JP2018019242A - Coaxial communication system, pon system, station side device, and band limiting method - Google Patents

Abstract

An RF signal based on a PON signal is appropriately superimposed on a coaxial cable. The present invention relates to a coaxial communication system using a coaxial cable as a transmission path, and a first coaxial cable that is a transmission path of a first RF signal transmitted by a coaxial communication device, and a plurality of communication paths that respectively communicate with a plurality of user homes. The second coaxial cable, a distributor for distributing the first RF signal to the plurality of second coaxial cables, and a station side device via a PON line, and converting the second RF signal converted from the PON signal to the second A housing-side device for an apartment house superimposed on a coaxial cable. [Selection] Figure 4

Description

  The present invention relates to a coaxial communication system, a PON system, a station side device constituting the PON system, and a band limiting method executed by the station side device.

Patent Document 1 describes a coaxial communication system using a coaxial cable as a transmission path. A coaxial communication system employs a wiring structure in which a coaxial cable that transmits an RF (Radio Frequency) signal is distributed to each room in a house by a distributor.
The signal level of the RF signal decreases due to signal loss in the coaxial cable or signal attenuation when passing through the distributor. In this case, the RF signal is amplified by performing a construction for arranging a booster in the middle of the coaxial cable.

JP 2012-119743 A

By the way, if a relatively high frequency band RF signal generated by converting a PON signal is superimposed on a coaxial cable of an existing coaxial communication system, communication in a plurality of types of frequency bands is possible with one coaxial communication system. Become.
However, when the RF signal based on the PON signal is superimposed on the main line side of the distributor, the superimposed RF signal is attenuated by the distributor, and there is a possibility that an RF signal having sufficient signal strength does not reach each room. Therefore, a technique capable of appropriately superimposing the RF signal based on the PON signal on the coaxial cable is desired.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a coaxial communication system or the like that can appropriately superimpose an RF signal based on a PON signal on a coaxial cable.

  (1) A system according to an aspect of the present invention is a coaxial communication system using a coaxial cable as a transmission path, and includes a first coaxial cable that is a transmission path of a first RF signal transmitted by the coaxial communication device, and a plurality of users. A plurality of second coaxial cables respectively leading to the home, a distributor for distributing the first RF signal to the plurality of second coaxial cables, and a second RF converted from the PON signal by communicating with the station side device via the PON line A housing-side device for an apartment house that superimposes a signal on the second coaxial cable.

  (6) A system according to another aspect of the present invention is connected to a station-side device connected to a PON line, and the PON line and a coaxial cable of a coaxial communication system, and mutually converts a PON signal and an RF signal. A plurality of home-side devices having a function, and an information acquisition unit used for bandwidth limitation of communication by the second RF signal, the station-side device based on the information notified from the acquisition unit The communication band is limited by the RF signal.

  (7) An apparatus according to an aspect of the present invention is a station-side apparatus that communicates with a home-side apparatus connected to a PON line and a coaxial cable of a coaxial communication system, and uses information used for bandwidth limitation of communication by an RF signal. Based on the received information, bandwidth limitation of communication by the RF signal is executed.

  (8) A method according to an aspect of the present invention is a band limiting method executed by a station-side device that communicates with a home-side device connected to a PON line and a coaxial cable of a coaxial communication system. Receiving information used for bandwidth limitation, and executing bandwidth limitation of communication using the RF signal based on the received information.

The present invention can be realized not only as a system and apparatus having the above-described characteristic configuration, but also as a program for causing a computer to execute such characteristic configuration.
Further, the present invention can be realized as a semiconductor integrated circuit that realizes part or all of the system and apparatus.

  According to the present invention, an RF signal based on a PON signal can be appropriately superimposed on a coaxial cable.

1 is a schematic diagram of a PON system according to an embodiment of the present invention. It is a block diagram which shows an example of an internal structure of OLT and ONU. It is a block diagram which shows an example of an internal structure of a coaxial adapter. It is a block diagram which shows an example of the wiring structure of the coaxial communication system laid in the apartment house. It is a sequence diagram which shows an example of the zone | band limitation by OLT. It is a sequence diagram which shows another example of the band limitation by OLT. It is a sequence diagram which shows another example of the band limitation by OLT.

<Outline of Embodiment of the Present Invention>
Hereinafter, an outline of embodiments of the present invention will be listed and described.

