JP3123633B2 - 1: n communication transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission system of 1: n communication capable of performing multiplex communication with one station side transmission device and a large number of subscriber side transmission devices with high reliability.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram showing an example of a conventional configuration in 1: n communication. In this figure, for convenience of explanation, multiplexing is performed in one station side transmission apparatus and two subscriber side transmission apparatuses. The case where communication is performed is shown.

[0003] As shown in FIG.
And the subscriber-side transmission devices 300 and 400 as the destinations.
Means that the optical fibers 200, 201 and 202 and the optical fibers 220, 221 and 222 are transmitted as transmission media. Optical couplers 210 and 230 for branching to the subscriber-side transmission devices 300 and 400 and coupling to the station-side transmission device 100 are provided in the middle of the paths of the respective transmission media.

The station-side transmission device 100 includes two transmission / reception units 110 and 120 for transmitting and receiving signals to and from the opposing subscriber-side transmission devices 300 and 400, a changeover switch 130 for switching a transmission signal between these systems, And a changeover switch 140 for selecting a reception signal from these systems.
On the other hand, the subscriber-side transmission device 300 includes two transmission / reception units 31 for transmitting and receiving to and from the opposite station-side transmission device 100.
0, 320, a changeover switch 330 for switching a transmission signal to these systems, and a changeover switch 340 for selecting a reception signal from these systems. Similarly, the subscriber-side transmission device 400 includes two transmission / reception units 410 and 420 for transmitting and receiving to and from the opposite station-side transmission device 100,
Switch 43 for switching the transmission signal to these systems
0 and a changeover switch 440 for selecting a received signal from these systems.

[0005] In the station side transmission device 100, the transmitting and receiving unit 1
10 is connected to the transmitting / receiving unit 310 of the subscriber-side transmission device 300 and the transmitting / receiving unit 410 of the subscriber-side transmission device 400 via the optical fibers 200, 201, and 202. In the optical fiber 200, the subscriber-side transmission devices 300 and 4
At the branch point to 00, an optical coupler 210 is installed to branch and combine the transmission signal. Similarly, the transmission / reception unit 120 is connected to the transmission / reception unit 320 of the subscriber-side transmission device 300 and the transmission / reception unit 420 of the subscriber-side transmission device 400 via the optical fibers 220, 221 and 222. Optical fiber 2
In FIG. 20, an optical coupler 230 is provided at a branch point to the subscriber-side transmission devices 300 and 400, and branches and combines transmission signals.

Normally, the changeover switches 130 and 140 in the station-side transmission device 100, the changeover switches 330 and 340 in the subscriber-side transmission device 300, and the changeover switches 430 and 440 in the subscriber-side transmission device 400 are all illustrated. Set to the middle a side. Thereby, the station-side transmission device 1
The transmission / reception units 110 and 00 in FIG.
0, and communication between them is performed via the optical fibers 200, 201, and 202.

At this time, the transmitting / receiving section 110 of the station side transmitting apparatus 100, the transmitting / receiving section 310 of the subscriber side transmitting apparatus 300, the transmitting / receiving section 410 of the subscriber side transmitting apparatus 400, the optical fiber 2
00, 201, 202 and the optical coupler 210,
If any of the switches fail, the changeover switches 130 and 14
0, 330, 340, 430, and 440 are all switched to the b side in the figure. As a result, the transmission / reception unit 120 in the station-side transmission device 100 faces the transmission / reception units 320 and 420, and communication between them is performed by the optical fiber 22.
0, 221 and 222.

Next, a transmission / reception diagram having the above configuration will be described. FIG. 13 is a diagram showing an example of a transmission / reception diagram in the transmission system of 1: n communication shown in FIG. 12, and shows an example in which time division multiplexing is used as a bidirectional multiplexing and subscriber multiplexing system.

Now, referring to FIG.
It is assumed that 0, 140, 330, 340, 430, and 440 are all set on the a side in the figure. As shown in FIG. 13, the transmission period T _s which is the first half of the transmission and reception repetition period T
Then, the transmission signal D1 to the subscriber side transmission device 300 and the transmission signal D2 to the subscriber side transmission device 400 are transmitted from the station side transmission device 100 as follows, and 400. First, the transmission signals D1 and D2 to be transmitted are input to the input port S1 of the station side transmission device 100 in FIG. 12 and supplied to the transmission / reception unit 110 via the changeover switch 130. 'In the transmission / reception unit 110, the transmission signals D1 and D2 are
The signal is converted into an optical signal by the transmission unit 111 and output from the input / output port C 110 to the optical fiber 200 via the optical coupler 113. 'The transmission signals D1 and D2 are branched by the optical coupler 210 and sent to the input / output port C310 of the subscriber side transmission device 300 and the input / output port C410 of the subscriber side transmission device 400 via the optical fibers 201 and 202. , Respectively. 'In the subscriber-side transmission device 300, the transmission / reception unit 310
The received transmission signal is split into D1 and D2 by an optical coupler 313, the signal is subjected to optical-electrical conversion by a receiving unit 312, and a transmission signal D1 addressed to the own device is taken out.
The signal is output to the output port R3 via the terminal 40. Similarly, in the subscriber-side transmission device 400, the transmission / reception unit 410 splits the received transmission signals D1 and D2 by the optical coupler 413,
The receiving unit 412 performs optical-to-electrical conversion, extracts the transmission signal D2 addressed to the own device, and outputs it to the output port R4 via the switch 440.

