JP2006115326A - Communication system, communicating method and communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system, a communicating method and a communication apparatus which can suppress interference caused by crosstalk to another communication systems that provides a service by using an adjacent telephone line. <P>SOLUTION: A storing part 8 stores transmission power patterns obtained by associating a frequency band in which interference to an adjacent telephone line occurs with transmission power of each frequency band. A transmission power control part 6 receives setting from the outside, reads a transmission power pattern corresponding to the setting from the storing part 8 and gives the transmission power pattern to an encoder 10. The encoder 10 controls the transmission power of each subcarrier propagating in the telephone line so as to follow the transmission power pattern and subsequently encodes input data. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication system, a communication method, and a communication apparatus, and more particularly to a communication system, a communication method, and a communication apparatus that perform data communication via a telephone line.

  In VDSL (Very High-bit Digital Subscriber Line), which performs high-speed data communication using an existing telephone line, several tens of Mbps between the station-side device and the terminal-side device. High speed communication can be realized.

  As shown in Non-Patent Document 1, the ITU-T (ITU-Telecommunication standardization sector), which is a telecommunications standardization department of the ITU (International Telecommunication Union), is “G.993.1” related to the VDSL standard. Is recommended.

  In VDSL, a wide frequency band up to 12 MHz is used in order to realize high-speed communication in the upstream (transmission viewed from the subscriber side) and downstream (reception viewed from the subscriber side) direction. Since the signal in the high frequency band has a large power attenuation, VDSL is mainly targeted for a relatively short distance of about 500 m or less in a building or an apartment house.

  In other words, after terminating optical communication using FTTB (Fiber To The Building) optical fiber, the telephone line in the building is used between the VDSL station-side device and each VDSL terminal-side device placed in the building. Thus, a service form for performing data communication is assumed.

  By the way, as shown in Non-Patent Document 2, there is HomePNA (Home Phone line Networking Alliance) as a method for performing data communication using a telephone line at home, and this is a communication service that is converted to a telephone line in a building. Is provided.

  Further, as shown in Non-Patent Documents 3 to 6, an ADSL (Asymmetric DSL) that connects a station-side device installed in a telephone base station and a terminal-side device in a building or apartment house using a telephone line. Communication services using asymmetric digital subscriber lines) are also provided.

As described above, communication services using a plurality of different systems such as VDSL, HomePNA, ADSL, and other unique systems are provided via telephone lines.
"Very high speed digital subscriber line (VDSL)", ITU-T recommendation G.993.1 "Telephone line network transceiver", ITU-T recommendation G.989.1 "Asymmetric digital subscriber line (ADSL) transceiver", ITU-T recommendation G.992.1 "Splitterless asymmetric digital subscriber line (ADSL) transceiver", ITU-T recommendation G.992.2 "Asymmetric digital subscriber line (ADSL) transceiver (ADSL2)", ITU-T recommendation G.992.3 "Asymmetric Digital Subscriber Line (ADSL) Transceiver Band Extension (ADSL2plus)", ITU-T Recommendation G.992.5

  However, a general telephone line is accommodated in a telephone cable in which a plurality of lines are bundled. Therefore, crosstalk due to electromagnetic coupling occurs between two adjacent telephone lines.

  Therefore, VDSL using a frequency band up to 12 MHz and HomePNA using a frequency band from 4 MHz to 11.5 MHz overlap with each other, and interference due to crosstalk occurs.

  FIG. 13 is a conceptual diagram when the services of VDSL and HomePNA are provided via adjacent telephone lines.

  Referring to FIG. 13, there is a concern that the VDSL signal propagating through the adjacent telephone line leaks into the HomePNA signal, and the HomePNA communication speed is lowered due to the noise.

  Also, VDSL using a frequency band of 138 kHz or more and ADSL using a frequency band from 25 kHz to 3.75 MHz at the maximum overlap with each other, and interference due to crosstalk occurs.

  FIG. 14 is a conceptual diagram in the case where services of VDSL and ADSL are provided through adjacent telephone lines in a building.

  Referring to FIG. 14, there is a concern that the VDSL signal propagating on the adjacent telephone line in the building leaks into the ADSL signal, and the ADSL communication speed is lowered due to the noise.

  Accordingly, the present invention has been made to solve such a problem, and its purpose is to suppress interference caused by crosstalk with respect to other communication systems that provide services using adjacent telephone lines. A communication system, a communication method, and a communication device that can be used.

  According to the present invention, the communication system includes a first communication device and a second communication device that performs data communication with the first communication device via a telephone line. In response to an external command, the first communication device determines transmission power in a predetermined frequency band that causes interference with an adjacent telephone line selected from among the frequency bands used by the first communication device for transmission. To the level of. In response to an external command, the second communication device determines transmission power in a predetermined frequency band that causes interference with an adjacent telephone line selected from among the frequency bands used for transmission by the second communication device. To the level of.