  (1) A coaxial communication system according to an aspect of the present invention is a coaxial communication system using a coaxial cable as a transmission path, and includes a first coaxial cable that is a transmission path of a first RF signal transmitted by the coaxial communication device, and a plurality of coaxial communication systems. A plurality of second coaxial cables respectively leading to the user's home, a distributor for distributing the first RF signal to the plurality of second coaxial cables, and a station side device via a PON line, and converted from the PON signal A housing-side device for an apartment house that superimposes a second RF signal on the second coaxial cable.

According to the coaxial communication system of the present embodiment, the housing side device (ONU) for an apartment house communicating with the station side device (OLT) via the PON line converts the second RF signal converted from the PON signal into the distributor. Superimpose on the second coaxial cable on the branch line side.
For this reason, the superimposed second RF signal reaches the user's home without being attenuated by the distributor. Therefore, the second RF signal based on the PON signal can be appropriately superimposed on the coaxial cable.

(2) In the coaxial communication system according to the present embodiment, in the case of further including an acquisition unit that acquires information used for bandwidth limitation of communication using the second RF signal, the home device is notified from the acquisition unit It is preferable to have a management control unit that performs bandwidth limitation of communication using the second RF signal based on the information.
In this case, since the management control unit of the home side device executes the bandwidth limitation of the communication by the second RF signal, even when the second RF signal is superimposed on the coaxial cable with poor quality, the communication bandwidth by the second RF signal is appropriately set. Can be adjusted.
(3) In the coaxial communication system according to the present embodiment, in the case of further including an acquisition unit that acquires information used for bandwidth limitation of communication by the second RF signal, the station-side device is notified from the acquisition unit It is preferable to have a management control unit that performs bandwidth limitation of communication using the second RF signal based on the information.
In this case, since the management control unit of the station side device executes the bandwidth limitation of the communication by the second RF signal, even when the second RF signal is superimposed on the coaxial cable having a poor quality, the communication bandwidth by the second RF signal is appropriately set. Can be adjusted.

(4) In the coaxial communication system of the present embodiment, it is preferable that the bandwidth limitation of communication by the second RF signal is a bandwidth limitation that is fair to the plurality of user homes.
In this way, it is possible to prevent the occurrence of unfairness associated with the difference in the maximum communication band depending on the user's home.

(5) In the coaxial communication system of the present embodiment, the acquisition unit includes an external device that receives an input of the information by an administrator, and the external device notifies the management control unit of the input information. Is preferred.
In this way, by inputting information to the external device, it is possible to easily limit the bandwidth of communication using the second RF signal.

  (6) The PON system of this embodiment is connected to a station side device connected to a PON line, and to the PON line and a coaxial cable of a coaxial communication system, and has a function of mutually converting a PON signal and an RF signal. A plurality of home-side devices and an information acquisition unit used for bandwidth limitation of communication using the RF signal, and the station-side device uses the RF signal based on the information notified from the acquisition unit. Performs communication bandwidth limitation by.

  According to the PON system of the present embodiment, since the station side device performs bandwidth limitation of communication using the RF signal based on the information notified from the acquisition unit, it is necessary to provide a buffer for bandwidth limitation in the home side device. And the equipment cost of the entire system can be reduced.

(7) The station-side device of the present embodiment is a station-side device that communicates with a home-side device connected to a PON line and a coaxial cable of a coaxial communication system, and receives information used for band limitation of communication using an RF signal. Then, based on the received information, the band limitation of communication by the RF signal is executed.
According to the station-side apparatus of the present embodiment, the station-side apparatus receives information used for band limitation of communication using an RF signal, and executes band limitation of communication using an RF signal based on the received information. It is no longer necessary to provide a buffer for the home-side apparatus, and the equipment cost of the entire system can be suppressed.

(9) The band limiting method of the present embodiment is a band limiting method executed by a station side device that communicates with a home side device connected to a PON line and a coaxial cable of a coaxial communication system, and is a communication band based on an RF signal. Receiving information used for restriction, and executing bandwidth restriction of communication using the RF signal based on the received information.
According to the band limiting method of the present embodiment, the station side device receives information used for band limitation of communication using an RF signal, and executes band limitation of communication using an RF signal based on the received information. It is not necessary to provide a buffer for restriction in the home device, and the equipment cost of the entire system can be suppressed.