[0010] Subsequently, the reception period T _R is a second half of the transmission and reception repetition period T, the transmission signal U1 from the subscriber side transmission apparatus 300, a transmission signal U2 from the subscriber side transmission apparatus 400, Tsubonegawa transmission It is transmitted to the device 100 as follows. The transmission signal U1 to be transmitted is input to the input port S3 of the subscriber-side transmission device 300 in FIG. 12, and is supplied to the transmission / reception unit 310 via the changeover switch 330. In the transmitting / receiving section 310, the transmission signal U1 is transmitted to the transmitting section 311.
Is converted into an optical signal, and is output from the input / output port C 310 to the optical fiber 200 via the optical coupler 313. Similarly, the transmission signal U2 to be transmitted is
00 is input to the input port S4 and the changeover switch 430
Is supplied to the transmission / reception unit 410 via the. Transmitting / receiving section 410
, The transmission signal U2 is converted into an optical signal by the transmission unit 411, and is input / output port C410 via the optical coupler 413.
Are output to the optical fibers 202 and 200. Here, the transmission signals U1 and U2 are transmitted at predetermined time positions so as not to overlap each other. 'Transmission signals U1 and U2 transmitted to optical fiber 200
Are coupled by the optical coupler 210 to the station side transmission device 100
Is supplied to the input / output port C110. 'In the station side transmission device 100, the transmission / reception unit 110 splits the received transmission signals U1 and U2 by the optical coupler 113, performs optical-electric conversion by the reception unit 112, and outputs the converted signals to the output port R1 via the changeover switch 140. I do. Such an operation of “〜” corresponds to the transmission / reception repetition period T
It is repeated every time.

For the sake of simplicity, FIG. 13 omits a synchronization frame for synchronizing transmission / reception transmission signals, a control channel for designating a transmission signal position of a subscriber side transmission device and switching, and a propagation delay time in an optical fiber. ing.

Next, the transmitting / receiving unit 11 of the station side transmission device 100
0, transmission / reception section 310 of subscriber-side transmission apparatus 300, transmission / reception section 410 of subscriber-side transmission apparatus 400, optical fiber 20
A case where one of the optical couplers 0, 201, 202 and the optical coupler 210 has failed will be described. In this case, as described above, the changeover switches 130, 140, 3
30, 340, 430, and 440 are all switched to the b side in the figure.

FIG. 14 is a diagram showing an example of a transmission / reception diagram in this case, and corresponds to FIG.
In this case, in the same manner as before the switching, the communication is performed by the transmission / reception unit 120 of the station side transmission device 100, the transmission / reception unit 320 of the subscriber side transmission device 300 opposed thereto, and the transmission / reception unit 420 of the subscriber side transmission device 400. Between the optical fibers 220 and 2
21 and 222. After switching, the transmission / reception unit 1
10, 310, 410, optical fibers 200, 201, 2
02 and the optical coupler 210, repair of a failed part is performed. As a result, the downtime in the point-multipoint transmission method is reduced, and high reliability is achieved.

As described above, the conventional 1: n shown in FIG.
The transmission system of the communication includes two transmission systems, namely, the transmission / reception unit 110 of the station side transmission device 100 and the subscriber side transmission device 300.
Transmission / reception unit 310, transmission / reception unit 410 of subscriber-side transmission device 400, optical fibers 200, 201, 202, and optical coupler 210;
0 transmission / reception unit 120 and the opposing subscriber-side transmission device 300
The transmission / reception unit 320 of the subscriber side transmission device 400, the transmission system composed of the optical fibers 220, 221, 222, and the optical coupler 230 are connected to the changeover switch 130 of the station side transmission device 100, 140, the switching switches 330 and 340 of the subscriber-side transmission device 300 and the switching switches 430 and 440 of the subscriber-side transmission device 400 are used to perform the switching collectively.

[0015]

However, in such a conventional transmission system of 1: n communication, since the number of elements constituting one transmission system is relatively large, the elements constituting the transmission system to be switched to are not included. The probability of all being normal is relatively low. For example, for the sake of simplicity, the example shown in FIG. 12 shows a case where the number of transmission apparatuses on the subscriber side is two. However, when the number of transmission apparatuses on the subscriber side is large, the tendency becomes remarkable. In other words, when the number of transmission devices on the subscriber side is large, a failure occurs in one transmission system, and even if the transmission system is switched to the other transmission system at once, a failure occurs in the transmission system of the switching destination. Is more likely to occur.

As a result, there is a danger that a line that has been communicating normally may fail due to switching. Therefore, such a transmission system has a drawback that it is difficult to secure sufficient reliability especially when a large number of subscriber-side transmission devices are connected to one station-side transmission device.

The present invention has been made in view of the above-described problems, and has as its object to perform highly reliable multiplex communication between one station-side transmission device and at least one or more subscriber-side transmission devices. It is an object of the present invention to provide a transmission system of 1: n communication that can perform the communication.

[0018]

In order to solve the above-mentioned drawback, a transmission system of 1: n communication according to claim 1 is configured such that one station-side transmission device and n station-side transmission devices opposing each other via a transmission medium are used.
(Where n is an integer equal to or more than 2)
In a transmission system of 1: n communication in which time division multiplex communication is performed, a transmission signal is transmitted to the station side transmission device to the n subscriber side transmission devices opposed thereto, and the n number of subscriptions are transmitted. Two transmission / reception units for receiving transmission signals from the subscriber transmission device are provided in parallel, and reception signals from each of the two transmission / reception units are input and received from the opposing n subscriber transmission devices. Each signal includes a selection unit that selects a normal signal from the two received signals, while each of the n subscriber-side transmission devices transmits a transmission signal to the station-side transmission device opposed thereto. Transmitting, and, provided in parallel with two transmitting and receiving units for receiving the transmission signal from the station-side transmission device, respectively, and receiving the received signal from each of the two transmitting and receiving units, among the two received signals Select the normal signal It is characterized in that it comprises respectively selecting section.