  Preferably, the first communication device suppresses transmission power in a predetermined frequency band selected from frequency bands used for transmission by the second communication device to a predetermined level in response to a command from the outside. The transmission power suppression command is transmitted to the second communication device, and the second communication device receives the transmission power suppression command from the first communication device and suppresses the transmission power of the predetermined frequency band to a predetermined level. .

  Preferably, the first communication device and / or the second communication device pauses transmission with zero transmission power in a predetermined frequency band.

  Preferably, the first communication device and the second communication device perform data communication using a plurality of subcarriers having different frequencies, and the first communication device and / or the second communication device includes a plurality of subcarriers. The transmission power of one or more subcarriers corresponding to a predetermined frequency band selected from the subcarriers is suppressed to a predetermined level.

  Preferably, the first communication device or / and the second communication device suppress transmission power to a predetermined level for each of a plurality of bands constituting the frequency band.

  According to the present invention, there is also provided a communication method for performing data communication between a first communication device and a second communication device via a telephone line, wherein the first communication is performed in response to an instruction from the outside. A step of suppressing the transmission power of a predetermined frequency band in which interference to an adjacent telephone line selected from the frequency band used for transmission by the apparatus to a predetermined level, and a second according to an instruction from the outside, And suppressing the transmission power of a predetermined frequency band in which interference with an adjacent telephone line selected from the frequency band used for transmission by the communication apparatus occurs to a predetermined level.

  Preferably, a transmission power suppression command for suppressing transmission power in a predetermined frequency band selected from among frequency bands used for transmission by the second communication device to a predetermined level in response to a command from the outside. In response to the step of transmitting from the first communication device to the second communication device and the transmission power suppression command transmitted from the first communication device, the second communication device sets the transmission power of the predetermined frequency band to a predetermined level. And further comprising the step of suppressing.

  Preferably, the method further includes a step in which the first communication device and / or the second communication device pauses transmission by setting transmission power in a predetermined frequency band to zero.

  Preferably, when data communication is performed between the first communication apparatus and the second communication apparatus using a plurality of subcarriers having different frequencies, the first communication apparatus and / or the second communication apparatus The method further includes a step of suppressing transmission power of one or more subcarriers corresponding to a predetermined frequency band selected from the plurality of subcarriers to a predetermined level.

  Preferably, the first communication device or / and the second communication device further includes a step of suppressing transmission power to a predetermined level for each of a plurality of bands constituting the frequency band.

  Further, according to the present invention, the communication device performs data communication with another communication device via a telephone line, and is selected from the frequency band used for transmission by the communication device in accordance with an external command. A transmission power control unit is provided that suppresses transmission power in a predetermined frequency band that causes interference with an adjacent telephone line to a predetermined level.

  Preferably, the transmission power control means is configured to suppress transmission power of a predetermined frequency band selected from frequency bands used for transmission by other communication devices to a predetermined level in response to a command from the outside. Means for transmitting a transmission power suppression command to the communication device.

  Preferably, the transmission power control means further includes means for receiving a transmission power suppression command from another communication device and suppressing transmission power in a predetermined frequency band to a predetermined level.

  Preferably, the transmission power control means further includes means for stopping transmission by setting transmission power of a predetermined frequency band to zero.

  Preferably, the communication apparatus performs data communication with another communication apparatus using a plurality of subcarriers having different frequencies, and the transmission power control unit is configured to select one or more corresponding to a predetermined frequency band from among the plurality of subcarriers. Means for suppressing transmission power of two or more subcarriers to a predetermined level is further included.

  Preferably, the transmission power control means includes means for suppressing the transmission power to a predetermined level for each of a plurality of bands constituting the frequency band.

  Preferably, the transmission power control means is configured to set the transmission power from 5.2 MHz to 8.5 MHz to zero and the transmission power from 8.5 MHz to 12 MHz to −80 dBm / Hz according to a command from the outside. In addition.

  Preferably, the transmission power control means sets the transmission power from 5.2 MHz to 8.5 MHz to -70 dBm / Hz and the transmission power from 8.5 MHz to 12 MHz to -70 dBm / Hz according to an external command. Means for further comprising:

  Preferably, the transmission power control means sets the transmission power from 138 kHz to 1.1 MHz and the transmission power from 1.3 MHz to 2.0 MHz to zero according to an instruction from the outside, and from 1.1 MHz to 1.3 MHz. It further includes means for setting the transmission power and the transmission power of 2.0 MHz to 3.75 MHz to -70 dBm / Hz.

  Preferably, the transmission power control means further includes means for setting the transmission power from 138 kHz to 640 kHz to zero and setting the transmission power from 640 kHz to 2.0 MHz to −70 dBm / Hz in accordance with an external command.