<Details of Embodiment of the Present Invention>
Hereinafter, details of embodiments of the present invention will be described with reference to the drawings. In addition, you may combine arbitrarily at least one part of embodiment described below.

[Overall configuration of PON system]
FIG. 1 is a schematic diagram of a PON system 10 according to an embodiment of the present invention.
As shown in FIG. 1, the PON system 10 of this embodiment includes a station side device (OLT: Optical Line Terminal) 11, a plurality of home side devices (ONU: Optical Network Unit) 12, and a PON line 13. .

A user terminal (not shown) capable of Ethernet (“Ethernet” is a registered trademark) can be connected to the UNI port 34 (see FIG. 2) of the ONU 12. The number and type of user terminals connected to the ONU 12 are not particularly limited. It is not essential to connect the user terminal directly to the ONU 12.
A user network (not shown) may be connected to the ONU 12. The user terminal may be connected to the ONU 12 via the user network.

The PON line 13 is an optical communication line including an optical splitter 14 and optical fibers 15 and 16. The PON line 13 includes one trunk optical fiber 15 and a plurality of branch optical fibers 16. Each optical fiber 15 and 16 is connected to the optical splitter 14.
The optical signal transmitted from the OLT 11 is branched by the optical splitter 14 through the trunk optical fiber 15 of the PON line 13. The branched optical signal is transmitted to each ONU 12 through the branch optical fiber 16.

The optical signal transmitted from each ONU 12 passes through the branch optical fiber 16 and is focused by the optical splitter 14. The focused optical signal is transmitted to the OLT 11 through the trunk optical fiber 15.
The optical splitter 14 used for the PON line 13 does not particularly require external power supply, and passively branches or multiplexes the optical signal from the input optical signal.

The upstream optical signals transmitted to the branch line optical fiber 16 merge at the optical splitter 14. Therefore, multiplexing is necessary so that optical signals of the same wavelength do not collide after joining.
In the PON system 10, time division multiplexing is performed in accordance with MPCP (Multi-Point Control Protocol). Specifically, the OLT 11 calculates the transmission start time and the transmission permission amount in the uplink direction of the data accumulated in the ONU 12 based on the control frame (report) transmitted from each ONU 12.

Next, the OLT 11 transmits the control frame (grant) in which the instruction signal is inserted to each ONU 12 via the PON line 13. Each ONU 12 notifies the OLT 11 with a report of the length of data in its own buffer at the time designated by the grant.
Each ONU 12 receives the grant in which the instruction signal is inserted from the OLT 11. Based on the instruction signal, each ONU 12 transmits the data in its own buffer to the OLT 11 together with the report.

  In addition, the OLT 11 detects the ONU 12 of the PON line 13 by executing a discovery process. Further, the OLT 11 executes a registration process for registering the detected ONU 12 in the OLT 11.

[Internal configuration of OLT and ONU]
FIG. 2 is a block diagram illustrating an example of an internal configuration of the OLT 11 and the ONU 12.
As shown in FIG. 2, the OLT 11 includes an optical transceiver 21, a PON processing unit 22, an L2 switch 23, and a management control unit (CPU) 24.

The optical transceiver 21 is an optical device including a circuit for transmitting and receiving an optical signal. The optical transceiver 21 is optically connected to the trunk optical fiber 15 (see FIG. 1) and is electrically connected to the PON processing unit 22.
The optical transceiver 21 mutually converts an optical signal and an electric signal. That is, the optical transceiver 21 converts an upstream signal composed of an optical signal from the ONU 12 into an electrical signal. The optical transceiver 21 converts the electrical signal from the PON processing unit 22 into an optical signal.

The PON processing unit 22 includes an integrated circuit that executes predetermined communication processing in accordance with the PON communication standard.
When the upstream signal is a control frame (report) from the ONU 12, the PON processing unit 22 determines the upstream transmission start time and transmission permission amount for the ONU 12, and notifies the ONU 12 of the control frame (grant). . The PON processing unit 22 also executes the above-described discovery process and registration process.

The PON processing unit 22 transmits the frame to the L2 switch 23 when the frame included in the uplink signal is a data frame to the upper network.
When the frame included in the downstream signal is a data frame for the ONU 12, the PON processing unit 22 causes the optical transceiver 21 to transmit the frame.

The L2 switch 23 includes an integrated circuit that determines a transmission port according to the destination of the received L2 layer frame.
The L2 switch 23 transmits the frame to the PON processing unit 22 when the frame included in the downlink signal from the upper network is addressed to the MAC processing unit 33.

