JP2018074464A - Communication system, communication device, transmission method, reception method, and, communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reduction of communication quality by preventing interference of communication between mutually proximate metal lines of multiple communication systems of which the available frequency bands are partially overlapped, in accordance with a simple method.SOLUTION: The present invention relates to a communication system to be used for a time division duplexing communication system that may coexist with a frequency division duplexing communication system. The communication system comprises: a basic communication part which uses a second frequency band partially overlapped with a first frequency band to be used for frequency division duplexing and wider than the first frequency band and communicates in accordance with a signal to which multicarrier modulation is applied; and a band limit part which allocates dummy data to a subcarrier within a range of the first frequency band in the case of transmission when interference of communication in the first frequency band is estimated with the frequency division duplexing communication system, allocates data that should be originally communicated to the other subcarriers, and prevents a signal of a subcarrier on which the dummy data are allocated from going out on a metal line by a filter.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a communication system, a communication apparatus, a transmission method, a reception method, and a communication method.

  For example, in an apartment house, after drawing optical fiber to the central office (CO) in the building, it is connected to the customer premises equipment (CPE: Customer Premises Equipment) using existing metal lines for fixed telephones. VDSL (Very High Speed Digital Subscriber Line) technology is used. In recent years, as a DSL technology capable of transmission at higher speed than VDSL, G.P. Fast (ITU-T G.9701) has attracted attention (see, for example, Non-Patent Document 1).

  On the other hand, generally in a housing complex, the user of each house can freely select a communication service provider. As a result, for example, a VDSL communication system and G. The fast communication system coexists. In addition, in an apartment house, there are places where metal lines are wired in bundles due to the structure, and a plurality of sets of metal lines are close to each other. Further, regarding the frequency band to be used, V.I. Fast includes the frequency band of VDSL and is wider than that. Therefore, communication interference due to leakage of communication signals may occur in the overlapping frequency bands. When communication interference occurs, the received signal is suppressed, resulting in a decrease in communication quality such as a decrease in communication speed.

  Therefore, a technique for performing vectoring processing has already been proposed in order to reduce such communication interference (see, for example, Patent Document 1). Interference mitigation by vectoring involves processing the frequency spectrum corresponding to the leaked signal in advance in order to cancel the leaked signal that becomes the interference source. For this purpose, for example, it is necessary to constantly monitor signals leaking from communication systems of other companies.

Japanese Patent Laid-Open No. 2006-86419

"G.fast standardization trend" NTT Technology Journal May 2016

However, vectoring requires constant monitoring of signals leaking from other companies' communication systems, which places a heavy processing burden on communication devices.
In view of such problems, the present invention prevents communication interference between adjacent metal lines in a plurality of communication systems in which usable frequency bands are partially overlapped with each other by a simple method, and reduces communication quality. The purpose is to prevent.

[Communications system]
The communication system according to one expression of the present invention includes a plurality of communication systems that communicate via a metal line between a master unit and a slave unit, and a communication system in which the metal lines of each communication system are close to each other Used in a time division duplex communication system that can coexist with a frequency division duplex communication system, and the time division duplex communication system is the frequency division duplex communication system. A basic communication unit that partially communicates with a first frequency band to be used, uses a second frequency band wider than the first frequency band, and performs communication using a signal subjected to multicarrier modulation; and the frequency division duplexer. And assigning dummy data to subcarriers within the range of the first frequency band at the time of transmission when communication interference in the first frequency band is expected with the other communication carrier, and other subcarriers. In Allocates the data to be communicated originally has, and suppresses bandwidth limiter by a filter that the signal of the subcarrier in which the dummy data is superimposed exits on the metal line.

[Communication device]
A communication device according to an expression of the present invention is a communication device as the parent device or a child device constituting a communication system that communicates between a parent device and a child device via a metal line, and is used in another communication system A basic communication unit that communicates with a signal that is time-division duplexed and subjected to multicarrier modulation using a second frequency band that partially overlaps the first frequency band that can be performed and is wider than the first frequency band And dummy data is allocated to subcarriers within the range of the first frequency band at the time of transmission when communication interference in the first frequency band is expected with the other communication system. The subcarrier is provided with a band limiting unit that allocates data to be originally communicated and suppresses the subcarrier signal carrying the dummy data from going out on the metal line by a filter. .

[Sending method]
A transmission method according to an expression of the present invention is a transmission method in the case where communication is performed between a parent device and a child device via a metal line, and communication is performed from another communication system performing communication using frequency division duplex. Whether or not it is necessary to limit at least a part of the first frequency band when a signal leaking to the system is received and the frequency band used in the frequency division duplex is the first frequency band If a band limitation is not required, the second frequency band that partially overlaps the first frequency band and that is wider than the first frequency band is used for time-division duplex and multi-carrier. When transmission is performed using a modulated signal and band limitation is required, dummy data is allocated to necessary subcarriers within the first frequency band, and data to be originally communicated is transmitted to other subcarriers. Assign and send Rutotomoni, suppresses by a filter that the signal of the sub-carriers that the dummy data was riding went out on the metal line.

[Reception method]
A reception method according to an expression of the present invention is a reception method when communication is performed between a parent device and a child device via a metal line, and is a subcarrier in a frequency band used for frequency division duplex communication. When a signal to which data to be originally communicated is assigned is received for the other subcarriers, the dummy data is excluded after demodulation.

[Communication method]
Further, a communication method according to an expression of the present invention is a communication method for communicating between a master unit and a slave unit via a metal line, and is communicated from another communication system that is communicating by frequency division duplex. Whether or not it is necessary to limit at least a part of the first frequency band when a signal leaking to the system is received and the frequency band used in the frequency division duplex is the first frequency band If a band limitation is not required, the second frequency band that partially overlaps the first frequency band and that is wider than the first frequency band is used for time-division duplex and multi-carrier. When transmission is performed using a modulated signal and band limitation is required, dummy data is allocated to necessary subcarriers within the first frequency band, and data to be originally communicated is transmitted to other subcarriers. Assign and send In addition, when a signal on which the dummy data is allocated is received from a communication partner, the subcarrier signal carrying the dummy data is suppressed from going out on the metal line by a filter. A communication method for excluding the dummy data after demodulation.