  According to the present invention, the amount of crosstalk to the adjacent telephone line can be reduced because the transmission power of the frequency band used by another communication method is suppressed to a predetermined level in accordance with an external command. Therefore, it is possible to suppress interference with other communication systems that provide services using adjacent telephone lines.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
In the first embodiment, a DMT (Discrete Multi-Tone) type VDSL will be described.

  In VDSL according to the first embodiment, interference with other communication schemes is suppressed by controlling transmission power of subcarriers arranged at intervals of about 4 kHz.

  FIG. 1 is a schematic configuration diagram of a communication system 100 according to the first embodiment.

  Referring to FIG. 1, a communication system 100 includes a station side device 1 and a terminal side device 2.

  The station side device 1 and the terminal side device 2 are connected via a telephone line.

  The station apparatus 1 includes a storage unit 8, a transmission power control unit 6, an encoder 10, a modulator (IFFT) 12, a parallel / serial (P / S) converter 14, and a digital / analog converter (DAC). ) 16, a driver unit 20, 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. And a decoder 32.

  The storage unit 8 stores a transmission power pattern in which the frequency band and the transmission power of each frequency band are associated with each other. The transmission power pattern is defined in dBm / Hz, which is a unit of transmission power density (PSD) obtained by standardizing transmission power in frequency units. DBm is a logarithm of the power ratio when 1 mW is used as a reference (0 dBm).

  The transmission power control unit 6 receives a setting for suppressing interference with other communication methods, for example, a transmission power pattern number stored in the storage unit 8 from the outside. Then, the transmission power control unit 6 reads the transmission power pattern corresponding to the setting from the storage unit 8 and gives the transmission power pattern to the encoder 10.

  The encoder 10 encodes input data to be transmitted according to the transmission power pattern received from the transmission power control unit 6 and allocates data for each subcarrier. That is, the encoder 10 uses subcarriers included in a predetermined frequency band as predetermined transmission power, and allocates data for each corresponding subcarrier. Then, the encoder 10 outputs the data of each subcarrier to the modulator 12.

  The modulator 12 digitally modulates the data of each subcarrier received from the encoder 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 to the terminal side device 2 via the telephone line. The hybrid circuit 22 outputs an analog signal received from the terminal side device 2 via the telephone line to the low noise amplifier 24. That is, the hybrid circuit 22 isolates the analog signal transmitted to the terminal side device 2 and the analog signal received from the terminal side device 2.

  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). Then, the demodulator 30 outputs the digitally demodulated data for each subcarrier to the decoder 32.

  The decoder 32 restores the original data from the data for each subcarrier received from the demodulator 30 and outputs it to the outside.

  On the other hand, since the terminal side apparatus 2 has the same configuration as the station side apparatus 1, description thereof is omitted.

  FIG. 2 is a flowchart of a transmission power suppression process in the transmission power control unit 6 of the station side device 1 and the terminal side device 2.

  Referring to FIG. 2, transmission power control unit 6 reads a transmission power pattern corresponding to an external setting from storage unit 8 at the start of VDSL connection (step S100).

  The transmission power control unit 6 outputs the read transmission power pattern to the encoder 10 (step S102). Then, the transmission power control unit 6 ends the process.

  As described above, the station-side device 1 and the terminal-side device 2 transmit in a predetermined frequency band that causes interference with an adjacent telephone line selected from the frequency bands used for transmission according to the setting from the outside. Data communication is performed while suppressing power to a predetermined level.

  In addition, as a method of giving the setting to the transmission power control unit 6, for example, a method using a setting personal computer or the like via an interface such as Ethernet (registered trademark), USB (Universal Serial Bus) and RS-232C, or a dip switch There is a way to do it.

  Further, instead of storing the transmission power pattern in the storage unit 8, a transmission power pattern may be given to the transmission power control unit 6 from a setting personal computer or the like.

(Interference suppression from VDSL to HomePNA)
FIG. 3 is a diagram showing the frequency bands used for VDSL and HomePNA.

  Referring to FIG. 3, VDSL performs data communication by dividing a frequency band of 12 MHz or less into four bands. Corresponding to upstream and downstream data communications, downstream band 1 (138 kHz to 3.75 MHz), upstream band 1 (3.75 MHz to 5.2 MHz), downstream band 2 (5.2 MHz to 8.5 MHz) and Uplink band 2 (8.5 MHz to 12 MHz) is allocated.

  In “G.993.1”, two options are defined for the downstream band 1, that is, a case where a frequency band of 640 kHz or less is not used and a case where a frequency band of 1.1 MHz or less is not used. Selected by.

  On the other hand, HomePNA performs data communication by temporally switching between uplink and downlink using a frequency band of 4.0 MHz or higher.