When the frame included in the upstream signal from the PON processing unit 22 is a data frame to the upper network, the L2 switch 23 transmits the frame to the upper network.
When the frame included in the upstream signal from the PON processing unit 22 is a management frame addressed to the management control unit 24, the L2 switch 23 transmits the frame to the frame management control unit 24.

The L2 switch 23 can change the QoS (Quality of Survice) parameter of the downlink signal for each MAC processing unit 33 of the ONU 12.
For example, the L2 switch 23 adjusts the data communication amount of the downlink signal addressed to the MAC processing unit 33 so that the QoS parameter (for example, the maximum communication bandwidth (Mbps)) indicated by the management control unit 24 is obtained.

The management control unit 24 instructs the L2 switch 23 to set the QoS parameter value to be set in the MAC processing unit 33. As will be described later, the management control unit 24 instructs the L2 switch 23 on the maximum communication bandwidth for each MAC processing unit 33 notified from the ONU 12. The maximum communication bandwidth of the MAC processing unit 33 may be manually input using the external device 25 connected to the OLT 12 or the ONU 12.
Note that the internal configuration of the OLT 11 is not limited to the configuration of FIG. For example, the PON processing unit 22 and the management control unit 24 may be integrated in one integrated circuit.

The ONU 12 of the present embodiment is an ONU suitable for increasing the communication speed of an existing apartment house (MDU). For this reason, the ONU may be referred to as “MDU-ONU”.
As shown in FIG. 2, the MDU-ONU 12 includes an optical transceiver 31, a concentrator 32, a plurality of MAC processors 33, a plurality of UNI (User Network Interface) ports 34, a coaxial adapter 35, and a management controller. (CPU) 36.

The optical transceiver 31 is an optical device including a circuit for transmitting and receiving an optical signal. The optical transceiver 31 is optically connected to the branch optical fiber 16 (see FIG. 1) and is electrically connected to the concentrator 32.
The optical transceiver 31 mutually converts an optical signal and an electrical signal. That is, the optical transceiver 31 converts a downstream signal composed of an optical signal from the OLT 11 into an electrical signal. The optical transceiver 31 converts an electrical signal from any of the plurality of MAC processing units 33 into an optical signal.

The concentrator 32 is an integrated circuit that determines a communication path between the optical transceiver 31 and the plurality of MAC processors 33. The concentrator 32 includes an aggregator 37 and a distributor 38.
The aggregating unit 37 aggregates a plurality of communication paths respectively connected to the plurality of MAC processing units 33. The distribution unit 38 distributes the downstream signal (electric signal) from the optical transceiver 31 to the plurality of MAC processing units 33.

The concentrator 32 is composed of, for example, an FPGA (Field-Programmable Gate Aarray). But the structure of the aggregation part 37 and the distribution part 38 for achieving the above-mentioned function is not specifically limited.
That is, the aggregation unit 37 may be a logic circuit included in the FPGA, or may be an electric switch. The distribution unit 38 may be a logic circuit included in the FPGA or may be a wiring.

The MAC processing unit 33 performs various processes on the downlink signal and the uplink signal. When the destination MAC address of the downlink signal matches the MAC address of the own device, the MAC processing unit 33 executes processing according to the control frame included in the downlink signal.
For example, the MAC processing unit 33 transmits a data frame included in the downlink signal to the corresponding UNI port 34. In addition to the above processing, the MAC processing unit 33 may execute various processes such as a decoding process and an error correction process.

When receiving a frame from the UNI port 34, the MAC processing unit 33 analyzes the header of the frame. The MAC processing unit 33 temporarily stores the frame.
According to the grant from the OLT 11, one MAC processing unit 33 among the plurality of MAC processing units 33 transmits a frame together with a transmission permission command (burst enable signal).

The UNI port 34 and the coaxial adapter 35 are connected by an Ethernet cable. The UNI port 34 transmits the data frame sent from the MAC processing unit 33 to the coaxial adapter 35.
When the UNI port 34 receives a data frame from the coaxial adapter 35, the UNI port 34 transfers the data frame to the MAC processing unit 33.

The management control unit 36 is connected to one of the plurality of MAC processing units 33. Therefore, the management control unit 36 can communicate with the management control unit 24 of the OLT 11 using the PON line 13.
The internal configuration of the ONU 12 is not limited to the configuration shown in FIG. For example, the management control unit 36, the plurality of MAC processing units 33, and the concentrating unit 32 may be integrated in one integrated circuit.