In the transmission system of 1: n communication according to a second aspect of the present invention, one station-side transmission device and n (n is an integer equal to or more than 2 ) subscriber units are mutually opposed via a transmission medium. In a transmission system of 1: n communication in which time-division multiplexing communication is performed with a side transmission device, a transmission signal is transmitted to the station side transmission device to the n subscriber side transmission devices opposed thereto, In addition, two transmission / reception units that receive transmission signals from the n subscriber side transmission devices are provided in parallel, and reception signals from each of the two transmission / reception units are input, and the opposing n subscription units are input. A selection unit for selecting a normal signal of the two received signals for each of the received signals from the subscriber-side transmission device, while the n A transmitting unit for transmitting a transmission signal to a transmission device and the station side transmission; And two transmission / reception units each comprising a reception unit for receiving a transmission signal from the device, and a switching unit for inputting the transmission signal transmitted from the subscriber side to the transmission unit of one of the transmission / reception units. Prepared,
And receiving signals from each of the two transmitting and receiving units,
It is characterized by including a selection unit for selecting a normal signal of the two received signals.

The transmission system of 1: n communication according to claim 3 is the transmission system of 1: n communication according to claim 2, wherein the selection unit of the station-side transmission device includes argument of the received signal from each of the two transmitting and receiving unit provided in the
It is characterized to take a physical sum.

The transmission system of 1: n communication according to claim 4 is the transmission system of 1: n communication according to claim 1 or 2, wherein each of the n subscriber side transmission devices is The selection unit provided performs a code error detection on two reception signals from the two transmission / reception units provided in each of the n subscriber-side transmission devices, and outputs a reception signal in which no code error is detected. It is characterized in that it is selected as a normal signal.

Further, the transmission system of 1: n communication according to claim 5 is a transmission system of 1: n communication according to claim 2, wherein each switching unit of the n subscriber side transmission devices is ,
When a failure of the transmission unit of one of the two transmission / reception units provided in each of the n subscriber transmission devices is detected, the transmission signal transmitted from the subscriber is transmitted / received to the other transmission / reception unit. It is characterized in that it is inputted to the transmitting section of the section.

[0023]

According to the transmission system of 1: n communication described in claim 1, two transmission systems operate in parallel between the station-side transmission apparatus and the subscriber-side transmission apparatus, and the station-side transmission apparatus operates in parallel. On the receiving side, a normal received signal is selected from the two received signals for each received signal from the opposing subscriber-side transmission device, while the reception side of each subscriber-side transmission device selects this signal. A normal received signal is selected from the two received signals from the station-side transmission device facing the terminal. As a result, it is possible to dramatically improve reliability as compared with the conventional transmission system.

According to the transmission system of 1: n communication according to the second aspect, two transmission systems operate in parallel between the station-side transmission device and the subscriber-side transmission device, and the station-side transmission system operates. On the receiving side of the device, a normal received signal is selected from the two received signals for each received signal from the subscriber-side transmission device opposed thereto, while the receiving side of each subscriber-side transmission device is The normal received signal is selected from the two received signals from the station-side transmission device opposed thereto. On the transmitting side of each subscriber-side transmission device, a transmission signal transmitted from the subscriber side is input to one of the transmitting units of the two transmitting / receiving units. As a result, it is possible to dramatically improve reliability as compared with the conventional transmission system.

Further, according to the transmission system of 1: n communication according to the third aspect, the selection unit of the station side transmission device receives the reception signal from each of the two transmission / reception units provided in the station side transmission device. The normal reception signal is selected by taking the logical sum of For this reason, the configuration of the selection unit of the station side transmission device becomes easy.

According to the transmission system of 1: n communication described in claim 4, code error detection is performed on two reception signals from two transmission / reception units provided in the subscriber-side transmission device. , A received signal in which no code error is detected is selected as a normal signal. Thereby, a normal signal is quickly and accurately selected.

Further, according to the transmission system of 1: n communication described in claim 5, when a failure of one of the two transmitting / receiving sections of the transmitting / receiving section of the subscriber side transmitting apparatus is detected, The transmission signal transmitted from the subscriber side is input to the transmission unit of the other transmission / reception unit. That is, useless signal transmission that ensures that the transmission signal does not become a normal signal is prevented.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the first embodiment. For comparison with the conventional example shown in FIG. 12, multiplex communication is performed between one station-side transmission device and two subscriber-side transmission devices. It shows the case of performing. In FIG. 1, the same portions as those of FIG. 12 are denoted by the same reference numerals, and description thereof will be omitted. The station-side transmission device 101 includes two transmission / reception units 110 and 120 for transmitting and receiving signals to and from the opposing subscriber-side transmission devices 301 and 401, and a selection unit 150 for selecting these received signals. The transmission signal to be transmitted supplied from the input port S1 is transmitted by the transmission unit 111 of the transmission / reception unit 110 and the transmission unit 1 of the transmission / reception unit 120.
21. On the other hand, the subscriber-side transmission device 3
Reference numeral 01 includes two transmission / reception units 310 and 320 for transmitting / receiving data to / from the opposite station-side transmission device 101 and a selection unit 350 for selecting these received signals. The transmission signal to be transmitted supplied from the input port S3 is transmitted to the transmission unit 311 of the transmission / reception unit 310 and the transmission / reception unit 320.
Is supplied to both the transmission unit 321 and the transmission unit 321. Similarly, the subscriber-side transmission device 401 has two transmission / reception units 410 and 420 for transmitting and receiving to and from the opposite station-side transmission device 101.
And a selecting section 450 for selecting these received signals. Then, the transmission signal to be transmitted supplied from the input port S4 is supplied to both the transmission section 411 of the transmission / reception section 410 and the transmission section 421 of the transmission / reception section 420.

Each of the selectors 150, 350, 450
A normal signal is selected from each of the two reception inputs. The selection of the normal signal is performed, for example, by using CRC (Cycl
This is performed by selecting an error-free signal using an error detection method based on ic Redundancy check Code (cyclic redundancy code). Further, the selection units 150, 350, 450
Each selects a signal having a low frequency of error when both of the two reception inputs have an error, and selects an arbitrary reception signal when no error has occurred in both of the two reception inputs. Select input.