  In HomePNA 1.0, a frequency band from 4.0 MHz to 11.5 MHz is used. In HomePNA 2.0, a frequency band from 4.0 MHz to 11.0 MHz is used.

  As described above, in both HomePNA 1.0 and 2.0, there is a frequency band that overlaps the VDSL use frequency band. Therefore, in order to suppress interference from VDSL to HomePNA, it is necessary to suppress transmission power in a frequency band where VDSL and HomePNA overlap.

  Note that the standard transmission power of VDSL is −60 dBm / Hz as recommended in “G.993.1”.

  FIG. 4 is a diagram illustrating a case where transmission is paused in band units in a frequency band that overlaps the frequency band used for HomePNA.

  Referring to FIG. 1 and FIG. 4, the transmission power control unit 6 of the station side device 1 receives a setting from the outside, and sets a transmission power pattern in which the transmission power of the downlink band 2 that is its own transmission band is zero. This is given to the encoder 10 of the station side device 1. When the transmission power becomes zero, the encoder 10 cannot allocate data, so transmission in the downstream band 2 is suspended.

  Similarly, the transmission power control unit 6 of the terminal side device 2 receives the setting from the outside, and sets the transmission power pattern in which the transmission power of the uplink band 2 that is its own transmission band is zero to the encoder of the terminal side device 2. 10 and transmission of the upstream band 2 is suspended.

  In this way, by setting the transmission power to zero for each band, it is possible to suppress interference from VDSL to HomePNA.

  FIG. 5 is a diagram illustrating a case where transmission power is suppressed in band units in a frequency band that overlaps with the frequency band used for HomePNA.

  Referring to FIG. 1 and FIG. 5, the transmission power control unit 6 of the station side device 1 receives a setting from the outside, and sets a transmission power pattern for suppressing the transmission power of the downlink band 2 that is its own transmission band. To the encoder 10 of the side device 1. In addition, the transmission power control unit 6 of the terminal-side device 2 receives a setting from the outside and gives a transmission power pattern for suppressing the transmission power of the uplink band 2 that is its own transmission band to the encoder 10 of the terminal-side device 2. .

  Thus, when the transmission power is suppressed to a predetermined level in band units, the encoder 10 does not need to suppress the transmission power for each of the subcarriers, and thus is inexpensive. Further, since the transmission power pattern stored in the storage unit 8 is simplified, the storage capacity of the storage unit 8 can be reduced.

  By the way, since the amount of crosstalk changes greatly depending on the adjacent distance between telephone lines, etc., in order to maintain the communication speed by effectively using the allocated frequency band while suppressing interference with other communication methods, It is desirable to suppress transmission power for each necessary frequency band in each band.

  FIG. 6 is a diagram illustrating a case where transmission power is suppressed for each frequency band in the band in a frequency band that overlaps the frequency band used for HomePNA.

  Referring to FIG. 1 and FIG. 6, the transmission power control unit 6 of the station side device 1 receives the setting from the outside, and sets the transmission power of the first half (low frequency side) of the downlink band 2 that is its own transmission band. A transmission power pattern in which the transmission power of the second half of the downstream band 2 (high frequency side) is BdBm / Hz is given to the encoder 10 of the station side apparatus 1 as AdBm / Hz.

  Similarly, the transmission power control unit 6 of the terminal-side device 2 receives the setting from the outside, sets the transmission power of the second half (high frequency side) of the uplink band 1, which is its own transmission band, to CdBm / Hz. A transmission power pattern in which the transmission power of the first half of band 2 (low frequency side) is set to DdBm / Hz and the transmission power of the second half of uplink band 2 (high frequency side) is set to EdBm / Hz is given to the encoder 10 of the terminal device 2 .

  In this way, by suppressing each frequency band to a predetermined transmission power, it is possible to maintain the communication speed by effectively using the allocated frequency band while suppressing interference with other communication methods.

  Further, since transmission power for each subcarrier can be set in the DMT-type VDSL, the transmission power control unit 6 gives a transmission power pattern in which transmission power is set for each subcarrier included in the overlapping frequency band to the encoder 10. be able to.

  Table 1 is an example of a transmission power pattern that can suppress interference from VDSL to HomePNA when services of VDSL and HomePNA are provided via adjacent telephone lines. Note that the transmission power in a frequency band not shown in Table 1 is −60 dBm / Hz.

  Referring to Table 1, transmission power pattern 1 is a transmission power pattern when no interference from VDSL to HomePNA is given. The transmission power pattern 2 is a transmission power pattern when the interference from the VDSL to the HomePNA is the same level as the mutual interference between the HomePNAs.

