is determined whether or not the in-home device has a function of changing the modulation scheme used when digitally modulating the subcarriers constituting the multicarrier while the data communication is online. Steps,
Setting a signal-to-noise ratio margin in the data communication based on the result of the determination. A program for controlling a communication device that performs data communication with an in-home device using a multi-carrier method using a communication line,
Before starting the data communication, it is determined whether or not the in-home device has a function of changing the modulation scheme used when digitally modulating the subcarriers constituting the multicarrier while the data communication is online. Steps,
A program for causing a processor of the communication device to execute a step of setting a signal-to-noise ratio margin in the data communication based on the result of the determination.

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