JPH09139744A - Broadband optical transmission system - Google Patents

Abstract

(57) An object of the present invention is to provide a broadband optical transmission system capable of providing broadband VOD, CATV and bidirectional data services in addition to narrowband telephone and data transmission services. And SOLUTION: A first wideband signal by ATM cells (cells) multiplexed by a means 13 is treated as an STS-3c signal (3c signal) by a means 21 and transmitted to a first OC12 optical transmission line, and means 14, 16 are provided. After switching the second wideband signal by the cell from the means 20 to the route according to the routing information, the means 22 treats it as the 3c signal and the second OC
12 transmitting to 12 optical transmission lines, each transmitting 3c signal cell means 2
5, multiple cells are copied, and the ATM cell-formatted voice signal by means 24 is multiplexed to means 3c signal by means 26-27 and optically transmitted to means 28-29, and means 28-29 multiplex wideband signal and voice. The signal is separated, the separated wideband signal is converted into an analog signal, and the analog signal is transmitted to the subscriber terminal 32.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a broadband optical transmission system. In a digital loop carrier system installed by BOC (Bell Operating Company) in North America, a system capable of supporting a VOD (Video on Demand) service and a two-way data service has recently been required.

As an alternative to CATV (Cable Television), there is a demand for a system capable of providing high-definition images to each subscriber by more reliable digital transmission.

Against this background, AT is a means for collectively transmitting services having different frequency bands.
A broadband optical transmission system using a demultiplexing method based on M (Asynchronous Transfer Mode) enables telephones, data, DS1 / DS3 / ST for North America.
In addition to S1 / OC3 transport services, VO
Broadband services such as D, CATV, and ATM data transmission are provided to subscribers.

However, DS1 and DS3 are digital signals.
-level1, 3 is an abbreviation, and is a signal specified by North American standard TR-008. The DS0 that appears later in the text is 64K
b / s, DS1 is 1.544Mb / s, DS3 is 44M
The band of b / s is shown.

STS1 is the Synchronous Transport
Abbreviation for Signal-level 1 concatenation, SO in North America
NET (Synchronous Optical Network)
It is one of the formats specified in. STS-
1 is 51.84 Mb / s, STS-3c is 150 Mb / s
The band of s is shown.

OC3 is an abbreviation for Optical Carrier level-3 and is defined by North American SONET standard GR-253. OC3 is 155.52 Mb / s, OC12 is 62
The band of 2.08 Mb / s and OC48 shows 2 Gb / s.

In addition, DS1 / DS3 / STS1 / OC3
Transport services are DS1 / DS3 / STS
1 / OC3 transport service, DS1 / DS3 / S
This shows that the input / output interface of TS1 / OC3 is provided.

[0008]

2. Description of the Related Art As a conventional optical transmission system, there is an active star type narrow band FITL (Fiber In The Loop) system for providing services to subscribers by an optical fiber.

This system is based on NFS1 (Narrowband Fi
ber Service Shelf) is a CM that has functions such as SONET demultiplexing for telephone services and DS0 cross connect.
It provides a service performed by connecting to S (Common shelf), and provides a DS0 level signal by FITL.

This is not to provide the service by the optical fiber to each subscriber, but to use a single optical fiber for a plurality of subscribers, and to use a copper wire from an O / E (optical / electrical) conversion device installed outdoors. To provide services.

[0011] STBs located in each subscriber's house
A system in which the image service is provided in the (Set Top Box) section is shown in FIG. 10 and will be described. In FIG. 10, reference numeral 130 is a BHE (Broadcast Head End) unit, 131 is an HDT (Host Digital Terminal) station configured by including a receiving unit (Rx unit) 132 and a transmitting unit (Tx unit) 133,
134 is a BAS (Broadband Access Shelf) section, 135-
Reference numeral 136 is a large number of STB units.

The dozens of channels of the analog image are sent to the BHE section 130 using an optical analog device, and the BH
64QAM after converting to analog image in E unit 130
Frequency multiplexing is performed using the (Quadrature Amplitude Modulation) method. AM of 550MHz obtained by this
The signal is transmitted to the HDT station 131 via the optical fiber.

Then, after being received by the Rx unit 132 of the HDT station 131, it is transmitted from the Tx unit 133 to the BAS unit 134 via the working optical fiber or the standby optical fiber. Furthermore,
One coaxial cable from the BAS unit 134, for example 500
Transfer to the subscriber's STB units 135 and 136 by connecting to the bus. This allows the STB units 135 and 136 to receive an image service for selecting a desired program.