[Internal configuration of coaxial adapter]
FIG. 3 is a block diagram illustrating an example of the internal configuration of the coaxial adapter 35.
As shown in FIG. 3, the coaxial adapter 35 includes a signal conversion unit 41, a low-pass filter 42, a high-pass filter 43, an Ethernet cable coupler 44, and first and second couplers 45 and 46 for coaxial cable. Is provided.

The signal conversion unit 41 is a converter including an integrated circuit that performs processing for mutually converting an Ethernet signal and an RF signal.
The coupler 44 is connected to the input / output port Pe on the Ethernet side of the signal conversion unit 41. The first coupler 45 is connected to the bidirectional low-pass filter 42. The second coupler 46 is connected to the bidirectional high pass filter 43. The high pass filter 43 is connected to the input / output port Pc on the coaxial cable side of the signal converter 41.

The high-pass filter 43 includes a filter circuit that passes an RF signal of 1 GHz or more and cuts an RF signal lower than 1 GHz, for example.
The low-pass filter 42 includes a filter circuit that passes an RF signal of 1 GHz or less and cuts an RF signal exceeding 1 GHz, for example. The low-pass filter 42 is connected to a branch line that branches from a signal line that connects the high-pass filter 43 and the second coupler 46.

An Ethernet cable 47 leading to the UNI port 34 (see FIG. 2) of the ONU 12 is connected to the coupler 44. The Ethernet signal transmitted from the UNI port 34 is sent to the signal conversion unit 41.
The first coupler 45 is connected to a coaxial cable 48 that transmits an RF signal in the lower first frequency band H1 (1 GHz or less). The RF signal in the first frequency band H1 is transmitted to the second coupler 46 via the low-pass filter 42.

The signal converter 41 converts the Ethernet signal into an RF signal. The converted RF signal is an RF signal in the higher second frequency band H2 (1 GHz or more). The RF signal in the second frequency band H2 is transmitted to the second coupler 46.
Therefore, the RF signal of the first frequency band H1 and the RF signal of the second frequency band H2 are superimposed on the coaxial cable 49 connected to the second coupler 46.

[Application example of ONU to collective housing]
FIG. 4 is a block diagram illustrating an example of a wiring structure of the coaxial communication system 50 laid in the apartment house 100.
As shown in FIG. 4, the apartment house 100 includes one equipment room 101 and a plurality of user homes 102. Although there are two user homes 102 in FIG. 4, there may be three or more homes.

  In FIG. 4, the symbol C is a coaxial cable, and the symbol L is a LAN cable (Ethernet cable). In FIG. 4, a cut portion S indicated by a bidirectional arrow is a portion where the coaxial cable is continuous before the ONU 12 is introduced.

In the following description, the coaxial communication system 50 before the introduction of the ONU 12 is referred to as an “existing system”, and the coaxial communication system 50 after the introduction is referred to as a “new system”.
The existing system includes a 1: N distributor 51 installed in the equipment room 101, a 1: N distributor 52 installed in the user house 102, and a coaxial communication terminal 53 installed in the user house 102. ing.

The distributor 52 in the equipment room 101 is connected to the head end 54 of the communication carrier by a coaxial cable C. The distributor 51 in the equipment room 101 and the distributor 52 in the user house 102 are connected by a coaxial cable C laid on the back of the ceiling or inside the wall.
For this reason, the head end 54 and the coaxial communication terminal 53 of each user home 102 can communicate with each other by an RF signal transmitted to the coaxial cable C. In addition, a resident of the user's home 102 can also watch a TV program by a TV broadcast signal distributed by the head end 54.

In order to introduce the MDU-ONU 12 and change to the new system, for example, the following construction procedure may be executed. First, the construction procedure in the equipment room 101 will be described. 1) The ONU 12 is installed at an appropriate place in the equipment room 101.
2) The coaxial cable C on the branch side of the distributor 51 (opposite side of the head end 54) is divided by the cut portion S.

3) Of the end portions of the divided coaxial cable C, the end portion on the head end 54 side is connected to the first coupler (low band side) 45 of the coaxial adapter 35 of the ONU 12.
4) Of the ends of the divided coaxial cable C, the end on the user home 102 side is connected to the second coupler (high band side) 46 of the coaxial adapter 35 of the ONU 12.
5) The above operations 3) and 4) are performed for the number of user houses 102.