  The transmission power control unit 6 of the station side device 1 receives the setting of the transmission power pattern 1 and sends a transmission power pattern in which the transmission power of the downlink band 2 that is its own transmission band is zero to the encoder 10 of the station side device 1. And the transmission of the downstream band 2 is paused.

  On the other hand, the transmission power control unit 6 of the terminal side device 2 receives the setting of the transmission power pattern 1, and sets the transmission power pattern in which the transmission power of the uplink band 2 that is its own transmission band is −80 dBm / Hz. 2 to the encoder 10.

  Similarly, the transmission power control unit 6 of the station side apparatus 1 receives the setting of the transmission power pattern 2 from the outside, and sets the transmission power of the downlink band 2 that is its own transmission band to −70 dBm / Hz. The pattern is given to the encoder 10 of the station side device 1, and the transmission power control unit 6 of the terminal side device 2 receives the setting of the transmission power pattern 2 from the outside, and transmits the transmission power of the upstream band 2 which is its own transmission band. A transmission power pattern of −70 dBm / Hz is given to the encoder 10 of the terminal-side device 2.

(Interference suppression from VDSL to ADSL)
FIG. 7 is a diagram showing frequency bands used for VDSL and ADSL.

  Referring to FIG. 7, ADSL includes ADSL (G.lite) recommended in “G.992.2”, ADSL (G.dmt) recommended in “G.992.1”, “ There are four types of ADSL2 recommended in “G.992.3” and ADSL2plus recommended in “G.992.5”.

  Each ADSL performs data communication by dividing the allocated frequency band into two bands.

  Downstream data communication is assigned downstream bands of 138 kHz to 552 kHz, 138 kHz to 1.1 MHz, 138 kHz to 2.2 MHz, and 138 kHz to 3.75 MHz, respectively.

  As described above, in any ADSL, the downstream band overlaps with the frequency band of downstream band 1 of VDSL. Therefore, in order to suppress the interference from VDSL to ADSL, it is necessary to suppress the transmission power of VDSL downstream band 1.

  FIG. 8 is a diagram illustrating a case where transmission of the VDSL downlink band 1 overlapping with the ADSL downlink band is suspended.

  Referring to FIG. 8, the transmission power control unit 6 of the station side device 1 receives the setting from the outside, sets the transmission power of the downlink band 1 that is its own transmission band to zero, and pauses transmission.

  Note that the upstream bands 1 and 2 of VDSL do not overlap with the frequency bands of ADSL, so it is not necessary to give any setting to the terminal side device 2.

  In this way, by setting the transmission power in the frequency band overlapping with the frequency band used for ADSL to zero, it is possible to prevent any ADSL from causing any interference.

  Table 2 shows an example of transmission power for each frequency band that can suppress interference from VDSL to ADSL2 or ADSL2plus when a service between VDSL and ADSL2 or ADSL2plus is provided via an adjacent telephone line. Note that the transmission power in the frequency band not shown in Table 2 is −60 dBm / Hz.

  Referring to Table 2, transmission power pattern 3 is a transmission power pattern in the case where no interference from VDSL to ADSL2 or ADSL2plus is given. The transmission power pattern 4 is a transmission power pattern when the interference from VDSL to ADSL2 or ADSL2plus becomes the same level as the mutual interference between ADSL2 or ADSL2plus.

  The transmission power control unit 6 of the station side device 1 receives the setting of the transmission power pattern 3 and transmits the transmission power of 138 kHz to 1.1 MHz and 1.3 MHz to 2.0 MHz in the downlink band 1 that is its own transmission band. Is applied to the encoder 10 of the station apparatus 1 to stop transmission, and the transmission power of 1.1 MHz to 1.3 MHz and 2.0 MHz to 3.75 MHz is set to -70 dBm / Hz. The transmission power pattern is given to the encoder 10 of the station side device 1.

  Similarly, the transmission power control unit 6 of the station side device 1 receives the setting of the transmission power pattern 4 and sets the transmission power of 138 kHz to 640 kHz to zero in the downlink band 1 that is its own transmission band. A pattern is given to the encoder 10 of the station side apparatus 1 to stop transmission, and a transmission power pattern with a transmission power of 640 kHz to 2.0 MHz of −70 dBm / Hz is given to the encoder 10 of the station side apparatus 1.

  By the way, in ADSL, training is performed before starting data communication, and a frequency band that can be used is determined according to the state of the telephone line, for example, the distance of the telephone line and the noise level from the surroundings. In particular, the longer the telephone line between the telephone base station and the terminal-side device, the higher the attenuation of the high frequency signal, so that the upper limit of the usable frequency is limited and the usable frequency band is narrowed.

  That is, when the ADSL service is provided on the telephone line adjacent to the VDSL, the VDSL to the ADSL is dependent on the distance of the telephone line between the telephone base station that provides the ADSL service and the terminal side device. The frequency band that causes interference changes.