[0014]

The narrow band FITL system, which is the above-mentioned conventional optical transmission system, has the following problems.
It has an exchange interface of OC3 and OC12, but S
Processing data at TS-1 level, STS-3c
Since signal processing at the level is not possible and the interface with the subscriber terminal is DS0 and DS1, the serviceable bandwidth is limited. In addition to narrowband telephone and data transmission services, wideband VOD and CATV are also available. Also, there is a problem that the interactive data service cannot be provided.

In the image service system as shown in FIG. 10, the optical analog device, 64QAM
Introduced equipment such as equipment is large and expensive, and since one coaxial cable branching to the subscriber is connected to the bus, if it is shorted or opened, waveform reflection occurs and there is a problem that it interferes with other subscribers. there were.

Further, since it is analog image transmission, it is possible to easily eavesdrop, which has a problem that it can be eavesdropped even if scramble prevention is performed, and further there is a problem that bidirectional transmission cannot be easily realized.

The present invention has been made in view of the above circumstances, and is capable of providing broadband VOD, CATV, and bidirectional data services in addition to narrowband telephone and data transmission services. It is intended to provide a transmission system.

[0018]

FIG. 1 shows the principle of a broadband optical transmission system according to the present invention. The wideband optical transmission system shown in this figure uses a multiplexing and demultiplexing method based on ATM which is an asynchronous transfer mode.

In the figure, 13 is a multiplexing means, which multiplexes the first wideband signal by the ATM cell and optically transmits. 14 and 16 are communication service supply means, and ATM
The second optical broadband signal is transmitted by the cell.

Reference numeral 20 is an ATM switch means, which optically transmits the second wideband signal to a route according to the routing information of the ATM cells from the communication service supplying means 14 and 16. Reference numeral 21 is a first demultiplexing means, and the demultiplexing means 1
1st wideband signal from 3 is ST of the North American synchronous optical communication network standard
It is treated as an S-3c signal, multiplexed, and transmitted to the first OC12 optical transmission line of the North American synchronous optical communication network standard.

A second demultiplexing means 22 treats the second wideband signal from the ATM switching means 20 as an STS-3c signal of North American synchronous optical communication network standard, multiplexes it, and transmits it to the second OC12 optical transmission line. It is a thing.

A BFS means 25 is an AT for the STS-3c signal transmitted through the first and second OC12 optical transmission lines.
This is to copy M cells into a plurality. Reference numeral 24 is a CMS means for processing a voice signal by a demultiplexing method in a synchronous transfer mode. Reference numerals 26 to 27 denote BTS means for converting the voice signal from the CMS means 24 into an ATM format, and an AT obtained by this ATM formatting.
STS the M cell and the ATM cell from the BFS means 25.
-3c signal is multiplexed and transmitted by distributed light.

28-29 are BAS means, which are the first signals multiplexed on the STS-3c signals from the BTS means 26-27.
And the second wideband signal and the voice signal are separated, the separated first and second wideband signals are converted into analog signals, and then the paths corresponding to the routing information of the ATM cells of the first and second wideband signals are set. The data is transmitted to a large number of subscriber terminals 32 via the Internet.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of a broadband optical transmission system according to an exemplary embodiment of the present invention.

The wideband optical transmission system of this embodiment is
By using the multiplex / separation method based on TM, communication services having different bands are collectively transmitted.

In FIG. 2, reference numerals 11 and 12 denote RTE (R
The eal Time Encoder) part 13 is an ATM multiplexing part. 1
Numerals 4 and 16 are VS (Video Server) units, each having a code 1
It has an L2GW (Gateway) part shown by 5,17. 18 is the L1GW section.

Reference numeral 19 denotes a central station, which is an AT indicated by reference numeral 20.
M-SW (Switch) section, S for BC (Broadcast) indicated by 21
It has an ONET demultiplexing unit and a VOD SONET demultiplexing unit 22.

Reference numeral 23 is an HDT station, and CMS indicated by 24.
Part, BFS (Broadband Feeder Shelf) part indicated by 25, 2
First to tenth BTSs (Broadband Tributa 6 to 27)
ry Shelf) section. 28 to 29 are 1st to 12th BA
It is part S.

Reference numeral 30 designates a house, which is a telephone indicated by 31 and 3
It has an STB section shown by 2 and a TV shown by 35. Where S
The TB unit 32 uses a NIM (Network Interfa
ce Module) part, CAM (Consumer Appliance) 34
Module) part.