Next, a construction procedure in the user home 102 will be described.
6) Install the coaxial adapter 35 at an appropriate place in the user's home 102.
7) The coaxial cable C on the converging side (head end 54 side) of the distributor 52 is divided by the cut portion S.

8) Of the ends of the split coaxial cable C, the end on the head end 54 side is connected to the second coupler (high band side) 46 of the coaxial adapter 35 of the ONU 12.
9) Of the ends of the divided coaxial cable C, the end on the distributor 52 side is connected to the first coupler (low band side) 45 of the coaxial adapter 35.
10) The gateway 55 is connected to the coupler 44 of the coaxial cable C via the Ethernet cable L.

In the new system obtained by the above construction procedure, the second cable based on the PON signal is added to the coaxial cable C connecting the ONU 12 and the second coupler 46 of the coaxial adapter 35 to the RF signal in the first frequency band H1 of the existing system. The RF signal in the frequency band H2 is appropriately superimposed.
For this reason, in addition to communication services such as television distribution and data communication provided by coaxial communication operators, communication services provided by optical communication operators can be used.

  Further, according to the new system, data communication using the higher second frequency band H2 can be performed. Therefore, since the first frequency band H1 of the existing system is low, Internet communication and the like can be comfortably performed in the housing complex 100 that has a problem such as Internet communication being hindered while watching TV.

  The coaxial communication system 50 in FIG. 4 may be a coaxial communication system newly installed in a newly built apartment house, including not only the case where the ONU 12 is retrofitted to the existing system but also the installation of the coaxial cable C and the like.

[Example of bandwidth limitation by ONU]
By the way, as one of the weak points of the coaxial cable C, there is a point that when a section with poor quality occurs due to deterioration over time, the upper limit of the frequency band is limited and the communication band is also limited. Further, the communication band fluctuates relatively greatly due to the influence of noise.
When the MDU-ONU 12 is used in the housing complex 100 and the RF signal of the second frequency band H2 is superimposed on the coaxial cable C, the RF signal of the desired communication band may be changed depending on the quality of the existing coaxial cable C and the noise environment. There is a possibility that it cannot be superimposed. Therefore, it is preferable to perform bandwidth limitation on the MAC processing unit 33 of the ONU 12.

For example, the signal conversion unit 41 (see FIG. 3) of the coaxial adapter 35 measures the maximum communication band (bps) with the UNI port 34 at the time of link-up, and executes processing for recording the measurement data in the memory. .
Therefore, the coaxial adapter 35 in this case corresponds to an acquisition unit that acquires a maximum communication band that is information used for band limitation of communication using the RF signal of the second frequency band H2.

Referring to FIG. 2, the management control unit 36 of the ONU 12 transmits a bandwidth acquisition request management frame to each coaxial adapter 35 connected to the ONU 12.
The coaxial adapter 35 that has received the management frame returns a management frame of a band acquisition response to the management control unit 36. The coaxial adapter 35 includes the measurement data of the maximum communication band stored in the memory in the management frame to be returned.

Next, the management control unit 36 transmits a control command for setting the notified measurement data of the maximum communication band to the maximum communication band of the MAC processing unit 33 corresponding to the coaxial adapter 35 to the concentrating unit 32.
Thereafter, the line concentrator 32 adjusts the data communication amount of the downlink signal addressed to the MAC processor 33 so that the measurement data of the maximum communication band instructed by the management controller 36 is obtained.

  In this way, according to the measurement data of the coaxial adapter 35, it is possible to limit the band for communication using the RF signal in the second frequency band H2. The maximum communication band notified to the line concentrator 32 may be a set value input from the external device 25 connected to the management controller 36.

However, in the bandwidth limitation by the ONU 12, it is necessary to provide a buffer for bandwidth limitation in each ONU 12 constituting the PON system, so that the equipment cost as a whole system becomes high. Therefore, it is preferable that the OLT 11 that leads the PON communication performs band limitation on the coaxial cable C connected to the subordinate ONU 12.
In this case, it is not necessary to provide a buffer for each ONU 12, and the equipment cost of the PON system can be reduced. Hereinafter, a specific example of bandwidth limitation in this case will be described.