  According to the present invention, it is possible to prevent communication interference between adjacent metal lines in a plurality of communication systems in which usable frequency bands are partially overlapped with each other by a simple method, and to prevent deterioration in communication quality. Can do.

VDSL2 (ITU-T G.993.2) and G. It is a figure which shows contrast of the frequency band to be used with fast. G. Communicates with time division duplex. It is a figure which shows the reference example of the communication system in which the communication system of fast and the communication system of VDSL2 which communicates by frequency division duplex are mixed. It is a figure showing signal leakage along with uplink / downlink signal transmission / reception on a transmission / reception time chart. G. Communicates with time division duplex. It is a figure which shows an example of the communication system with which the communication system of fast (band limitation is possible) and the communication system of VDSL2 which communicates by frequency division duplex are mixed. VDSL2 and band-limited G.264. It is a figure which shows contrast of the frequency band to be used with fast. It is a circuit block diagram which shows the outline | summary of transmission / reception of an aggregation apparatus or a household device. It is a block diagram which shows the process by the side of transmission, such as a basic communication part in a communication apparatus. It is a block diagram which shows the process by the side of reception, such as a basic communication part. It is a block diagram which shows the process of the transmission side containing a band limiting part in a communication apparatus. It is a block diagram which shows the process of the receiving side in a communication apparatus. It is a figure which shows the subcarrier of an OFDM signal.

[Summary of Embodiment]
The gist of the embodiment of the present invention includes at least the following.

[Communications system]
(1) This is a communication system used for a communication system in which there are a plurality of communication systems communicating via a metal line between a master unit and a slave unit, and the metal lines of each communication system are close to each other. The time division duplex communication system can coexist with the frequency division duplex communication system, and the time division duplex communication system is a first one used in the frequency division duplex. A basic communication section that partially communicates with a frequency band, uses a second frequency band wider than the first frequency band, and performs communication using a signal subjected to multicarrier modulation; and a communication system of the frequency division duplex; During transmission when communication interference in the first frequency band is expected, dummy data is allocated to subcarriers within the range of the first frequency band, and communication is originally performed on other subcarriers. Data to be Allocates a communication system having a suppressing band-limiting unit by a filter that the signal of the subcarrier in which the dummy data is superimposed exits on the metal line.

In such a communication system, it is possible to perform modulation in which dummy data is allocated to subcarriers as much as necessary within a first frequency band range in which communication interference is expected, and the subcarriers on which the dummy data are placed Since the transmission is suppressed by the filter and the transmission to the metal line is suppressed, it is possible to prevent communication interference between adjacent metal lines. In addition, since data to be originally communicated in the communication system is assigned to other subcarriers, communication contents are not lost.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.
Note that such a communication system is applicable not only when there is communication interference, but also when there is no communication interference, or when communication interference is initially present but then disappears.

(2) Also, in the communication system of (1), for example, when a signal is received from a communication partner, a band information acquisition unit that acquires band information related to frequency band assignment after demodulation, and a dummy based on the band information When there is a subcarrier to which data is assigned, a dummy data exclusion unit that excludes dummy data from the demodulated signal may be provided.
In this case, it is possible to completely exclude dummy data or some unnecessary mixed data that is attenuated by passing through the filter on the transmission side, but remains on the reception side.

(3) Moreover, in the communication system of (1) or (2), the filter is provided on at least the parent device side among the parent device and the child device when the interference of the communication is expected. It may be configured as follows.
In this case, since it is “at least”, it is possible to omit the filter on the handset side. For example, when a plurality of communication systems “live together” in an apartment house, the child devices are distributed to each house, but the parent devices are concentrated in one place. Therefore, the base unit side is in a situation where a plurality of metal lines are close to each other and can be transmitted / received more easily than the base unit side. Therefore, even if “interference of communication is expected” as the communication system, it may be only on the parent device side. In such a case, the filter can be omitted on the handset side.

[Communication device]
(4) On the other hand, this is a communication device as the master unit or slave unit that constitutes a communication system that communicates between the master unit and the slave unit via a metal line, and can be used in other communication systems. A basic communication unit that partially communicates with a signal that has been subjected to time division duplex and multi-carrier modulation using a second frequency band that partially overlaps one frequency band and is wider than the first frequency band; Dummy data is allocated to subcarriers within the first frequency band at the time of transmission when communication interference in the first frequency band is expected with other communication systems, and other subcarriers A bandwidth limiting unit that allocates data to be originally communicated and suppresses a subcarrier signal carrying the dummy data from going out on the metal line by a filter. is there.

In such a communication apparatus, it is possible to perform modulation in which dummy data is allocated to subcarriers as much as necessary within the range of the first frequency band in which communication interference is expected, and the subcarriers on which the dummy data are placed Since the transmission is suppressed by the filter and the transmission to the metal line is suppressed, it is possible to prevent communication interference between adjacent metal lines. In addition, since the data to be originally communicated in the communication apparatus is assigned to other subcarriers, the communication content is not lost.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.
Note that such a communication apparatus is applicable not only when there is communication interference, but also when there is no communication interference, or when there is communication interference at first, but then disappears.

(5) In the communication device of (4), at the time of reception, a leakage determination unit that detects a signal leakage from another communication system based on the demodulated signal, and at the time of transmission based on the signal leakage The information processing apparatus may further include a band information determining unit that determines a subcarrier to which the dummy data is allocated and a subcarrier to which data to be originally communicated is allocated.
In this case, in the demodulated signal, for example, the S / N ratio is good, but if an error is detected, it is expected that communication interference occurs. In such a case, dummy data can be allocated to a necessary and sufficient number of subcarriers by appropriately selecting subcarriers to which dummy data is allocated.

[Sending method]
(6) From the viewpoint of the transmission method, it is a transmission method in the case where communication is performed between a parent device and a child device via a metal line, and from the other communication systems communicating by frequency division duplex, the own communication system If the frequency band used in the frequency division duplex is the first frequency band, whether or not it is necessary to limit the band of at least a part of the first frequency band. If it is determined and no band limitation is required, time division duplex and multicarrier modulation are performed using a second frequency band that partially overlaps the first frequency band and is wider than the first frequency band. When a band limit is required, dummy data is assigned to necessary subcarriers within the first frequency band, and data to be originally communicated is transmitted to other subcarriers. Assign and send Together, it prevents the signal of the sub-carriers that the dummy data was riding went out on the metal line by the filter, which is a transmission method.