The line connection of such components will be described. VS section 14, 16 and L1GW section 18 and ATM-S
The W section 20 is connected by an OC3 optical fiber. AT
The M multiplexing unit 13 and the SONET demultiplexing unit for BC 21 are OC
The ATM-SW unit 20 is connected by 3 × 4 optical fibers.
The VOD SONET demultiplexing unit 22 is connected by an OC3 × 4 optical fiber, and the demultiplexing unit 21 and the BFS unit 2 are connected.
5. The demultiplexing unit 22 and the BFS unit 25 are connected by an OC12 optical fiber. In other words, one HDT station 23 has a SONET demultiplexing unit 21 for BC and VOD.
22 are connected by OC12 optical fibers.

The BFS unit 25 includes ten BTS units 26-2.
7 is connected by an optical fiber. In this connection, as shown by reference numerals 38, 39, and 40 in FIG. 3, the BFS unit 25 and the respective BTS units 26, 26a, and 27 have a 2.4 G clockwise rotation.
It is ring-connected with a main optical fiber which is a lower direction line of b / s, and as shown by reference numerals 41, 42 and 43, it is ringed with a standby optical fiber which is a lower direction line of 2.4 Gb / s counterclockwise. The BTS units 26, 26a, 27 and the BFS unit 25 are connected to each other by reference numerals 44, 4 respectively.
As shown by reference numerals 5 and 46, they are connected by an optical fiber of OC3, which is an upper direction line.

GP # 1 shown in FIG. 3 is a group number of four STS-3c SONET format signals for transmitting the optical fiber of OC12 that connects the BFS unit 25 and the demultiplexing units 21 and 22 (FIG. 2). Is shown.

CM having audio signal processing function shown in FIG.
A telephone voice signal is inputted to the S section 24 through the optical fiber of OC3, and the CMS section 24 and each of the BTS sections 26 to 27 are optical fibers for transmitting the STS-1 signal. It is connected.

Further, the first BTS unit 26 and 12 BAS units
The parts 28 to 29 are connected by an OC3 optical fiber. Although not shown, each of the other nine BTS units is similarly connected to the twelve BAS units by the OC3 optical fiber.

The above connection is made by an optical fiber, and the other connection is made by a coaxial cable or the like. That is, the first BA
The ST section 32 to which the S section 28, the telephone 31 of the house 30 and the TV 35 are connected is connected by a coaxial cable. However, one BAS unit is connected to telephones and STB units of 16 houses. RTE section 11, 12
The ATM multiplexer 13 and the L1GW 18 and the ATM multiplexer 13 are also connected by a coaxial cable.

The L2GW section 17 and the L1GW section 18 use a CDN (Data Connec) that uses a LAN or the like as a communication path medium.
communication network). FIG. 2 described above
All signals transmitted to the connection line in the broadband optical transmission system shown in (1) are based on ATM cells.

Next, the function of each component will be described. RT
The E sections 11 and 12 convert the analog video signal received by the broadcasting station indicated by reference numeral 138 in FIG. 2 into a digital signal in real time. ATM multiplexing unit 13
The digital video signals output from the TE units 11 and 12 are digitized, converted into ATM cells, further multiplexed, and output to the demultiplexing unit 21.

The L2GW units 15 and 17 perform control for receiving program selection information from the STB unit 32 in the VOD service and extracting programs, and transmitting the video signals of the extracted programs from the VS units 14 and 16. Is.

The L1GW section 18 carries out the following controls (1) to (3). VP (Virtual Path) / VC (Vir
tual Channel: Virtual channel) It has a setting control program, and when the STB unit 32 starts up, the STB unit 32
VPI (Virtual Path Identifier)
Boot processing such as determining the value of / VCI (Virtual Channel Identifier) is performed.

ST in Broadcast Service
The HDT station 23 is instructed to set a path in response to a program selection instruction from the B section 32. This instruction is given through a path that passes through the ATM multiplexing unit 13. It also controls the ATM multiplexer 13.

In response to a server request from the STB unit 32 in the VOD service, H is sent via the ATM-SW unit 20.
The path setting to the DT station 23 is instructed, and the video control channel between the L2GW units 15 and 17 and the STB unit 32 is designated. The operation state of the STB unit 32 is confirmed.

The ATM-SW unit 20 automatically selects a route from the input port to the output port (routing).
This is A, which is input from the VS units 14 and 16.
VPI / routing information in the header of the TM cell
It is performed by reading the VCI.