In the configuration shown in FIG. 1, the following two transmission systems always operate in parallel. That is, these transmission systems include the transmitting / receiving section 110 of the station side transmitting apparatus 101, the transmitting / receiving section 310 of the subscriber side transmitting apparatus 301 opposed thereto, the transmitting / receiving section 410 of the subscriber side transmitting apparatus 401, and the optical fiber 20.
0, 201, 202 and an optical coupler 210, a transmission / reception unit 120 of the station side transmission device 101, and a transmission / reception unit 32 of the subscriber side transmission device 301 opposed thereto.
0, a transmission system including the transmission / reception unit 420 of the subscriber-side transmission device 401, the optical fibers 220, 221, 222, and the optical coupler 230.

Next, a transmission / reception diagram in the above configuration will be described. FIG. 2 is a diagram showing an example of the transmission / reception diagram, and shows an example in which time division multiplex (TDM) is used as a bidirectional multiplexing and subscriber multiplexing system, similarly to FIG. 13 or FIG.

As shown in FIG. 2, the transmission and reception repetition period T
In the transmission period T _s is the first half of the transmission signals D1, D2
Is transmitted from the station-side transmission device 101 in FIG. 1 as follows, and
401. First, transmission signals D1 and D2 to be transmitted are input to an input port S1 of the station side transmission device 101 in FIG.
It is supplied to each of the transmission / reception units 110 and 120. In the transmitting and receiving unit 110, the transmission signals D1 and D2 are
The optical signal is converted into an optical signal by the
Is output from the input / output port C110 to the optical fiber 200 via Similarly, in the transmission / reception unit 120, the transmission signals D1 and D2 are converted into optical signals by the transmission unit 121, and output from the input / output port C120 to the optical fiber 220 via the optical coupler 123. Transmission signal D output from input / output port C110
1 and D2 are branched by the optical coupler 210 and the optical fiber 2
The input / output port C310 of the subscriber-side transmission device 401 and the input / output port C410 of the subscriber-side transmission device 401 are supplied to the I / O port C310 of the subscriber-side transmission device 301 via the 01 and 202, respectively. The transmission / reception unit 310 of the subscriber-side transmission device 301 receives the transmission signal D
1 and D2 are branched by the optical coupler 313, and the receiving unit 312
In addition to performing optical-to-electrical conversion, a signal D1 addressed to the own device is extracted and supplied to one input terminal of the selection unit 350. The transmission / reception unit 410 of the subscriber-side transmission device 401 splits the received transmission signals D1 and D2 by the optical coupler 413, performs optical-electric conversion in the reception unit 412, extracts the signal D2 addressed to the own device, and selects the signal D2. The signal is supplied to one input terminal of the unit 450. Similarly, transmission signals D1 and D2 output from the input / output port C120 are split by the optical coupler 230, and are connected to the input / output port C320 of the subscriber-side transmission device 301 and the subscriber side via optical fibers 221 and 222. It is supplied to the input / output port C420 of the transmission device 401, respectively. The transmission / reception unit 320 of the subscriber-side transmission device 301 splits the received transmission signals D1 and D2 by the optical coupler 323, performs optical-electrical conversion in the reception unit 322, extracts the signal D1 addressed to the own device, and selects the selection unit 350 Is supplied to the other input terminal. The transmission / reception unit 420 of the subscriber-side transmission device 401 converts the received transmission signals D1 and D2 into the optical coupler 42.
3, the signal is subjected to the optical-electrical conversion in the receiving unit 422, and the signal D2 addressed to the own device is extracted and supplied to the other input terminal of the selecting unit 450. In the subscriber-side transmission device 301, the selection unit 350 selects one of the normal signals among the transmission signals D1 supplied to the two input terminals, and outputs the selected signal via the output port R3. Similarly, in the subscriber-side transmission device 401, the selection unit 450 selects one of the normal signals from the transmission signals D2 supplied to the two input terminals, and outputs the selected signal via the output port R4.

[0033] Subsequently, the reception period T _R is a second half of the transmission and reception repetition period T, the transmission signal U1 from the subscriber side transmission apparatus 301, a transmission signal U2 from the subscriber side transmission apparatus 401, Tsubonegawa transmission It is transmitted to the device 101 as follows. First, a transmission signal U1 to be transmitted is input to the input port S3 of the subscriber-side transmission device 301 in FIG. 1 and supplied to each of the transmission / reception units 310 and 320. Similarly, a transmission signal U2 to be transmitted is input to the input port S4 of the subscriber-side transmission device 401 and supplied to each of the transmission / reception units 410 and 420. In the transmission / reception unit 310, the transmission signal U1 is converted into an optical signal by the transmission unit 311 and output from the input / output port C310 to the optical fiber 201 via the optical coupler 313. In the transmitting / receiving section 320, the transmission signal U1
Is converted into an optical signal by the transmission unit 321 and the optical coupler 3
23 to the optical fiber 22 from the input / output port C320.
1 is output. Similarly, in the transmission / reception unit 410, the transmission signal U2 is converted into an optical signal by the transmission unit 411 and output from the input / output port C410 to the optical fiber 202 via the optical coupler 413. In the transmission / reception unit 420, the transmission signal U2 is converted into an optical signal by the transmission unit 421, and output from the input / output port C420 to the optical fiber 222 via the optical coupler 423. Here, transmission signals U1, U2
Are transmitted at predetermined time positions so that they do not overlap each other on the optical fibers 200 and 220 from the subscriber side transmission devices 301 and 401 to the station side transmission device 101. Transmission signal U1 output from input / output port C310
And the transmission signal U2 output from the input / output port C410.
Are coupled by the optical coupler 210 and the optical fiber 20
0, the input / output port C11 of the station side transmission device 101
0 is supplied. Transmission / reception unit 1 of subscriber side transmission device 101
Reference numeral 10 denotes an optical coupler 113 for transmitting the received transmission signals U1 and U2.
Then, the signal is subjected to optical-electrical conversion by the receiving unit 112 and supplied to one input terminal of the selecting unit 150. Similarly, the transmission signal U1 output from the input / output port C320 and the transmission signal U2 output from the input / output port C420 are coupled by the optical coupler 230, and
It is supplied to the input / output port C120 of the optical line terminal 101. The transmission / reception unit 120 of the subscriber-side transmission device 101 branches the received transmission signals U1 and U2 by the optical coupler 123, performs optical-electrical conversion in the reception unit 122, and supplies the converted signal to the other input terminal of the selection unit 150. In the station-side transmission device 101, the selection unit 150 selects one input terminal to which a normal signal is supplied from the transmission signals supplied to the two input terminals, and transmits the normal signal via the output port R1. Output. These operations are repeated every transmission / reception repetition period T.