  Therefore, the distance from the telephone base station that provides the ADSL service is investigated in advance, and the upper limit of the frequency that can be used for ADSL is estimated, so that the ADSL is allocated while suppressing interference. The communication speed can be maintained by effectively using the frequency band.

(Interference suppression from VDSL to non-standard VDSL)
FIG. 9 is a diagram illustrating frequency bands used as an example of VDSL and non-standard VDSL.

  Referring to FIG. 9, non-standard VDSL performs data communication by dividing a predetermined frequency band into two bands. Corresponding to downlink and uplink data communication, a downlink band (138 kHz to 3.75 MHz) and an uplink band (5.2 MHz to 8.5 MHz) are allocated.

  As described above, in the non-standard VDSL, the downstream band overlaps the frequency band of the downstream band 1 with VDSL and the upstream band overlaps with the frequency band of the downstream band 2 with VDSL. Therefore, in order to suppress interference from VDSL to non-standard VDSL, it is necessary to suppress the transmission power of VDSL downlink band 1 and downlink hand 2.

  In the same manner as described above, the transmission power control unit 6 of the station side device 1 receives the setting from the outside and suppresses the transmission power of the downlink bands 1 and 2 that are its own transmission bands.

  Note that the transmission power control unit 6 cannot suspend transmissions in the downstream bands 1 and 2 at the same time. This is because data communication cannot be performed between the station-side device 1 and the terminal-side device 2 when all downlink transmissions are suspended.

  As described above, the transmission power control unit 6 can perform transmission suspension or transmission power suppression for each band or for each frequency band within the band, and therefore provides services using adjacent telephone lines. Interference with other communication systems can be suppressed.

  In addition, since the transmission power can be controlled for each subcarrier in the VDSL of the DMT method, in addition to the above, other communication methods can be used by using a transmission power pattern composed of an optimal combination of a target frequency band and transmission power. Needless to say, the interference with can be suppressed.

  According to the first embodiment, the station-side device and the terminal-side device suppress the transmission power of the frequency band used by another communication method to a predetermined level according to the setting from the outside. The amount of crosstalk to the line can be reduced. Therefore, it is possible to suppress interference with other communication systems that provide services using adjacent telephone lines, in particular, the HomePNA system, all ADSL systems, and non-standard VDSL systems.

[Embodiment 2]
In the first embodiment described above, a case has been described in which settings are given to the station side device and the terminal side device to suppress transmission power.

  On the other hand, in the second embodiment, a case will be described in which transmission power is suppressed by giving a setting only to the station side device.

  FIG. 10 is a schematic configuration diagram of a communication system 200 according to the second embodiment.

  Referring to FIG. 10, the communication system 200 includes a station side device 3 and a terminal side device 4.

  The station side device 3 is obtained by replacing the transmission power control unit 6 of the station side device 1 in the communication system 100 shown in FIG.

  In addition, the storage unit 8 of the station side device 3 stores a transmission power pattern in which uplink and downlink frequency bands and transmission power are associated with each other.

  The transmission power control unit 40 receives a setting for suppressing interference with other communication methods, for example, a transmission power pattern number stored in the storage unit 8 from the outside. Then, the transmission power control unit 6 reads the transmission power pattern from the storage unit 8 and separates the transmission power pattern in the upstream frequency band from the transmission power pattern in the downstream frequency band. Furthermore, the transmission power control unit 6 gives the transmission power pattern of the downlink frequency band to the encoder 10 of the station side device 3, and uses the transmission power pattern of the uplink frequency band as a transmission power suppression command to the terminal side device 4 via the encoder 10. Send.

  In this way, the transmission power control unit 40 suppresses transmission power in a predetermined frequency band selected from the frequency bands used for transmission.

  The terminal side device 4 is obtained by replacing the transmission power control unit 6 of the terminal side device 2 in the communication system 100 shown in FIG.

  The transmission power control unit 42 receives the transmission power pattern of the uplink frequency band transmitted from the transmission power control unit 40 of the station side device 3 via the decoder 32 of the terminal side device 4. Then, the transmission power control unit 42 gives the received transmission power pattern of the uplink frequency band to the encoder 10 of the terminal device 4.

  In this way, the transmission power control unit 42 suppresses transmission power in a predetermined frequency band selected from the frequency bands used for transmission.

  FIG. 11 is a flowchart of transmission power suppression processing in the transmission power control unit 40 of the station side device 3.

  Referring to FIG. 11, transmission power control unit 40 reads a transmission power pattern corresponding to an external setting from storage unit 8 at the start of VDSL connection (step S200).

  The transmission power control unit 40 transmits the transmission power pattern of the uplink frequency band to the terminal side device 4 (step S202). That is, the transmission power control unit 40 transmits a transmission power suppression command to the terminal side device 4.