The SONET demultiplexing unit for BC 21 uses the AT
The signal of 150 Mb / s × 4 from the M multiplexing unit 13 is 600
It is converted into Mb / s and transmitted to the BFS unit 25. Maximum 7 on the OC12 line for BC where the transmission is performed
Two-channel (6M / ch) video information is supplied from the server connected to the RTE units 11 and 12 via the ATM multiplexing unit 13. Also, OC1 for BC
An ATM multiplexing unit 1 is provided between the two lines and the RTE units 11 and 12.
VP / VC is fixedly set at 3.

The SONET demultiplexing unit 22 for VOD is
6 signals of 150 Mb / s × 4 from the TM-SW unit 20
It is converted to 00 Mb / s and transmitted to the BFS unit 25. Video information of up to 112 channels (4M / ch) is transmitted to the OC12 line for VOD for which the AT is transmitted.
It is supplied from the VS units 14 and 16 via the M-SW unit 20. OC12 line for VOD and VS unit 1
ATM between 4 and 16 is instructed by the L1GW unit 18.
The VP / VC is set by the SW unit 20.

The OC12 × 2 optical fibers between the demultiplexing unit 21 and the BFS unit 25 and between the demultiplexing unit 22 and the BFS unit 25 can be replaced with one OC48 optical fiber. In this case, the transmission capacity can be improved and the facility can be simplified.

The HDT station 23 receives the video information from the demultiplexing units 21 and 22 at a maximum of 12 units × 10 BAS units 28 to 2.
9 and the control signal from the STB unit 32 is relayed, and the STM (Synchronous Transfe
r Mode: Synchronous transfer mode) It controls to convert the audio signal of the format to the ATM format in order to match it with the video signal.

Also, the OC12 line connecting the demultiplexing units 21 and 22 and the HDT station 23, the HDT station 23 and the BA.
VP / V with the OC3 line connecting the S sections 28 to 29
C is set according to an instruction from the L1GW unit 18.

The BAS units 28-29 distribute the video information from the HDT station 23 to the STB unit 32 by 16 pair lines and relay the control signal from the STB unit 32.

However, the distribution by the pair line is performed to the STB section 32 of a maximum of 1920 units. Also, H
VP from OC3 between DT station 23 and BAS units 28-29
/ VC is fixedly allocated to 16 STB units 32.

The STB section 32 has a function of terminating an ATM cell and compressing video information from the ATM cell.
In addition, the channel selection signal generated by the subscriber selecting the channel is relayed, and the L1GW unit 18 and the L2G unit are connected.
It communicates with the W units 15 and 17.

Next, the configuration of the BFS unit 25 of the HDT station 23 will be described with reference to FIG. The BFS unit 25 duplicates the STS-3c signals from the demultiplexers 21 and 22 1:10 in the lower direction, and duplicates the 10 STS-3c signals.
The signal is transmitted to the first to tenth BTS units 28 to 29, and the first to tenth BTS units 28 to 29 are arranged in the upper direction.
The STS-3c signal from is mapped to a desired path and transmitted.

In the BFS unit 25 shown in FIG. 4, 49 is a SONET termination unit, which has functions such as SONET demultiplexing, path switch, and network communication channel termination.

50 is an STS-3c / TSW (Time Slot S
witch) part, and STS- from the SONET terminal part 49
The 3c × 8 signal is output after switching to a time slot, for example, from 2 to 8, 3 to 1, and so on. However, the SONET termination unit 49 is OC
When 48 optical fibers are connected, an STS-3c × 16 signal is output.

Reference numeral 51 is a MUX (Multiplexer) unit,
STS-3c x 8 (or STS-3c from the SW unit 50
X16) signals are multiplexed and output.
Reference numeral 52 denotes an E / O (electrical / optical) converter, which is a MUX unit 51.
BTS units 28 to 29 by converting electric signals from the optical signals into optical signals.
To send to.

However, the E / O converter 52 and the BTS unit 28-
The number of optical fibers connecting 29 is OC12 × 2 during signal transmission of STS-3c × 8, and STS-3c × 1.
At the time of 6 signal transmission, it becomes OC12 × 4.

53 is an O / E (optical / electrical) converter,
BTS unit 28-2 through OC3 × 10 optical fibers
The optical signal transmitted from 9 is converted into an electrical signal and output.