In such a transmission method, it is possible to perform modulation in which dummy data is allocated to subcarriers as much as necessary within the range of the first frequency band in which communication interference is expected, and the subcarriers on which the dummy data are placed Since the transmission is suppressed by the filter and the transmission to the metal line is suppressed, it is possible to prevent communication interference between adjacent metal lines. In addition, since data to be originally communicated in the communication system is assigned to other subcarriers, communication contents are not lost.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.

[Reception method]
(7) From the viewpoint of the reception method, this is a reception method when communication is performed between the master unit and the slave unit via a metal line, and dummy data is transmitted to subcarriers in a frequency band used by frequency division duplex communication. Is received, and when the signal to which data to be originally communicated is assigned is received, the dummy data is excluded after demodulation.
In such a reception method, dummy data assigned to subcarriers in a frequency band in which communication interference occurs can be excluded after reception, and data to be originally communicated can be received.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.

[Communication method]
(8) From the viewpoint of the communication method (transmission / reception method), it is a communication method for communicating via a metal line between the master unit and the slave unit, and from other communication systems communicating by frequency division duplex When a signal leaking to its own communication system is received and the frequency band used in the frequency division duplex is the first frequency band, it is necessary to limit the band of at least a part of the first frequency band. And if no band limitation is required, a second frequency band that partially overlaps the first frequency band and is wider than the first frequency band, is time-division duplex, and When transmission is performed using a signal subjected to multicarrier modulation and band limitation is required, dummy data is allocated to necessary subcarriers within the first frequency band range, and other subcarriers are originally communicated. Allocate the data to be And transmits to Te, the signal of a subcarrier which the dummy data is superimposed are suppressed by a filter that exits on the metal lines, whereas,
In the communication method, the dummy data is excluded after demodulation when a signal to which the dummy data is assigned is received from a communication partner.

In such a communication method, it is possible to perform modulation in which dummy data is allocated to subcarriers as much as necessary within the range of the first frequency band in which communication interference is expected, and the subcarriers on which the dummy data are placed Since the transmission is suppressed by the filter and the transmission to the metal line is suppressed, it is possible to prevent communication interference between adjacent metal lines. In addition, data to be originally communicated in the communication device is assigned to other subcarriers, so communication contents are not lost.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.

[Details of the embodiment]
Hereinafter, a communication system, a communication apparatus, and a communication method according to embodiments of the present invention will be described with reference to the drawings. In addition, here, it explains in order from analysis of a subject to a concrete solution means.

《Frequency division duplex and time division duplex》
FIG. 1 shows VDSL2 (ITU-T G.993.2) and G. It is a figure which shows contrast of the frequency band to be used with fast. In the figure, in VDSL2, communication is performed by frequency division duplex (FDD), and a frequency band of 1.1 MHz to 30 MHz is divided into “uplink” and “downlink” of communication. On the other hand, G. In the fast, communication is performed by time division duplex (TDD) using a frequency band from 1.1 MHz to 106 MHz.

<< Reference example of communication system >>
FIG. 2 shows G. It is a figure which shows the reference example of the communication system in which the communication system of fast and the communication system of VDSL2 which communicates by frequency division duplex are mixed. Such a communication system is provided in the housing complex 100, for example. This communication system uses metal lines 7, 8, and 9 for fixed telephones as communication lines. The collective devices 1, 2, and 3 as communication master units are installed in, for example, an electric room or a manager's room that is a common area in the collective housing 100. Each of the aggregation devices 1, 2, and 3 is connected to the upper network by, for example, an optical fiber. Here, the aggregation devices 1, 2, and 3 are different aggregation companies of communication services, for example, and are aggregation devices of A company, B company, and C company, respectively. Hereinafter, the collective devices 1, 2, and 3 are also referred to as A company CO (Central Office), B company CO, and C company CO, respectively, for convenience of explanation.

  On the other hand, in each house in the apartment house 100, home devices 4, 5, and 6 are provided as slave units. A device having an information communication function such as a personal computer is connected to the in-home devices 4, 5, 6. The in-home devices 4, 5, and 6 are, for example, different communication service providers, and are in-house devices of company A, company B, and company C, respectively. Hereinafter, the in-home devices 4, 5, and 6 are also referred to as A company CPE (Customer Premises Equipment), B company CPE, and C company CPE, respectively, for convenience of explanation. The A company CPE 4 is connected to the A company CO 1 via the metal line 7. The B company CPE 5 is connected to the B company CO 2 via the metal line 8. The C company CPE 6 is connected to the C company CO 3 via the metal line 9.

  Here, the communication system of A company that connects A company CO1 and A company CPE4 with metal line 7 is V. Fast and communicates in time division duplex. A communication system that connects the B company CO2 and the B company CPE5 with the metal line 8 and a communication system that connects the C company CO3 and the C company CPE6 with the metal line 9 are each VDSL2, and communicate by frequency division duplex.

The collective devices 1, 2, and 3 are not necessarily provided in one building of the collective housing 100 that is the same as the in-home devices 4, 5, and 6. For example, it may be provided in another building in the common site.
Further, FIG. 2 shows a state in which the parent device-child device of each company is connected in a one-to-one relationship for the sake of simplification. The machine has a one-to-many relationship.
Moreover, although three communication systems of A company, B company, and C company are illustrated as communication systems, this is only an example, and actually, a plurality of systems that are not limited to three can mutually connect metal lines. It exists in close proximity.

  The metal lines 7, 8, and 9 have a portion that is a bundle of wires 10 due to the structure of the apartment house 100. Therefore, the metal lines 7, 8, 9 of each communication system are close to each other to the extent that they may cause signal interference and cause communication interference.