For simplicity, FIG. 2 omits a synchronization frame for synchronizing transmission / reception transmission signals, a control channel for specifying a transmission signal position of a subscriber-side transmission device, and a propagation delay time in an optical fiber. .

According to the first embodiment, two transmission systems operate simultaneously and in parallel between the station-side transmission device 101 and the subscriber-side transmission devices 301 and 401. In the station side transmission device 101, one normal reception signal out of two reception signals is selected by the selection unit 150 for each reception signal from the subscriber side transmission devices 301 and 401 opposed thereto, while each subscriber side transmission device The transmission device 301 or 401 selects one normal received signal from the two received signals from the station-side transmission device 101 opposed thereto by the selector 350 or 450. As a result, in the conventional system, since the transmission system in which a failure has occurred is switched to the other transmission system at a time, it is necessary that all elements constituting the transmission system to be switched to be all normal. On the other hand, in the present invention, in two transmission systems operating in parallel, if at least one of the two elements is normal for each element constituting the transmission system, communication is performed normally, so reliability is dramatically improved. It is possible to improve. In the first embodiment, the changeover switch and the switch control in the conventional system are not required.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the second embodiment. For comparison with the conventional example shown in FIG. 12, multiplex communication is performed between one station-side transmission device and two subscriber-side transmission devices. It shows the case of performing. In addition,
3, the same parts as those in FIGS. 1 and 12 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, the station-side transmission device 101 comprises transmission / reception units 110 and 120 for transmitting and receiving signals to and from the opposing subscriber-side transmission devices 302 and 402, and 150 for selecting a reception signal. On the other hand, the subscriber-side transmission device 302
Are two transmission / reception units 310 and 320 for transmitting and receiving to and from the opposite station-side transmission device 101, a switching unit 330 for switching the transmission signal, and a selection unit 35 for selecting the reception signal.
It consists of 0. Similarly, the subscriber-side transmission device 402 includes transmission / reception units 410 and 420 for transmitting / receiving data to / from the opposite station-side transmission device 101 and a switching unit 43 for switching transmission signals.
0 and a selection section 450 for selecting a received signal.

The transmitting / receiving section 110 of the station side transmission apparatus 101
Optical fibers 200, 201, 202 and optical coupler 21
0, the transmission / reception unit 31 of the subscriber-side transmission device 302
0, and the transmission / reception unit 410 of the subscriber-side transmission device 402. On the other hand, the transmission / reception unit 12 of the station side transmission device 101
0 is the transmission / reception unit 3 of the subscriber-side transmission device 302 via the optical fibers 220, 221, 222 and the optical coupler 23.
20, and the transmission / reception unit 420 of the subscriber-side transmission device 402
Connected to

Here, a specific configuration of each section will be described with reference to FIGS. FIG.
Is a diagram for explaining the configuration of the transmission / reception unit 1 of the station side transmission apparatus 101, as shown in FIG.
10 receiving unit 112 and receiving unit 122 of transmitting / receiving unit 120
And outputs the logical sum of these to the terminal R1. Two transmission / reception units 310 and 320 and two transmission / reception units 4 provided in the subscriber side transmission devices 302 and 402, respectively.
10, 420 each transmit only one of the transmission signals.

Therefore, the subscriber-side transmission devices 302, 4
02 to the station side transmission apparatus 101 from the transmission signals U1, U2
Is input to only one of the two input terminals of the selection unit 150. Therefore, the transmission signals U1 and U2 can be output by ORing the two inputs. As a result, without switching the input for each transmission signal,
The selection function can be realized with a simple configuration.

FIG. 8 is a block diagram showing a schematic configuration of the selection section 350. As shown in FIG.
12 and 322 are input to a changeover switch 353, and the error detection units 351 and 35 are respectively provided.
2 is input. Error detection sections 351 and 352 detect the presence or absence of a code error in the input signal, and output error detection signals a and b to control section 354, respectively. As a code error detection method, as described in the first embodiment, the CRC
Error detection method.

The control section 354 controls the changeover switch 353 based on the information represented by the error detection signals a and b.
Here, an example of a switching method of the switch 353 will be described. First, the changeover switch 353 is controlled based on the information represented by the error detection signals a and b so as to select a signal in which no error is detected (normal signal). However, if an error is detected in both of the two received inputs,
Change-over switch 3 to select a signal with a low error frequency
53 is controlled. If no error has occurred in either of the two reception inputs, the changeover switch 353 is controlled to select any one of the reception inputs.

In general, the receiving section 312 of the transmission apparatus,
322 often has an error detection function. In such a case, the receiving units 312 and 322 send the control unit 354
An error detection signal may be directly input to the selector 350.
In addition, it is not necessary to provide the error detection units 351 and 352. The configuration and operation of the selection unit 450 are the same as those of the selection unit 350
Therefore, the description is omitted.

FIG. 9 is a block diagram showing a schematic configuration of the switching section 330. As shown in FIG. 9, the switching section 330 includes a switch 331 and a control section 332. In the switching unit 330, the control unit 332
The failure detection signals A1 and A2 output from the transmission units 311 and 321 are received. When a failure detection signal is input from one of the transmission units, the control unit 332 switches and controls the switch 331 so as to supply a signal to the other normal transmission unit. In addition, as the failure detection signal, for example, an electric / optical conversion unit of a transmission unit, that is, detection of monitor light of a laser diode can be used. Specifically, when the laser diode fails during communication and the light output is cut off, monitor light is no longer detected, and a failure in the transmission unit is detected. The configuration and operation of the switching unit 430 are the same as those of the switching unit 33 described above.
Since it is the same as 0, its description is omitted.