Reference numeral 54 is a DMAP (De-Mapping) unit,
The STS-3c signal from the / E conversion unit 53 is distributed to ATM cells to synchronize them. 55 is ATM
The SW cell, which is an ATM cell from the DMAP section 54,
The data is transmitted to the route according to the routing information via the SONET terminating unit 49.

Next, the BTS units 26 to 27 of the HDT station 23
The configuration will be described with reference to FIGS. 5 and 6. However, FIG.
Is a block diagram of the lower direction signal processing circuit of the BTS units 26 to 27, and FIG. 6 is a block diagram of the higher direction signal processing circuit.

In FIG. 5, reference numeral 58 is an O / E converter, which converts the optical signal from the BFS unit 25 into an electric signal. 59 is a 1: 2 COPY (copy) section,
The electric signal from the O / E conversion unit 58 is copied into two, and one is output to the E / O conversion unit 60 and the other is output to the DMAP unit 61.

Reference numeral 60 is an E / O converter, which is 1: 2 COP.
The electric signal from the Y section 59 is converted into an optical signal and output to the BTS section of the next stage ring-connected based on the BFS section 25 as described with reference to FIG.

Reference numeral 61 is a DMAP section, which is 1: 2COPY
The STS-3c signal, which is an electric signal from the unit 59,
It distributes them to cells and synchronizes them. Reference numeral 62 denotes an OAM (Operation Administration and Maintenance) cell separation unit, which extracts from the DMAP unit 61 OAM cells which are maintenance information of the ATM layer of the lower direction circuit of the BTS unit to a control unit which processes an OAM cell not shown. It is what is sent.

63 is routing control / VPI / VCI
The conversion unit controls which route the ATM cells separated by the DMAP unit 61 pass through, and also controls the replacement of the VPI / VCI which is the destination address of the ATM cells.

Reference numeral 64 denotes an ATM-SW unit which transfers the ATM cells from the DMAP unit 64 to the first to twelfth BAS units 28 to 28.
The number corresponding to the number of 29 (FIG. 2) is copied and transmitted to the route according to the routing information.

As shown in FIG. 8, the ATM-SW unit 64 receives A's from the individual input ports 140 to 143.
Each TM cell is a buffer (Buf) which is a FIFO memory.
fer) 144-147 to a plurality of output ports. That is, copying is performed in ATM cell units between STS-3c.

Reference numerals 64a and 64b denote cell multicast units, which are functions included in the output port of the ATM-SW unit 64, and both have the configuration shown in FIG.
In FIG. 9, 153 is a FIFO memory unit, 154 is a cell payload memory unit, 155 is a header replacement unit, 156.
Is a copy control unit.

The FIFO memory unit 153 is an ATM-SW.
The ATM cells sent from the unit 64 are accumulated until the copying in the subsequent stage is completed, and the ATM cells accumulated when the copying is completed are transmitted to the subsequent stage. This control is performed by the copy controller 156.

The cell payload memory section 154 stores the payload section of the ATM cell sent from the FIFO memory section 153 under the control of the copy control section 156. The header replacement unit 155 has a copy control unit 156.
The VPI / STP section which differs from STB section to the payload section read from the cell payload memory section 154 under the control of
The VCI header is rewritten, added, and sent to the subsequent stage. The operation of reading the payload section from the cell payload memory section 154 and adding the header is repeated for the number of copies.

When this copying is completed, the copy controller 156
Is controlled so as to send the next ATM cell from the FIFO memory unit 153. 65-66 is the first
The number of VP / VC converters corresponding to the number of twelfth BAS units 28 to 29 (FIG. 2) is provided, and the VPI / VCI of the ATM cells copied by the ATM-SW unit 64 is replaced. .

Reference numeral 67 is an L1GW / L2GW signaling interface section, which terminates the ATM adaptation layer to control a software of the ATM adaptation layer by software and perform a protocol processing of an upper layer to a CPU (not shown). It is what is output.

The ATM adaptation layer is a cell division / assembly sublayer (S
AR: Segmentation And Reassembly sublayer) and a Convergence Sublayer (CS), which is a function for each user data unit.

Reference numeral 68 denotes a CMS interface section, which is C
The STS-1 voice signal from the MS unit 24 is captured and transmitted to the subsequent stage. A format conversion unit 69 converts the STS-1 voice signal from the interface unit 68 into an ATM cell.