  As described above, the metal line (7, 8 or 9) is connected between the collective device (1, 2 or 3) as the master unit and one or a plurality of home devices (4, 5 or 6) as the slave units. Assuming that one communication system communicates via the communication system, a plurality of systems are provided in the apartment house 100. The user of each house can freely select a communication service provider, and thus a situation occurs in which communication systems of a plurality of companies “coexist” in one such housing complex 100. Of course, for example, the communication system of Company A is a VDSL2 communication system and V. There may be a case where it is provided separately from the fast communication system. That is, for example, even when the collective devices 1, 2, and 3 in FIG.

  Here, if each communication system independently communicates without any restriction, for example, upstream transmission is performed from A company CPE4 to A company CO1, and A company CO1 is receiving. On the other hand, Company B always performs uplink / downlink communication. However, if attention is paid to downlink, downlink transmission is performed from Company B CO2 to Company B CPE5. In this case, the signal strength transmitted by the company B CO2 as the transmission source is large, and signal leakage may occur from the metal line 8 to the adjacent metal line 7. At this time, company A CO1 is receiving, and therefore may receive a leaked signal and cause communication interference. On the home side, the signal strength transmitted by the company A CPE 4 as the transmission source is large, and signal leakage occurs from the metal line 7 to the adjacent metal line 8. At this time, if the frequency of the leakage signal is within the range originally received by the B company CPE5, communication interference may occur.

FIG. 3 is a diagram showing signal leakage along with uplink / downlink signal transmission / reception on a transmission / reception time chart. Up and down signal transmission / reception is performed independently by company A and company B. In the communication system of Company A in FIG. 3, for example, when viewing the first frame from the left, a downstream signal is transmitted from Company A CO to Company A CPE. However, at this time, the upstream transmission signal (dotted line) of the B company CPE leaks to the A company CPE.
Further, when viewing the second frame from the left of the communication system of Company A, an upstream signal is transmitted from Company A CPE to Company A CO. However, at this time, the downstream transmission signal (dotted line) of Company B CO leaks to Company A CO.

When the third frame from the left of the communication system of Company A is viewed, a downstream signal is transmitted from Company A CO to Company A CPE. However, at this time, the upstream transmission signal (dotted line) of the B company CPE leaks to the A company CPE.
Further, when viewing the fourth frame from the left of the communication system of Company A, an upstream signal is transmitted from Company A CPE to Company A CO. However, at this time, the downstream transmission signal (dotted line) of Company B CO leaks to Company A CO.
If there is communication interference due to the leaked signal as described above, suppression of the signal that should be received occurs, which causes adverse effects such as deterioration in communication speed, leading to deterioration in communication quality.

<< Embodiments of Communication System, Communication Device, Transmission / Reception Method >>
FIG. 4 shows G. It is a figure which shows an example of the communication system with which the communication system of fast and two communication systems of VDSL2 which communicate by frequency division duplex are mixed. Such a communication system is provided in the housing complex 100, for example. This communication system uses metal lines 7, 8, and 9 for fixed telephones as communication lines. The collective devices 1, 2, and 3 as communication master units are installed in, for example, an electric room or a manager's room that is a common area in the collective housing 100. Each of the aggregation devices 1, 2, and 3 is connected to the upper network by, for example, an optical fiber. Here, the aggregation devices 1, 2, and 3 are different aggregation companies of communication services, for example, and are aggregation devices of A company, B company, and C company, respectively. Hereinafter, the collective devices 1, 2, and 3 are also referred to as A company CO (Central Office), B company CO, and C company CO, respectively, for convenience of explanation.

  On the other hand, in each house in the apartment house 100, home devices 4, 5, and 6 are provided as slave units. A device having an information communication function such as a personal computer is connected to the in-home devices 4, 5, 6. The in-home devices 4, 5, and 6 are, for example, different communication service providers, and are in-house devices of company A, company B, and company C, respectively. Hereinafter, the in-home devices 4, 5, and 6 are also referred to as A company CPE (Customer Premises Equipment), B company CPE, and C company CPE, respectively, for convenience of explanation. The A company CPE 4 is connected to the A company CO 1 via the metal line 7. The B company CPE 5 is connected to the B company CO 2 via the metal line 8. The C company CPE 6 is connected to the C company CO 3 via the metal line 9.

  Here, the communication system of A company that connects A company CO1 and A company CPE4 with metal line 7 is V. Fast and communicates in time division duplex. A communication system that connects the B company CO2 and the B company CPE5 with the metal line 8 and a communication system that connects the C company CO3 and the C company CPE6 with the metal line 9 are each VDSL2, and communicate by frequency division duplex.

Company A CO1 is connected to the metal line 7 via the variable high-pass filter 11. B company CO2 is connected to the metal line 8. Company C CO3 is connected to the metal line 9.
On the other hand, the APE CPE 4 is connected to the metal line 7 via the variable high-pass filter 14. The B company CPE 5 is connected to the metal line 8. The C company CPE 6 is connected to the metal line 9.

  The variable high-pass filters 11 and 14 can change the lower limit value of the passing frequency within a range of, for example, 1.1 MHz to 30 MHz. For example, as a simple example, the lower limit value can be changed stepwise, for example, 1.1 MHz, 17 MHz, and 30 MHz. Therefore, not only can the frequency of 1.1 to 106 [MHz], which is the entire frequency band of the time division duplex, be passed, but for example, the frequency of 17 to 106 [MHz] is mainly passed, or 30 to 106 [MHz]. MHz] can be passed. Of course, the lower limit value of the passage may be selected in more detail in multiple stages.

The collective devices 1, 2, and 3 are not necessarily provided in one building of the collective housing 100 that is the same as the in-home devices 4, 5, and 6. For example, it may be provided in another building in the common site.
In addition, FIG. 4 shows a state in which the parent device-child device of each company is connected in a one-to-one relationship for the sake of simplification. The machine has a one-to-many relationship.
Moreover, although three communication systems of A company, B company, and C company are illustrated as communication systems, this is only an example, and actually, a plurality of systems that are not limited to three can mutually connect metal lines. It exists in close proximity.

  The metal lines 7, 8, and 9 have a portion that is a bundle of wires 10 due to the structure of the apartment house 100. Therefore, the metal lines 7, 8, 9 of each communication system are close to each other to the extent that they may cause signal interference and cause communication interference.