FIG. 10 is a block diagram showing a schematic configuration of the station-side transmission device 101. As shown in FIG.
The control unit 160 of the station side transmission device 101
With the outputs of the receiving unit 112 and the receiving unit 122 of the transmitting / receiving unit 120 as inputs, the reception signals from the plurality of subscriber-side transmission devices that are time-division multiplexed are monitored for each of the subscriber-side transmission devices. Here, the monitoring operation by the control unit 160 will be specifically described. For example, two transmission / reception units 310, 320, and 410 of the subscriber-side transmission devices 302 and 402, respectively.
At 420, while the transmitting units 311 and 411 are operating, the transmitting / receiving unit 31 of the subscriber side transmitting apparatus 302 is operated.
0, an optical coupler 313, an optical fiber 201 or 200, an optical coupler 210, and an optical coupler 113 in the transmitting / receiving unit 110 of the optical line terminal 101.
Alternatively, it is assumed that one of the receiving units 112 has failed.

In this case, in the output of the receiving unit 112,
The transmission signal from the subscriber-side transmission device 302 is in a state of “disconnection” or “frequent code errors”. When the control unit 160 detects a state in which the transmission signal from the subscriber side transmission device 302 in the receiving unit 112 is “disconnected” or “frequent occurrence of code errors”, the control unit 160 transmits the switching signal S31 to the transmitting unit 111 of the transmitting / receiving unit 110. To the transmitting unit 121 of the transmitting / receiving unit 120. Thereby, the transmission unit 111 and the transmission unit 121
Multiplexes the switching signal S31 with the downlink transmission signal and transmits it.

Similarly, the transmitting section 321 or the optical coupler 32 in the transmitting / receiving section 320 of the subscriber-side transmission apparatus 302
3, optical fiber 221 or 220, optical coupler 23
0, one of the optical coupler 123 and the receiving unit 122 in the transmitting / receiving unit 120 of the station-side transmission device 101 has failed, and the output of the receiving unit 122 indicates that the subscriber-side transmission device 3
02 is "disconnected" or "frequent code errors"
When the control unit 160 detects that
32, the transmitting unit 111 of the transmitting / receiving unit 110 and the transmitting / receiving unit 12
Multiplexed with the downlink transmission signal via the transmission unit 121 of “0” and transmitted.

Here, the switching section 330 will be described again. FIG. 11 is a block diagram illustrating a schematic configuration of the switching unit 330. The control unit 330 includes the configuration illustrated in FIG.
And the configuration shown in FIG. Control unit 33 of switching unit 330
3 is a switching signal S output from the receiving units 312 and 322
31, S32 are received. The control unit 333 controls the switching signal S
When 31 is input, the switch 331 is controlled to transmit a transmission signal via the transmission unit 321. Further, when the switching signal S32 is input, the control unit 333
The changeover switch 331 is controlled so as to transmit a transmission signal via the transmission unit 311. When the transmission signal from the subscriber-side transmission device 402 is disconnected or a state in which many code errors occur, similar switching control is performed using the switching signals S41 and S42 corresponding to the switching signals S31 and S32. You.

Next, a transmission / reception diagram in the above configuration will be described. FIG. 4 is a diagram showing an example of the transmission / reception diagram, as in FIG. 2, showing an example in which time division multiplexing is used as a bidirectional multiplexing and subscriber multiplexing method.
However, the transmission period T which is the first half of the transmission / reception repetition period T
_{In s} , the same communication operation as in FIG. 2 is performed.
The description is omitted. Operational difference from the first embodiment and the second embodiment in the transmission period T _s, in place of the subscriber side transmission apparatus 301, 401, the subscriber side transmission apparatus 302,
It is only at the point where 402 is activated.

[0050] In this embodiment, as shown in FIG. 4, the reception period T _R is a second half of the transmission and reception repetition period T, the transmission signal U1 from the subscriber side transmission apparatus 302, from the subscriber side transmission apparatus 402 The transmission signal U2 is transmitted to the station side transmission device 101 as follows.

First, the transmission signal U1 to be transmitted is input to the input port S3 of the subscriber-side transmission device 302 in FIG. 3, and is input to one of the transmission / reception unit 310 and the transmission / reception unit 320 via the switching unit 330. Is done. In FIG. 3, the switching unit 330 has been switched to the “a” side, and the transmission signal U1 is supplied to the transmission / reception unit 310. In the transmission / reception unit 310, the transmission signal U1 is converted into an optical signal, and is output from the input / output port C310 to the optical fiber 201 via the optical coupler 313.

On the other hand, a transmission signal U2 transmitted from the subscriber side is input to the input port S4 of the subscriber side transmission device 402, and this transmission signal U2 is transmitted to the transmission / reception unit 410 or 420 by the switching unit 430. Is entered. FIG.
In FIG. 4 and FIG. 4, the switching unit 430 is switched to the “a” side, so that the transmission signal U2 is input to the transmission unit 410. In the transmission / reception unit 410, the transmission signal U2 is converted into an optical signal by the transmission unit 411, and output from the input / output port C410 to the optical fiber 202 via the optical coupler 413.

The input / output port C of the subscriber-side transmission device 302
The transmission signal U1 output from 310 and U2 output from the input / output port C410 of the subscriber-side transmission device 402 are combined by the optical coupler 210 and input to the input / output port C110 of the station-side transmission device 101. . Note that no signal is output from the input / output port C320 of the subscriber-side transmission device 302 and the input / output port C420 of the subscriber-side transmission device 402.