[Example of bandwidth limitation by OLT]
FIG. 5 is a sequence diagram illustrating an example of bandwidth limitation by the OLT 11.
Also here, the signal conversion unit 41 of the coaxial adapter 35 measures the maximum communication band (bps) with the UNI port 34 at the time of link-up, and executes processing for recording the measurement data in a memory.

As shown in FIG. 5, the management control unit 36 of the ONU 12 transmits a management frame for a bandwidth acquisition request to each coaxial adapter 35 connected to the ONU 12 (step ST11).
The coaxial adapter 35 that has received the management frame returns a management frame of a band acquisition response to the management control unit 36 (step ST12). The coaxial adapter 35 includes the measurement data of the maximum communication band stored in the memory in the management frame to be returned.

The management control unit 36 writes the measurement data of the maximum communication band acquired from each coaxial adapter 35 into the database (step ST13).
Next, the management control unit 36 transmits a management frame for bandwidth notification to the management control unit 24 of the OLT 11 (step ST14). The management control unit 36 includes the measurement data of the maximum communication band of each coaxial adapter 35 read from the database in the management frame.

Next, the management control unit 24 transmits, to the L2 switch 23, a control command for setting the measurement data of the maximum communication band notified from the ONU 12 as the maximum communication band of the MAC processing unit 33 corresponding to the coaxial adapter 35 (step S2). ST15).
After that, the L2 switch 23 adjusts the data communication amount of the downlink signal addressed to the MAC processing unit 33 so that the measurement data of the maximum communication band instructed by the management control unit 24 is obtained.

[Another example of bandwidth control by OLT]
FIG. 6 is a sequence diagram illustrating another example of bandwidth control by the OLT 11.
Also here, the signal conversion unit 41 of the coaxial adapter 35 measures the maximum communication band (bps) with the UNI port 34 at the time of link-up, and executes processing for recording the measurement data in a memory.

As shown in FIG. 6, the management control unit 36 of the ONU 12 transmits a management frame for a bandwidth acquisition request to each coaxial adapter 35 connected to the ONU 12 (step ST21).
The coaxial adapter 35 that has received the management frame returns a management frame of a band acquisition response to the management control unit 36 (step ST22). The coaxial adapter 35 includes the measurement data of the maximum communication band stored in the memory in the management frame to be returned.

The management control unit 36 writes the measurement data of the maximum communication band acquired from each coaxial adapter 35 in the database (step ST23).
Next, the management control unit 36 calculates the optimum bandwidth to be applied to all the MAC processing units 33 using the measurement data of the maximum communication bandwidth of each coaxial adapter 35 read from the database (step ST24). For example, when importance is attached to the fairness of the user, the management control unit 36 sets the lowest measurement data as the optimum band to be applied to all the MAC processing units 33.

  Next, the management control unit 36 transmits a result notification management frame to the management control unit 24 of the OLT 11 (step ST25). The management control unit 36 includes the calculated value of the optimum bandwidth calculated in step ST24 in the management frame.

Next, the management control unit 24 transmits, to the L2 switch 23, a control command that sets the calculated value of the optimum bandwidth notified from the ONU 12 as the maximum communication bandwidth of all the MAC processing units 33 (step ST26).
Thereafter, the L2 switch 23 adjusts the data communication amount of the downlink signal addressed to the MAC processing unit 33 so that the calculated value of the maximum communication band instructed by the management control unit 24 is obtained.

[Another example of bandwidth control by OLT]
FIG. 7 is a sequence diagram illustrating another example of bandwidth control by the OLT 11.
Here, it is assumed that setting input is manually performed on the external device 25 (see FIG. 2) connected to the OLT 11.

As shown in FIG. 7, the external device 25 transmits a management frame for a bandwidth setting request to the management control unit 24 of the OLT 11 (step ST31). This management frame includes the setting value of the maximum communication band for all the MAC processing units 33.
The management control unit 24 of the OLT 11 that has received the above management frame transfers the received management frame to the management control unit 36 of the ONU 24 (step ST32).

The management control unit 36 of the ONU 12 that has received the management frame writes the setting value of the maximum communication band included in the received management frame in the database (step ST33).
Next, the management control unit 36 of the ONU 12 transmits a management frame for bandwidth setting response to the management control unit 24 of the OLT 11 (step ST34), and the management control unit 24 sends the received management frame for bandwidth setting response to the external device 25. (Step ST35).