  5 shows VDSL2 and band-limited G.264. It is a figure which shows contrast of the frequency band to be used with fast. In the figure, in VDSL2, communication is performed by frequency division duplex (FDD), and a frequency band of 1.1 MHz to 30 MHz is divided into “uplink” and “downlink” of communication. On the other hand, G. In fast, it is possible to perform time division duplex (TDD) communication using a frequency band from 1.1 MHz to 106 MHz, but a signal to be originally communicated is assigned to a frequency band from 30 MHz to 106 MHz, and 30 MHz or more. The frequency band of 1.1 MHz to 30 MHz competing with the frequency division duplex communication system can be subjected to substantial band limitation.

  FIG. 6 is a circuit block diagram showing an outline of transmission / reception of a collective device or a home device (hereinafter, representatively referred to as a communication device). In the figure, the communication device 20 first inserts dummy data into the input frame to be transmitted in the dummy data processing unit 20a. The signal with the dummy data inserted is then encoded by the data encoder 20b and subjected to OFDM (Orthogonal Frequency Division Multiplexing) modulation, which is a typical example of multi-charier modulation, in the modulation unit 20c. The The modulated signal is transmitted to the communication partner via the hybrid 20d.

Conversely, the signal received from the communication partner is demodulated by the demodulator 20e via the hybrid 20d. The demodulated data is decoded by the data decoder 20f, the dummy data processing unit 20a excludes the dummy data, and becomes an output frame.
As described above, when a signal to which dummy data is assigned is received from a communication partner, dummy data on a predetermined subcarrier is excluded. As a result, dummy data remaining while being attenuated through the variable high-pass filters 11 and 14 or unnecessary mixed data received while being attenuated by the variable high-pass filters 11 and 14 are completely excluded on the receiving side. be able to.

<< Specific examples of circuit configuration >>
FIG. 7 is a block diagram illustrating processing on the transmission side of the basic communication unit 20 </ b> A and the like in the communication device 20. However, this is a block diagram showing a flow of generating an OFDM signal (multicarrier wave) from original serial bit data without inserting dummy data for comparison. The basic communication unit 20A includes a block diagram (FIG. 8) for performing processing on the receiving side. Further, both the parent device (Company A CO1) and the child device (Company A CPE4) have basically the same transmission / reception functions.

  In the figure, if the data input from the signal generation unit 201 is, for example, “D1, D2, D3, D4, D5, D6,...”, The serial-parallel converter 202 first distributes the data from serial to parallel data. Is converted as follows. The data distributed in parallel is input to the respective subcarrier modulators 203-1, 203-2, 203-3,..., 203-n, and becomes modulated data for each subcarrier. Each subcarrier modulator corresponds to a frequency band from 1.1 MHz to 106 MHz, and the actual number is very large (for example, about 2000), but here, it is shown in a simplified manner for convenience of illustration. . For example, it is assumed that the subcarrier modulator 203-1 (actually plural) has a subcarrier frequency within a range from 1.1 MHz to 30 MHz. Therefore, the remaining subcarrier modulators 203-2, 203-3,..., 203-n are subcarriers having frequencies in the range from 30 MHz to 106 MHz.

  The outputs of the subcarrier modulators 203-1, 203-2, 203-3,..., 203-n are input to the inverse Fourier modulator 204 and converted from frequency domain data to time domain data. Then, it is converted into serial data by the parallel-serial converter 205 and output as an OFDM signal. The serial-parallel converter 202, the subcarrier modulators 203-1, 203-2, 203-3,..., 203-n, the inverse Fourier transformer 204, and the parallel-serial converter 205 are included in the multicarrier modulator 20m. Is configured.

  FIG. 8 is a block diagram showing processing on the receiving side of the basic communication unit 20A and the like. However, this is a block diagram showing a flow of original demodulation processing from an OFDM signal without inserting dummy data for comparison. As described above, the basic communication unit 20A includes a block diagram (FIG. 7) for performing processing on the transmission side.

  In the figure, the OFDM signal is converted into parallel data by a serial-parallel converter 206. The converted data is converted from the time domain to the frequency domain by the fast Fourier transformer 207. The converted data is demodulated by subcarrier demodulators 208-1, 208-2, 208-3,..., 208-n for each subcarrier. The demodulated signal is converted into serial data by a parallel / serial converter 209. The signal acquisition unit 210 acquires this data. The serial-parallel converter 206, the fast Fourier transformer 207, the subcarrier demodulators 208-1, 208-2, 208-3,..., 208-n, and the parallel-serial converter 209 are included in the multicarrier demodulator 20d. Is configured.

  Next, FIG. 9 is a block showing processing on the transmission side including the band limiting unit 20B in the communication apparatus 20, and a block showing a flow of generating an OFDM signal when processing for inserting dummy data is performed. FIG. The basic communication unit 20A (FIG. 7) described above is also a state in which the function of the band limiting unit 20B (FIG. 9) is omitted. If the function of the band limiting unit 20B is deactivated, the circuit function is equivalent to that shown in FIG. The communication device 20 includes a block diagram (FIG. 10) that performs processing on the receiving side. Further, both the parent device (Company A CO1) and the child device (Company A CPE4) have basically the same transmission / reception functions.

  As is clear from comparison with FIG. 7, a band limiting unit 20B is provided in FIG. Inside and outside the band limiting unit 20B, a band information determining unit 211, a dummy data insertion control unit 212, a dummy data insertion unit 213, and a dummy data generation unit 214 are provided. The dummy data insertion control unit 212, the dummy data insertion unit 213, and the dummy data generation unit 214 constitute a band limiting unit 20B. The variable high-pass filter 11 or 14 is also a part of the band limiting unit 20B. Other configurations are the same as those in FIG. The dummy data generation unit 214 generates dummy data that is meaningless as a signal. The dummy data is, for example, “Dd, Dd, Dd, Dd,. In response to an instruction from the dummy data insertion control unit 212, the dummy data insertion unit 213 performs an operation of inserting or not inserting dummy data into the original communication signal generated by the signal generation unit 201.

  Assume that the transmission-side circuit shown in FIG. Therefore, the slave (A company CPE4) is the communication partner. The band information determination unit 211 determines band information to be used from, for example, error detection information received from the slave unit immediately before. The error detection information is transmitted, for example, embedded in a payload. Here, if there is no error detection, the band information determination unit 211 determines that there is no communication interference due to signal leakage from other communication systems of frequency division duplex, and determines that band limitation is unnecessary.