The input / output port C11 of the station side transmission device 101
The transmission signals U1 and U2 input to 0 are input to the reception unit 112 via the optical coupler 113 in the transmission and reception unit 110. The transmission signals U1 and U2 are converted into electric signals in the reception unit 112 and output to the selection unit 150. On the other hand, since no transmission signal is input to the input / output port C120,
The output from the receiving unit 122 to the selecting unit 150 is a no signal. The selector 150 selects the normal signal by taking the logical sum of the two received inputs for each of the transmission signals U1 and U2, and outputs the selected signal to the output port R1. In this case, the transmission signals U1 and U2 are input only from the receiving unit 112, and there is no signal from the receiving unit 122, so that the signal from the receiving unit 112 is output to the output port R1.

Next, as shown in FIG. 5, transmission / reception in the case where the switching unit 330 of the subscriber-side transmission device 302 is switched to the a-side and the switching unit 430 of the subscriber-side transmission device 402 is switched to the b-side. The operation will be described with reference to FIGS. FIG. 6 is a diagram showing an example of the transmission / reception diagram in the state shown in FIG. 5, and shows an example in which time division multiplexing is used as the bidirectional multiplexing and subscriber multiplexing system, as in FIG.

As is clear from FIG. 6, the station-side transmission device 1
The operation in the transmission period T _S of No. 01 is the same as the operation shown in FIG. On the other hand, the reception period T _R, the transmission signal from the subscriber side transmission apparatus 302 U1
And the transmission signal U2 from the subscriber side transmission device 402,
The data is transmitted to the optical line terminal 101 as follows.

First, a transmission signal U1 transmitted from the subscriber side is input to the input port S3 of the subscriber-side transmission device 302, and this transmission signal U1 is
This is input to the transmission unit 310 on the a side. In the transmission / reception unit 310, the transmission signal U1 is converted into an optical signal by the transmission unit 311 and is input / output port C31 via the optical coupler 313.
Output from 0. The transmission signal U1 output here is
Via the optical fiber 201, the optical coupler 210, and the optical fiber 200, the input / output port C of the optical line terminal 101
Input to 110. The transmission signal U1 input to the input / output port C110 is converted into an electric signal in the transmission / reception unit 110 and output to the selection unit 150.

On the other hand, a transmission signal U2 transmitted from the subscriber side is input to the input port S4 of the subscriber side transmission device 402, and this transmission signal U2 is transmitted through the switching unit 430 to b
Is input to the transmitting / receiving section 420 on the side. In the transmission / reception unit 420, the transmission signal U2 is converted into an optical signal by the transmission unit S421, and is input / output port C4 via the optical coupler 423.
20. The transmission signal U2 output here
Is input to the input / output port C120 of the optical line terminal 101 via the optical fiber 222, the optical coupler 230, and the optical fiber 220. The transmission signal U2 input to the input / output port C120 is converted into an electric signal in the transmission / reception unit 120 and output to the selection unit 150. Since no signal is output from the input / output port C320 of the subscriber-side transmission device 302 and the input / output port C410 of the subscriber-side transmission device 402, the transmission / reception unit 110 sends the selection unit 15
0 is not output to the transmission signal U2. Similarly, transmission signal U1 is not output from transmission / reception section 120 to selection section 150.

The selector 150 selects a normal signal from the two reception inputs for each of the transmission signals U1 and U2, and outputs it to the output port R1. That is, the transmission signal U
1, the transmission signal U
As for 2, the signal from the transmission / reception unit 120 is selected and output to the output port R1. For the sake of simplicity, in FIGS. 4 and 6, a synchronization frame for synchronizing transmission and reception transmission signals,
A control channel for designating a position of a transmission signal of a subscriber side transmission device and switching the switch, and a propagation delay time in an optical fiber are omitted.

According to the second embodiment, two transmission systems simultaneously operate in parallel between the station-side transmission device 101 and the subscriber-side transmission devices 302 and 402. In the station-side transmission device 101, one normal reception signal out of two reception signals is selected by the selection unit 150 for each reception signal from the subscriber-side transmission devices 302 and 402 opposed thereto, while each subscriber side The transmission device 302 or 402 selects one normal received signal from the two received signals from the station-side transmission device 101 opposed thereto by the selection unit 350 or 450. Further, in the switching units 330 and 430 of the subscriber side transmission devices 302 and 402, the transmission units that receive the transmission signals U1 and U2 transmitted from the subscriber side are switched and controlled.

From the above, as in the first embodiment, in two transmission systems operating in parallel, if at least one of the two components of the transmission system is normal, communication is performed normally. Therefore, it is possible to dramatically improve the reliability. The selection unit 150
Is transmitted to only one of the two input terminals U1,
U2 is input, and the transmission signals U1 and U2 are output by ORing both inputs. Therefore, there is no need to switch the input for each transmission signal, and the selection function can be realized with a simple configuration.

Further, the subscriber-side transmission devices 302 and 402
In one of the switching units 330 and 430, switching control is performed such that transmission signals U1 and U2 transmitted from the subscriber side are input to the other transmission units when one transmission unit of the own device fails. . For this reason, it is possible to prevent useless signal transmission that causes “disconnection” or “frequent occurrence of code errors”.

In the first and second embodiments, the number of subscriber-side transmission devices is described as "2" for convenience of explanation. However, the number may be "3" or more. Those skilled in the art can easily estimate by analogy that the present invention can also be applied to a configuration in which one station-side transmission device is connected to one subscriber-side transmission device, that is, a point-to-point transmission, where the number of devices is "1". it can. Furthermore, although the configuration of each unit has been specifically described, the present invention is not limited to the configurations described in the first and second embodiments.