70 and 73 are VF (Voice Frequency) M
IX (Mixer) section, 71 and 74 are MUX sections, 72 and 75 are E / O conversion sections, and VF / MIX section 70 (or 7
3), MUX unit 71 (or 74), E / O conversion unit 72
The connection sequence of (or 75) is the first to twelfth BAS units 28-
It is assumed that there are as many as 29 (FIG. 2), and the same processing is performed for each series, so only the elements of the series connected to the first BAS unit 28 will be described here.

The VF / MIX section 70 mixes the audio signal ATM cells from the format converting section 69 with the video signal ATM cells from the VP / VC converting section 65. The MUX unit 71 multiplexes the signal from the VF / MIX unit 70. The E / O conversion unit 72 converts the electric signal from the MUX unit 71 into an optical signal to convert the electric signal to the first BAS unit 2.
8 is output.

In FIG. 6, 78 and 81 are O / E converters, 79 and 82 are DMUX (De-Multiplexer) units, 80 and
Reference numeral 83 is a VF / DMIX (De-Mixer) unit. The O / E converter 78 converts the optical signal from the first BAS unit 28 into an electric signal. The DMUX unit 79 separates the signal from the O / E conversion unit 78. VF / DMIX
The unit 80 separates a voice signal ATM cell and a video signal ATM cell.

Reference numeral 84 is a format conversion unit for VF /
Voice signal ATM cells from the DMIX units 80 and 83 are set to ST
The signal is converted into an S-1 signal. Reference numeral 85 denotes a CMS interface section, which is an S from the format conversion section 84.
The audio signal of TS-1 is transmitted to the CMS unit 24.

Reference numerals 86 to 87 are VP / VC converters,
The VPI / VCI of the video signal ATM cells from the F / DMIX units 80 and 83 is changed, and 88 is an L1GW / L2GW signaling interface unit. An OAM cell insertion unit 89 controls the OAM cell from the control unit so that the ATM-SW unit 90 inserts it into the ATM cell.

Reference numeral 90 is an ATM-SW section. 91 is ST
It is an S-3c frame creation unit. Reference numeral 92 denotes an E / O conversion unit, which converts an electric signal from the STS-3c frame creation unit 91 into an optical signal and outputs the optical signal to the BFS unit 25.

Next, the configuration of the BAS units 28 to 29 will be described with reference to FIG. In FIG. 7, 94 is an O / E conversion unit, 95 is a DMAP unit, and 96 to 97 are 16 units of 16QA.
These are M modulators, which are components of the lower direction circuit, and 16QAM modulators 96 to 97 are connected to the STB unit 32 via a coupler (transformer) denoted by reference numeral 98. In this connection, one coupler 98 is connected to one 16QAM modulator.

99 to 100 are 16 QPSK (Quadri
Phase Shift Keying) Demodulator, 101 is a MAP (Mappin)
g) part, 102 is an E / O conversion part, and these are components of the upper direction circuit, and QPSK demodulation parts 99-100
Are connected to the STB section 32 via a coupler 98.
In this connection, one combiner 98 is connected to one QPSK demodulation unit 99.

The optical signal from the BTS unit 26 is converted into an electric signal by the O / E conversion unit 94, then separated into ATM cells by the DMAP unit and synchronized, and the 16-QAM modulation unit 96 performs 16-value amplitude phase modulation. After that, the data is transmitted to the STB unit 32 via the coupler 98.

The signal from the STB section 32 is transmitted to the QPSK demodulation section 99 via the combiner 98, where it is subjected to four-phase phase modulation, and then the MAP section 101 inserts the AT into the STS-3c.
Mapping for arranging M cells is performed, and E / O conversion unit 1
At 02, it is converted into an optical signal and transmitted to the BTS unit 26.

In the broadband optical transmission system having the above-mentioned structure, services from different media are put in a data block called ATM cell and STS-3c S
It is treated as an ONET format signal.

The operation in the subscriber direction (lower direction) is as follows.
Data is copied 1:10 in the BFS unit 25 of the HDT station 23, and the ATM cell is interfaced from the copied STS-3c to the STB unit 32, which is a specific service integration device, according to the determined routing information. ~
It is passed to the 10th BTS units 26 to 27.

The voice signals processed by the first to tenth BTS units 26 to 27 using the demultiplexing method in the synchronous transfer mode are converted from STS-1 to ATM cells and are formatted by the VOD ATM cells. The data is multiplexed with the STS-3c signal, converted into an optical signal, and then transferred to the first to twelfth BAS units 28 to 29 which are specific subscriber distribution devices.

The routing information at this time is the L1GW unit 1
8 to the BTS units 26-27, where the VPI / VCI of the ATM cell is contrasted with the device connection route.