  In this case, the bandwidth information determination unit 211 issues an instruction not to limit the bandwidth to the dummy data insertion control unit 212, and the dummy data insertion control unit 212 that has received the instruction instructs the dummy data insertion unit 213 to perform dummy processing. Instructs not to insert data. Therefore, the dummy data insertion unit 213 passes the data sent from the signal generation unit 201 as it is without accepting the dummy data, and outputs the data to the serial-parallel converter 202. Further, the band information determination unit 211 gives an instruction to the variable high-pass filter 11 to pass the lower limit value of the pass band at 1.1 MHz, that is, without filtering. Accordingly, the band limiting unit 20B at this time is substantially not present, and only the signal generation unit 201 and the basic communication unit 20A operate.

  On the other hand, if there is an error detection on the receiving side and the band information determination unit 211 in FIG. 9 determines that band limitation is required, the band information determination unit 211 sends dummy data to the dummy data insertion control unit 212. Give instructions to insert. In response to this, the dummy data insertion control unit 212 causes the dummy data insertion unit 213 to insert dummy data. Further, the band information determination unit 211 causes the variable high-pass filter 11 to exhibit a filter function that suppresses passage of a frequency band of 1.1 MHz to 30 MHz, for example, as an easy-to-understand example.

  Also, the dummy data insertion unit 213 has a certain regularity so that the inserted dummy data is assigned to, for example, the subcarrier modulators 203-1 (actually plural) in charge of 1.1 MHz to 30 MHz. insert. When the serial-to-parallel converter 202 distributes data from serial to parallel data, all dummy data is assigned to the subcarrier modulator 203-1. Further, data “D1, D2, D3, D4,...” To be originally communicated is assigned to other subcarrier modulators 203-2, 203-3,.

  The outputs of the subcarrier modulators 203-1, 203-2, 203-3,..., 203-n are input to the inverse Fourier transformer 204 and converted from frequency domain data to time domain data. Then, it is converted into serial data by the parallel-serial converter 205 and output as an OFDM signal. This output includes dummy data on subcarriers in the range of 1.1 MHz to 30 MHz. Therefore, the variable high-pass filter 11 suppresses the frequency band from 1.1 MHz to 30 MHz. Therefore, even if the signal in the frequency band from 1.1 MHz to 30 MHz is output on the metal line 7, it is greatly attenuated.

  The frequency of the signal transmitted to the metal line by assigning dummy data to some subcarriers (within a range of 1.1 MHz to 30 MHz) of multicarrier modulation and filtering by the variable high-pass filter 11 as described above. It is possible to limit the bandwidth.

  Next, FIG. 10 is a block diagram illustrating a process on the reception side in the communication apparatus 20 and a flow of a demodulation process from an OFDM signal when performing a process of excluding dummy data. In this circuit configuration, a dummy data excluding unit 215, a dummy data excluding control unit 216, and a variable high-pass filter 14 (or 11) are provided in addition to the basic communication unit 20A on the receiving side. In other words, if these additional functions are deactivated, the circuit function can be used as the basic communication unit 20A in FIG.

Assume that the circuit on the reception side shown in FIG. 10 is on the side of the slave (A company CPE4), for example. Therefore, the communication partner is the parent machine (Company A CO1).
In FIG. 10, the signal acquisition unit 210 includes a band information acquisition unit 210a, an error detection unit 210b, and an S / N ratio detection unit 210c. It can also be said that the error detection unit 210b and the S / N ratio detection unit 210c constitute a leakage determination unit 210d. The variable high-pass filter 14 is also a part of the band limiting unit 20B. Other configurations are the same as those in FIG.

  In response to an instruction from the dummy data exclusion control unit 216, the dummy data exclusion unit 215 excludes dummy data from the demodulated signal. The instruction is “band information” indicating which range of subcarriers the dummy data is on, and which range of subcarriers the original communication signal is on. The band information is embedded in the payload of the communication signal on the transmission side, for example. The band information acquisition unit 210a gives the band information to the dummy data exclusion control unit 216 and the variable high-pass filter 14. The error detection unit 210b detects an error in the received signal. The S / N ratio detection unit 210c detects the S / N ratio (signal-to-noise ratio) of the received signal.

  Referring to FIG. 10, assuming that the received signal is obtained in a desired form with band limitation, the OFDM signal passes through the variable high-pass filter 14 and is converted into parallel data by the serial-parallel converter 206. Converted. The converted data is converted from the time domain to the frequency domain by the fast Fourier transformer 207. The converted data is demodulated by subcarrier demodulators 208-1, 208-2, 208-3,..., 208-n for each subcarrier. The output of subcarrier demodulator 208-1 (actually plural) in charge of 1.1 MHz to 30 MHz is dummy data. The demodulated signal is converted into serial data by a parallel / serial converter 209. This data includes dummy data with a certain regularity. Therefore, the dummy data excluding unit 215 excludes dummy data. In this way, only data that should be communicated is output.

  Next, although the order is reversed, a process until a desired reception state as described above is obtained will be described. First, for example, it is assumed that a signal is transmitted without band limitation. In this case, the band information acquisition unit 210a does not include dummy data, and “band information” indicating that signals to be communicated are distributed on subcarriers in all frequency bands (1.1 MHz to 106 MHz). get.

  On the other hand, since the error detection unit 210b is expected to cause communication interference due to a leaked signal when an error is detected even though the S / N ratio is good, the transmission function of the slave unit Provides error detection information to the base unit. Upon receiving this, the base unit puts dummy data on subcarriers in the range of 1.1 MHz to 30 MHz, and puts data to be originally communicated on all other subcarriers. This “band information” is, for example, embedded in the payload and reported from the parent device to the child device. The band information acquisition unit 210a in FIG. 10 issues an instruction to the dummy data exclusion control unit 216 based on this band information, and the dummy data exclusion unit 215 excludes the dummy data demodulated by the subcarrier demodulator 208-1. Thereby, a necessary communication signal can be received from the data demodulated by the other subcarrier demodulators 208-2, 208-3,..., 208-n. In this case, the error detection unit 210b does not detect an error.