[0064]

According to the present invention described above, the two transmission systems operate in parallel between the station-side transmission device and the subscriber-side transmission device, and at the receiving side of the station-side transmission device,
For each signal received from the opposite subscriber-side transmission device,
While a normal reception signal is selected from the two reception signals, a normal reception signal is selected from the two reception signals from the opposite station transmission device on the receiving side of each subscriber transmission device. Is done. Therefore, in the conventional method in which the transmission system in which a failure has occurred is switched to the other transmission system at once, there is a risk that a line that has been communicating normally may fail due to switching, and the elements constituting the transmission system to be switched to may be lost. In contrast to the necessity of all one being normal, in the present invention, in two transmission systems operating in parallel, communication is performed if at least one of the two elements is normal for each element constituting the transmission system. Since it is performed normally, there is an effect that it is possible to dramatically improve reliability.

[0065] Further, selection of Tsubonegawa transmission apparatus, simple of selecting the successful reception signal by taking a logical sum of the received signal from each of the two transmitting and receiving unit provided in the station side transmission unit With the configuration, there is an effect that the selection unit can be easily configured (claim 3).
Further, code error detection is performed on two received signals from two transmission / reception units provided in the subscriber-side transmission device, and a received signal in which no code error is detected is selected as a normal signal. Therefore, there is an effect that a normal signal can be selected quickly and accurately (claim 4). further,
Of the two transmitting / receiving units provided in the subscriber-side transmission device,
When a failure of the transmitting unit of one transmitting / receiving unit is detected, the transmission signal transmitted from the subscriber side is input to the transmitting unit of the other transmitting / receiving unit. Therefore, there is an effect that it is possible to prevent useless signal transmission that ensures that a transmission signal does not become a normal signal (claim 5).

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a communication system to which a transmission system of 1: n communication according to a first embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating an example of a transmission / reception diagram of the system.

FIG. 3 is a block diagram showing a schematic configuration of a communication system to which a transmission system of 1: n communication according to a second embodiment of the present invention is applied.

FIG. 4 is a diagram showing an example of a transmission / reception diagram of the system.

FIG. 5 is a block diagram for explaining the operation of the system.

FIG. 6 is a diagram showing an example of a transmission / reception diagram of the system.

FIG. 7 is a diagram showing a schematic configuration of a selection unit 150.

FIG. 8 is a block diagram illustrating a schematic configuration of a selection unit 350.

FIG. 9 is a block diagram illustrating a configuration of a switching unit 330.

FIG. 10 is a block diagram showing a schematic configuration of a station side transmission device 101.

11 is a block diagram for explaining a configuration of a switching unit 330. FIG.

FIG. 12 is a block diagram showing a schematic configuration of a communication system to which a conventional transmission system of 1: n communication is applied.

FIG. 13 is a diagram showing an example of a transmission / reception diagram of the system.

FIG. 14 is a diagram showing an example of a transmission / reception diagram of the system.

[Explanation of symbols]

101 ...
... Station-side transmission devices 110, 120, 310, 320, 410, 420 ...
... Transceiver units 111, 121, 311, 321, 411, 421 ...
… Transmission units 112, 122, 312, 322, 412, 422…
… Receiving unit 150, 350, 450…
... Selection units 301, 302, 401, 402 ...
... Subscriber side transmission devices 330, 430 ...
… Switching unit

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiro Takikawa 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-5-63698 (JP, A) JP-A-57-42248 (JP, A) JP-A-63-269637 (JP, A) Japanese Utility Model Application Sho-63-55639 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04Q 11 / 04 H04M 3/56 H04Q 3/52 101

Claims (5)

(57) [Claims] A time-division multiplex communication is performed between one station-side transmission device and n (n is an integer equal to or more than 2 ) subscriber-side transmission devices facing each other via a transmission medium. In the transmission method of n communications, a transmission signal to the station transmission device is transmitted to the n subscriber transmission devices opposed thereto, and a transmission signal from the n subscriber transmission devices is transmitted. Are provided in parallel with each other, and receive signals from each of the two transmit / receive units are input, and for each of the receive signals from the n opposite subscriber-side transmission devices, the two receive signals are received. A transmission unit that transmits a transmission signal to the station-side transmission device opposed to each of the n-side subscriber transmission devices, and Two transmission / reception units that receive transmission signals from transmission equipment A transmission unit for 1: n communication, comprising a selection unit for inputting a reception signal from each of the two transmission / reception units and selecting a normal signal from the two reception signals. . 2. Time-division multiplex communication is performed between one station-side transmission device and n (n is an integer equal to or more than 2 ) subscriber-side transmission devices facing each other via a transmission medium. In the transmission method of n communications, a transmission signal to the station transmission device is transmitted to the n subscriber transmission devices opposed thereto, and a transmission signal from the n subscriber transmission devices is transmitted. Are provided in parallel with each other, and receive signals from each of the two transmit / receive units are input, and for each of the receive signals from the n opposite subscriber-side transmission devices, the two receive signals are received. A transmission unit that transmits a transmission signal to the station-side transmission device facing each of the n subscriber-side transmission devices while providing a selection unit that selects a normal signal among the signals; A receiver that receives the transmission signal from the transmission device. Two transmission / reception units are provided in parallel, and a switching unit for inputting a transmission signal transmitted from the subscriber side to the transmission unit of one of the transmission / reception units is provided, and reception from each of the two transmission / reception units is provided. A transmission system for 1: n communication, comprising a selection unit for inputting a signal and selecting a normal signal from the two received signals. 3. The transmission unit according to claim 2, wherein the selection unit of the station-side transmission device calculates a logical sum of signals received from each of the two transmission / reception units of the station-side transmission device. 1: transmission system for n communication. 4. The selector provided in each of the n subscriber-side transmission devices is configured to receive two reception signals from two transmission / reception units provided in each of the n subscriber-side transmission devices. 3. The transmission method of 1: n communication according to claim 1, wherein a code error is detected for the received signal, and a received signal in which no code error is detected is selected as a normal signal. 5. The transmission unit of one of the two transmission / reception units provided in each of the n subscriber-side transmission devices, the switching unit of each of the n subscriber-side transmission devices. 3. The transmission method of 1: n communication according to claim 2, wherein when a failure is detected, a transmission signal transmitted from the subscriber side is input to a transmission unit of the other transmission / reception unit.