  The transmission power control unit 40 outputs the transmission power pattern of the downlink frequency band to the encoder 10 (step S204). Then, the transmission power control unit 40 ends the process.

  FIG. 12 is a flowchart of the transmission power suppression process in the transmission power control unit 42 of the terminal-side device 4.

  Referring to FIG. 12, the transmission power control unit 42 outputs the transmission power pattern received from the station side device 3 to the encoder 10 at the start of VDSL connection (step S300). Then, the transmission power control unit 42 ends the process.

  Thereafter, similarly to the above-described first embodiment, a transmission power pattern for suppressing interference with other communication schemes that provide services using adjacent telephone lines is set.

  In addition, although the case where setting was given with respect to the station side apparatus 3 was demonstrated, setting was performed with respect to the terminal side apparatus by using the station side apparatus 3 as a terminal side apparatus and using the terminal side apparatus 4 as a station side apparatus. It goes without saying that the configuration given can be realized.

  According to the second embodiment, in addition to the effect of the first embodiment, when the station side device receives the setting of the transmission power pattern, it suppresses its own transmission power according to the transmission power pattern, and further to the terminal side device. A transmission power pattern that is a transmission power suppression command is transmitted. Therefore, since the user only needs to give settings to the station-side apparatus, work efficiency and management can be facilitated in a large-scale communication system in which many terminal-side apparatuses exist.

  In the first and second embodiments described above, the VMT of the DMT method has been described. However, the VDSL also has a QAM (Quadratic Amplitude Modulation) method.

  The QAM method is a method of assigning frequency bands to upstream and downstream bands and performing data communication using a single carrier for each assigned band.

  Therefore, by controlling the transmission power of each carrier wave, that is, the transmission power in band units, as in the first and second embodiments, interference with other communication systems that provide services using adjacent telephone lines. Can be suppressed.

  In addition, when only one uplink band and one downlink band are allocated, if the transmission power is suppressed in band units, the communication speed is significantly reduced. Therefore, transmission power can be suppressed for each frequency band in the band by transmitting through a band-pass filter whose attenuation characteristics change according to the setting from the outside. Therefore, similarly to the DMT system, the communication speed can be maintained while suppressing interference with other communication systems that provide services using adjacent telephone lines.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of a communication system according to a first embodiment. It is a flowchart of the transmission power suppression process in the transmission power control part of a station side apparatus and a terminal side apparatus. It is a figure which shows the use frequency band of VDSL and HomePNA. It is a figure which shows the case where transmission is suspended per band in the frequency band which overlaps with the use frequency band of HomePNA. It is a figure which shows the case where transmission power is suppressed per band in the frequency band which overlaps with the use frequency band of HomePNA. It is a figure which shows the case where transmission power is suppressed for every frequency band in a band in the frequency band which overlaps the use frequency band of HomePNA. It is a figure which shows the use frequency band of VDSL and ADSL. It is a figure which shows the case where transmission of the downstream band of VDSL which overlaps with the downstream band of ADSL is suspended. It is a figure which shows the use frequency band of VDSL and nonstandard VDSL. FIG. 5 is a schematic configuration diagram of a communication system according to a second embodiment. It is a flowchart of the transmission power suppression process in the transmission power control part of a station side apparatus. It is a flowchart of the transmission power suppression process in the transmission power control part of a terminal side apparatus. It is a conceptual diagram in case the service of VDSL and HomePNA is provided via the adjacent telephone line. It is a conceptual diagram in case the service of VDSL and ADSL is provided through the adjacent telephone line in a building.

Explanation of symbols

  1, 3 station side device, 2, 4 terminal side device, 6, 40, 42 transmission power control unit, 8 storage unit, 10 encoder, 12 modulator (IFFT), 14 parallel-serial (P / S) converter, 16 digital-analog converter (DAC), 20 driver section, 22 hybrid circuit, 24 low noise amplifier, 26 analog-digital converter (ADC), 28 serial parallel (S / P) converter, 30 demodulator (FFT) ), 32 decoder, 100, 200 communication system.

Claims (20)