In the above description, as an easy-to-understand example, an example in which band limitation is suddenly performed in the entire range from 1.1 MHz to 30 MHz is shown, but in reality, it is not known at first how much band limitation is appropriate. Therefore, the upper limit value of the frequency to be band-limited can be gradually increased from a small value close to 1.1 MHz so as to gradually approach 30 MHz according to the error detection result. For example, if band limitation is applied in two stages, dummy data is placed on subcarriers in the range of 1.1 MHz to 16 MHz for the time being, and data to be originally communicated is placed on all other subcarriers. If there is still error detection, dummy data is placed on all subcarriers of 1.1 MHz to 30 MHz, and data to be originally communicated is placed on all other subcarriers. Of course, the number of levels is not limited to two, and the number of levels may be further reduced.
In addition, the lower limit of the range to be limited is not limited to 1.1 MHz, and the upper limit is not limited to 30 MHz. Depending on the actual situation in the field, the required frequency range may be arbitrarily limited partially. Good.

  FIG. 11 is a diagram illustrating subcarriers of an OFDM signal. For example, there exists subcarrier 1 having the highest frequency, such as subcarrier 1 having the lowest frequency, subcarrier 2, subcarrier 3, and the like. If the dummy data is assigned to the subcarrier 1, the signal of this subcarrier carrying the dummy data falls outside the pass band (above 30 MHz) of the variable high-pass filter (11 or 14), so that it is greatly attenuated and the metal line 7 Going out in is suppressed.

  Further, dummy data may be assigned to subcarrier 2 and subcarrier 3. In this case, the dummy data assigned to the subcarrier 2 and the subcarrier 3 goes out to some extent on the metal line 7, but the frequency of the subcarrier 3 is higher than 30 MHz and is almost not used in a frequency division duplex communication system. Does not affect. Although there is a possibility that the subcarrier 2 has an influence, since the signal level is attenuated, in practice, the leakage becomes weak and does not substantially influence.

As described above, by inserting dummy data, it is possible to easily limit the frequency band effectively by combining with a filter without changing the modulation method itself of multicarrier modulation in OFDM. Moreover, since the data to be originally communicated is allocated to subcarriers other than the subcarrier to which dummy data is allocated, communication contents are not lost.
However, when the level of a leaked signal coming from another communication system is low and there is no possibility of interference, dummy data is not inserted and all frequency bands (1.1 MHz to 106 MHz) can be used for communication. .

<Summary>
As described above, in the communication system of this embodiment, first, there are a plurality of communication systems that communicate via a metal line between a master unit and a slave unit, and the metal lines of each communication system are close to each other. The communication system is used in a communication system of time division duplex that can coexist with the communication system of frequency division duplex. The time division duplex communication system partially overlaps a first frequency band (eg, 1.1 MHz to 30 MHz) used in frequency division duplex, and a second frequency band (which is wider than the first frequency band ( (E.g., 1.1 MHz to 106 MHz), and communication interference in the first frequency band between the basic communication unit 20 </ b> A that communicates using a signal subjected to multicarrier modulation and a communication system of frequency division duplex When transmission is expected, dummy data is allocated to subcarriers in the first frequency band range, data to be originally communicated is allocated to other subcarriers, and the subcarrier on which the dummy data is placed is allocated. It can also be said that the communication system includes a band limiting unit that suppresses a signal from going out on a metal line by a filter.

In such a communication system, modulation is performed in which dummy data is allocated to subcarriers in the first frequency band in which communication interference is expected, and the subcarrier carrying the dummy data is suppressed by a filter. Since transmission to the metal line is suppressed, it is possible to prevent communication interference between adjacent metal lines. In addition, since the data to be originally communicated in the second communication system is assigned to other subcarriers, the communication content is not lost.
In this way, it is possible to prevent communication interference between metal lines of communication systems in which usable frequency bands are partially overlapped by a simple method, and to prevent deterioration in communication quality.

  Further, the “communication device” which is a collective device or a home device is a communication device as a parent device or a child device that constitutes a communication system that communicates between a parent device and a child device via a metal line. The basic communication unit 20A includes a frequency of the first frequency band that can be used in other communication systems, and uses a second frequency band wider than that, and is time-division duplex and multi-carrier modulation. It is possible to communicate with the signal subjected to. Further, as the band limiting unit 20B, when interference of communication in the first frequency band is expected with another communication system, dummy data is allocated to subcarriers in the first frequency band range, Data to be originally communicated is assigned to the other subcarriers, and a filter suppresses the subcarrier signal carrying the dummy data from going out on the metal line.

  Also, from the viewpoint of the transmission method, it is a transmission method in the case of communication between the master unit and the slave unit via a metal line, from another communication system communicating by frequency division duplex to its own communication system. When the leaked signal is received and the frequency band used for frequency division duplex is the first frequency band, it is determined whether or not it is necessary to limit the band of at least a part of the first frequency band. When band limitation is not required, a signal that overlaps with the first frequency band and is time-division duplexed and multi-carrier modulated using a second frequency band wider than the first frequency band. If the bandwidth limit is required, dummy data is allocated to the necessary subcarriers in the first frequency band range, and data to be originally communicated is allocated to the other subcarriers for transmission. , Said da Subcarrier signals Deta rode suppressing by filtering the outgoing on said metal line is a transmission method.

  Furthermore, from the viewpoint of the reception method, it is a reception method when communication is performed between the master unit and the slave unit via a metal line, and dummy data is transmitted to subcarriers in a frequency band used by frequency division duplex communication. Is received, and when the signal to which data to be originally communicated is assigned is received, the dummy data is excluded after demodulation.

  From the viewpoint of the communication method (transmission / reception method), it is a communication method in which communication is performed between the parent device and the child device via a metal line, and communication is performed from another communication system that performs communication by frequency division duplex. If a signal leaked to the system is received and the frequency band used in frequency division duplex is the first frequency band, it is determined whether or not at least a part of the first frequency band needs to be band-limited. If band limitation is not required, time division duplex and multi-carrier modulation is performed using a second frequency band that partially overlaps the first frequency band and is wider than the first frequency band. If the bandwidth is limited, dummy data is allocated to the necessary subcarriers within the first frequency band range, and data to be originally communicated is allocated to the other subcarriers for transmission. As well as The filter suppresses the subcarrier signal carrying the dummy data from going out on the metal line. On the other hand, when a signal to which dummy data is assigned is received from the communication partner, the dummy data is demodulated. It is a communication method that excludes.