In the first to twelfth BAS units 28 to 29, S
The ATM data and the STM voice signal are separated from the TS-3c signal, and the ATM data is a specific subscriber terminal by comparing the VPI / VCI with the device connection route.
It is transferred to the TB unit 32.

At this time, in the BAS units 28 to 29, the existing C
In order that the ATV signal can be provided on the STB section 32 on the same transmission medium, the digital ATM data is 16Q.
It is transferred to the STB unit 32 as an analog signal by being subjected to AM digital modulation. In the STB section 32, after the analog signal is demodulated into digital ATM data,
Converted to a media signal.

In the operation toward the switching network (upper direction), the STB unit 32 sends the media signal to the ATM.
After being converted into data and converted into an analog signal by QPSK digital modulation, it is transferred to the BAS units 28 to 29.

The analog signals are demodulated into digital ATM data by the BAS units 28 to 29, and the exchange transfer STM is performed.
The ATM format signal of the voice signal and the STS-3c signal are multiplexed, and the multiplexed signal is converted into an optical signal and transferred to the BTS units 26 to 27.

The BTS units 26 to 27 separate ATM data and STM voice signals from the STS-3c, and
The data is sent to the BFS unit 25, and the BFS unit 25
Data for 10 units of the BTS units 26 to 27 is multiplexed, and S
After being converted into a TS-3c signal and converted into an optical signal, VS is transmitted through a switching network including the central office 19.
It is transferred to the units 14 and 16.

In the broadband optical transmission system described above, in addition to the CMS unit 24, the BFS unit 25 for the multimedia network has OC12 × 2 systems or OC48 ×.
Since it has a function of terminating one system, it is possible to provide a communication service in a band of DS1 or higher. Also,
ST from the CMS unit 24 by the BTS units 26 to 27
Converts M signal to ATM format, and also BFS unit 2
Since the ATM data from 5 can be converted into the STS-3c signal, the DS0 and DS1 services can be combined / separated.

That is, the BFS unit 25 has the OC12 or OC
Interface with ATM network at 48, but S
Since ATM cells are mapped to TS-3c,
This is divided into ATM cells by the BTS units 26 to 27. Further, since the signal handled by the CMS unit 24 is an STM signal, this is converted into an ATM format by the BTS units 26 to 27, and the STS-3c is formed together with the ATM cells previously separated.
I put it on. As a result, it is possible to extend the system to support wideband services without changing the conventional narrowband service device.

Since the optical transmission lines of OC3 and OC12 are provided in the interface between the BFS unit 25 and the BTS units 26 to 27, it is possible to provide the narrow band service, the conventional telephone service and the DS1 service up to 64 subscribers.

Since the BTS units 26 to 27 have a 12 × 1 routing function and a copying function in the upper direction and a 9 × 14 routing function in the lower direction, multimedia services can be provided between the network and subscriber terminals. It can be processed in both directions.

In addition, the BAS units 28 to 29 and a large number of STBs
By performing the communication between the parts 32 using the ATM cell, that is, by providing the communication service from the digital image broadcasting station to a wide range of subscribers using the ATM cell, it is possible to distribute a high-quality image with little deterioration and it is difficult to eavesdrop. In addition, bidirectional transmission is easy, and services such as bidirectional delevi are possible.

[0096]

As described above, according to the broadband optical transmission system of the present invention, it is possible to provide VOD, CATV and two-way data services in addition to telephone and data transmission services.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of a broadband optical transmission system according to an exemplary embodiment of the present invention.

FIG. 3 is a connection diagram between a BFS unit and a BTS unit of the HDT station shown in FIG.

FIG. 4 is a block diagram of a BFS unit shown in FIG.

5 is a block configuration diagram of a lower direction signal processing circuit of the BTS unit shown in FIG.

FIG. 6 is a block configuration diagram of an upper direction signal processing circuit of the BTS unit shown in FIG.

FIG. 7 is a block configuration diagram of a BAS unit shown in FIG.

8 is a schematic configuration diagram of an ATM-SW unit shown in FIG.

9 is a block diagram of a cell multicast unit shown in FIG.

FIG. 10 is a diagram of a conventional image service system.