  Next, the management control unit 36 transmits a management frame for bandwidth notification to the management control unit 24 of the OLT 11 (step ST36). The management control unit 36 includes the setting value of the maximum communication band of each coaxial adapter 35 read from the database in the management frame.

Next, the management control unit 24 transmits, to the L2 switch 23, a control command for setting the maximum communication band set value notified from the ONU 12 as the maximum communication band of the MAC processing unit 33 corresponding to the coaxial adapter 35 (Step S21). ST37).
Thereafter, the L2 switch 23 adjusts the data communication amount of the downlink signal addressed to the MAC processing unit 33 so that the setting value of the maximum communication band instructed by the management control unit 24 is obtained.

[Other variations]
The above-described embodiment is to 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.

In the above-described embodiment, the coaxial communication system 50 in FIG. 4 uses a coaxial communication modem (for example, a master unit of the coaxial communication terminal 53 in the user's home 102) that transmits and receives an RF signal in the first frequency band H1 instead of the head end 54. The system configuration may be such that the coaxial communication device) is connected to the main line side of the distributor 51.
In this case, a coaxial communication system in which the base modem and the slave modem 53 of coaxial communication communicate with each other by using the RF signal in the first frequency band H1 using the coaxial cable C as a transmission path.

10 PON system 11 Station side equipment (OLT)
12 Home unit (ONU)
DESCRIPTION OF SYMBOLS 13 PON line 14 Optical splitter 15 Trunk optical fiber 16 Branch line optical fiber 21 Optical transceiver 22 PON processing part 23 L2 switch 24 Management control part (CPU)
25 External Device 31 Optical Transceiver 32 Concentrator 33 MAC Processing Unit 34 UNI Port 35 Coaxial Adapter 36 Management Control Unit (CPU)
37 Aggregation Unit 38 Distribution Unit 41 Signal Conversion Unit 42 Low Pass Filter 43 High Pass Filter 44 Coupler 45 First Coupler 46 Second Coupler 47 Ethernet Cable 48 Coaxial Cable 49 Coaxial Cable 50 Coaxial Communication System 51 Divider 52 Divider 53 Coaxial Communication Terminal 54 Headend (coaxial communication equipment)
55 Gateway 100 Apartment house 101 Equipment room 102 User's house

Claims (8)

A coaxial communication system using a coaxial cable as a transmission path,
A first coaxial cable that is a transmission path of a first RF signal transmitted by the coaxial communication device;
A plurality of second coaxial cables respectively leading to a plurality of user homes;
A distributor for distributing the first RF signal to the plurality of second coaxial cables;
A housing side device for collective housing that communicates with a station side device via a PON line and superimposes a second RF signal converted from a PON signal on the second coaxial cable;
A coaxial communication system comprising: An acquisition unit for acquiring information used for bandwidth limitation of communication by the second RF signal;
2. The coaxial communication system according to claim 1, wherein the home-side apparatus includes a management control unit that performs bandwidth limitation of communication using the second RF signal based on the information notified from the acquisition unit. An acquisition unit for acquiring information used for bandwidth limitation of communication by the second RF signal;
2. The coaxial communication system according to claim 1, wherein the station side device includes a management control unit that performs bandwidth limitation of communication using the second RF signal based on the information notified from the acquisition unit.   4. The coaxial communication system according to claim 2, wherein the bandwidth limitation of communication by the second RF signal is a bandwidth limitation that is fair to the plurality of user homes. 5. The acquisition unit includes an external device that receives an input of the information by an administrator,
The coaxial communication system according to claim 2, wherein the external device notifies the management control unit of the input information. A station side device connected to the PON line;
A plurality of home-side devices connected to the PON line and a coaxial cable of a coaxial communication system and having a function of mutually converting a PON signal and an RF signal;
An information acquisition unit used for bandwidth limitation of communication by the RF signal,
The station-side device is a PON system that executes bandwidth limitation of communication using the RF signal based on the information notified from the acquisition unit. A station side device that communicates with a home side device connected to a coaxial cable of a PON line and a coaxial communication system,
A station-side apparatus that receives information used for band limitation of communication using an RF signal and executes communication band limitation of the RF signal based on the received information. A bandwidth limiting method executed by a station side device communicating with a home side device connected to a coaxial cable of a PON line and a coaxial communication system,
Receiving information used for band limitation of communication by RF signal;
A band limiting method by the station side device, comprising: performing a band limitation of communication by the RF signal based on the received information.

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