  Note that the band limiting unit 20B in the communication apparatus as described above is, for example, that a plurality of communication systems in the future are all G.D. If it is fast, that function is unnecessary. However, even in such a case, it is sufficient to operate as the basic communication unit 20A that kills functions such as insertion / exclusion of dummy data that is no longer necessary, so that the communication device can be used without any problem.

  In addition, although VDSL2 was illustrated and demonstrated as a 1st communication system, it is the same also not only in VDSL2 but other conventional DSL systems (for example, VDSL, ADSL).

《Supplementary Note》
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, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Aggregation device / Company A CO
2 Aggregation device / Company B CO
3 Aggregator / C Company CO
4 In-home device / Company A CPE
5 In-home equipment / Company B CPE
6 In-home equipment / C company CPE
7, 8, 9 Metal line 10 Bundle 11 Variable high-pass filter 14 Variable high-pass filter 20 Communication device 20A Basic communication unit 20B Band limiting unit 20a Dummy data processing unit 20b Data encoder 20c Modulation unit 20d Hybrid 20e Demodulation unit 20f Data decoder 100 Collective housing DESCRIPTION OF SYMBOLS 201 Signal generation part 202 Serial-parallel converter 203-1, 203-2, 203-3, ..., 203-n Subcarrier modulator 204 Inverse Fourier transformer 205 Parallel-serial converter 206 Serial-parallel converter 207 Fast Fourier Converters 208-1, 208-2, 208-3,..., 208-n Subcarrier demodulator 209 Parallel-serial converter 210 Signal acquisition unit 210a Band information acquisition unit 210b Error detection unit 210c S / N ratio detection unit 210d Leakage determination unit 211 Band information Tough 212 dummy data insertion control unit 213 dummy data inserting section 214 dummy data generating unit 215 dummy data elimination unit 216 dummy data exclusion controller

Claims (8)

A communication system used for a communication system in which a plurality of communication systems communicate via a metal line between a parent device and a child device, and the metal lines of each communication system are close to each other,
It is used for a time division duplex communication system that can coexist with a frequency division duplex communication system.
The communication system of the time division duplex is
A basic communication unit that communicates with a signal subjected to multicarrier modulation using a second frequency band that partially overlaps the first frequency band used in the frequency division duplex and wider than the first frequency band When,
Assigning dummy data to subcarriers within the range of the first frequency band at the time of transmission when communication interference in the first frequency band is expected with the frequency division duplex communication system; A bandwidth limiting unit that assigns data to be originally communicated to other subcarriers and suppresses the subcarrier signal carrying the dummy data from going out on the metal line by a filter,
A communication system. When receiving a signal from a communication partner, after demodulation, a band information acquisition unit that acquires band information related to frequency band allocation;
A dummy data excluding unit that excludes dummy data from the demodulated signal when there is a subcarrier to which dummy data is assigned based on the band information;
The communication system according to claim 1, comprising:   The communication system according to claim 1, wherein the filter is provided at least on the parent device side of the parent device and the child device when the communication interference is expected. A communication device as the master unit or slave unit that constitutes a communication system that communicates between a master unit and a slave unit via a metal line,
A signal that is partly overlapped with a first frequency band that can be used in another communication system, and that has been subjected to time division duplex and multi-carrier modulation using a second frequency band that is wider than the first frequency band. A basic communication unit communicating with
At the time of transmission when communication interference in the first frequency band is expected with the other communication system, dummy data is allocated to subcarriers within the range of the first frequency band, and other sub-carriers are transmitted. A band limiting unit that assigns data to be originally communicated to a carrier and suppresses a signal of a subcarrier carrying the dummy data from going out on the metal line by a filter;
A communication device comprising:   A leakage determination unit that detects signal leakage from another communication system based on a demodulated signal at the time of reception, a subcarrier to which the dummy data is allocated and data that should be originally communicated at the time of transmission based on the signal leakage The communication apparatus according to claim 4, further comprising: a band information determination unit that determines a subcarrier to which to allocate a subcarrier. A transmission method for communication between a parent device and a child device via a metal line,
Receives signals leaking from other communication systems communicating with frequency division duplex to its own communication system,
When the frequency band used in the frequency division duplex is the first frequency band, it is determined whether it is necessary to band limit at least a part of the first frequency band,
When band limitation is not required, time division duplex and multi-carrier modulation are performed using a second frequency band that partially overlaps the first frequency band and is wider than the first frequency band. Send by signal,
When band limitation is required, dummy data is allocated to necessary subcarriers within the first frequency band, and data to be originally communicated is allocated to other subcarriers for transmission, and the dummy data is transmitted. A transmission method, wherein a filter suppresses a signal of a subcarrier carrying data from going out on the metal line. It is a receiving method when communicating between a master unit and a slave unit via a metal line,
When dummy data is assigned to subcarriers in a frequency band used for frequency division duplex communication and signals to which data to be originally communicated are assigned to other subcarriers, the dummy data is demodulated after demodulation. Receiving method that excludes. A communication method for communicating between a master unit and a slave unit via a metal line,
Receives signals leaking from other communication systems communicating with frequency division duplex to its own communication system,
When the frequency band used in the frequency division duplex is the first frequency band, it is determined whether it is necessary to band limit at least a part of the first frequency band,
When band limitation is not required, time division duplex and multi-carrier modulation are performed using a second frequency band that partially overlaps the first frequency band and is wider than the first frequency band. Send by signal,
When band limitation is required, dummy data is allocated to necessary subcarriers within the first frequency band, and data to be originally communicated is allocated to other subcarriers for transmission, and the dummy data is transmitted. The filter suppresses the signal of the subcarrier carrying the data from going out on the metal line,
A communication method in which, when a signal to which the dummy data is assigned is received from a communication partner, the dummy data is excluded after demodulation.