[Explanation of symbols]

 13 Multiplexing means 14, 16 Communication service supplying means 20 ATM switching means 21 First demultiplexing means 22 Second demultiplexing means 24 CMS means 25 BFS means 26-27 BTS means 28-29 BAS means 32 Subscriber terminal

Claims (11)

[Claims] 1. A wideband optical transmission system using a multiplexing and demultiplexing system using ATM which is an asynchronous transfer mode. Multiplexing means for multiplexing and transmitting a first wideband signal by ATM cells and second wideband signals by ATM cells. And an A for optically transmitting the second wideband signal to a path according to the ATM cell routing information from the communication service supplying means.
The TM switch means and the first wideband signal from the multiplexing means are treated as an STS-3c signal of the North American synchronous optical communication network standard, multiplexed, and transmitted to the first OC12 optical transmission line of the North American synchronous optical communication network standard. The demultiplexing means and the second wideband signal from the ATM switch means are sent to the STS.
-3c signal, which is multiplexed and transmitted to the second OC12 optical transmission line, and the ST which has passed through the first and second OC12 optical transmission lines.
BFS means for copying the ATM cells of the S-3c signal into a plurality, CMS means for processing the voice signal by the multiplexing and demultiplexing method by the synchronous transfer mode, and the voice signal from the CMS means is ATM-formatted, and this ATM-formatted The ATM cell obtained by STS-3c and the ATM cell from the BFS means.
BTS means for multiplexing and transmitting distributed light in a signal format, and a first STS-3c signal multiplexed from the BTS means.
After separating the first and second wideband signals and the voice signal from each other and converting the separated first and second wideband signals into analog signals, a route corresponding to the routing information of the ATM cells of the first and second wideband signals is provided. A broadband optical transmission system comprising: BAS means for transmitting to a large number of subscriber terminals via the same. 2. The BAS means demodulates an analog wide band signal from the subscriber terminal into a digital wide band signal which is an ATM cell, and the demodulated wide band signal and a voice signal which is the ATM cell are the STS. -3c signal is multiplexed and optically transmitted to the BTS means, the BTS means separates the wideband signal and the voice signal from the STS-3c signal from the BAS means, and the separated wideband signal is While transmitting to the BFS means, the separated voice signal is formatted into the synchronous transfer mode and transmitted to the CMS means, the BFS means multiplexes the wide band signals from the plurality of BTS means, and then STS-3c. 2. The broadband optical transmission system according to claim 1, wherein the signal is formatted into a signal and is optically transmitted to the first and second demultiplexing means. 3. The first and second demultiplexing means and the B
3. The wideband according to claim 1, wherein one OC48 optical transmission line of North American synchronous optical communication network standard is used in place of the first and second OC12 optical transmission lines connecting with FS means. Optical transmission system. 4. The BFS means and a plurality of the BTS means are arranged in a lower direction from the communication service supplying means to the subscriber terminal, and each BTS means is provided to the BFS means.
The means is a subordinately connected ring connection, and is a one-to-one connection in which each BTS means is individually connected to the BFS means in the upper direction from the communication service supply means to the subscriber terminal. The broadband optical transmission system according to claim 1 or 2. 5. The BT for one BFS means
3. The broadband optical transmission system according to claim 1, wherein n S units are connected, and m BAS units are connected to the one BTS unit. 6. The AT in the lower direction is provided by the BTS means.
OAM for extracting the OAM cell that is the maintenance information of the M layer
The broadband optical transmission system according to claim 1 or 2, further comprising a cell separating unit. 7. The BTS means is a × in the lower direction.
The broadband optical transmission system according to claim 1 or 2, further comprising an ATM cell routing means (b). 8. The BTS means includes x in the lower direction:
3. The broadband optical transmission system according to claim 1, further comprising an ATM switch means for copying an ATM cell to y and assigning an address to the subscriber terminal. 9. The BTS means is c × in the upper direction.
3. The broadband optical transmission system according to claim 1, further comprising an ATM switch means for switching an ATM cell to d. 10. The wideband optical transmission system according to claim 1, wherein the multiplexing means multiplexes the second wideband signal from the communication service providing means with the first wideband signal. 11. A port of the ATM switch means,
First storage means for accumulating the ATM cells sent from the preceding stage in the order of input, second storage means for storing the payload part of the ATM cells sent from the first storage means, and read from the second storage means A replacement means for rewriting and adding a different address for each subscriber terminal to the payload section and a different address for each subscriber terminal for rewriting and adding to the header section of the ATM cell read from the second storage means. And a copy control means for controlling the operation to repeat the required number of copies and sending the ATM cells accumulated in the first storage means to the second storage means after the control for repeating the required number of copies is completed. The wideband optical transmission system according to claim 8, wherein