A communication system comprising a first communication device and a second communication device that performs data communication with the first communication device via a telephone line,
The first communication device transmits power in a predetermined frequency band that causes interference with an adjacent telephone line selected from among the frequency bands used for transmission by the first communication device in response to a command from the outside. To a predetermined level,
The second communication device transmits power in a predetermined frequency band that causes interference with an adjacent telephone line selected from among the frequency bands used for transmission by the second communication device in response to a command from the outside. A communication system that suppresses the signal to a predetermined level. The first communication device suppresses the transmission power of the predetermined frequency band selected from the frequency bands used for transmission by the second communication device to a predetermined level in response to a command from the outside. Is transmitted to the second communication device,
The communication system according to claim 1, wherein the second communication device receives the transmission power suppression command from the first communication device and suppresses the transmission power of the predetermined frequency band to a predetermined level.   The communication system according to claim 1 or 2, wherein the first communication device and / or the second communication device pauses transmission with zero transmission power in the predetermined frequency band. The first communication device and the second communication device perform data communication using a plurality of subcarriers having different frequencies,
The first communication device or / and the second communication device may transmit transmission power of one or more subcarriers corresponding to the predetermined frequency band selected from the plurality of subcarriers to the predetermined The communication system according to claim 1, wherein the communication system is suppressed to a level.   5. The device according to claim 1, wherein the first communication device and / or the second communication device suppresses transmission power to the predetermined level for each of a plurality of bands constituting a frequency band. The communication system described. A communication method for performing data communication between a first communication device and a second communication device via a telephone line,
The step of suppressing the transmission power in a predetermined frequency band that causes interference with an adjacent telephone line selected from the frequency band used for transmission by the first communication device to a predetermined level in response to a command from the outside When,
The step of suppressing the transmission power in a predetermined frequency band that causes interference with an adjacent telephone line selected from among the frequency bands used for transmission by the second communication device to a predetermined level in response to a command from the outside And a communication method. In response to a command from the outside, a transmission power suppression command for suppressing the transmission power of the predetermined frequency band selected from the frequency bands used for transmission by the second communication device to a predetermined level Transmitting from one communication device to the second communication device;
The method further comprises a step of receiving the transmission power suppression command transmitted from the first communication device, and the second communication device suppressing transmission power of the predetermined frequency band to a predetermined level. The communication method described in 1.   The communication method according to claim 6 or 7, further comprising a step in which the first communication device and / or the second communication device pauses transmission by setting transmission power of the predetermined frequency band to zero.   When data communication is performed between the first communication device and the second communication device using a plurality of subcarriers having different frequencies, the first communication device and / or the second communication device The method further includes a step of suppressing transmission power of one or more subcarriers corresponding to the predetermined frequency band selected from the plurality of subcarriers to the predetermined level. The communication method according to claim 1.   10. The method according to claim 6, further comprising a step of suppressing transmission power to the predetermined level for each of a plurality of bands in which the first communication device and / or the second communication device constitutes a frequency band. The communication method according to Item 1. A communication device that performs data communication with another communication device via a telephone line,
Transmission power control means for suppressing transmission power in a predetermined frequency band that causes interference to an adjacent telephone line selected from among frequency bands used for transmission by the communication device to a predetermined level in response to a command from the outside A communication device comprising:   The transmission power control means is configured to suppress the transmission power of the predetermined frequency band selected from frequency bands used by other communication devices for transmission to a predetermined level according to a command from the outside. The communication device according to claim 11, further comprising means for transmitting a transmission power suppression command to the communication device.   The communication apparatus according to claim 11 or 12, wherein the transmission power control means further includes means for receiving a transmission power suppression command from another communication apparatus and suppressing the transmission power of the predetermined frequency band to a predetermined level. .   The communication apparatus according to any one of claims 11 to 13, wherein the transmission power control means further includes means for stopping transmission by setting transmission power of the predetermined frequency band to zero. The communication device performs data communication with other communication devices using a plurality of subcarriers having different frequencies.
The transmission power control means further includes means for suppressing transmission power of one or more subcarriers corresponding to the predetermined frequency band from the plurality of subcarriers to the predetermined level. The communication apparatus of any one of -14.   The communication device according to any one of claims 11 to 15, wherein the transmission power control means includes means for suppressing transmission power to the predetermined level for each of a plurality of bands constituting a frequency band.   The transmission power control means further includes means for setting the transmission power from 5.2 MHz to 8.5 MHz to zero and the transmission power from 8.5 MHz to 12 MHz to −80 dBm / Hz in accordance with an external command. The communication device according to any one of claims 11 to 16.   The transmission power control means is means for setting the transmission power from 5.2 MHz to 8.5 MHz to -70 dBm / Hz and the transmission power from 8.5 MHz to 12 MHz to -70 dBm / Hz in accordance with an external command. The communication device according to claim 11, further comprising:   The transmission power control means sets transmission power from 138 kHz to 1.1 MHz and transmission power from 1.3 MHz to 2.0 MHz to zero in accordance with an external command, and transmission power from 1.1 MHz to 1.3 MHz. The communication device according to any one of claims 11 to 18, further comprising means for setting a transmission power of 2.0 MHz to 3.75 MHz to -70 dBm / Hz.   The transmission power control means further includes means for setting a transmission power from 138 kHz to 640 kHz to zero and a transmission power from 640 kHz to 2.0 MHz to -70 dBm / Hz according to a command from the outside. The communication apparatus of any one of -18.

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