JPH0591116A - Looped data transmission system - Google Patents

Abstract

PURPOSE:To set freely the structure of one multi-frame in the looped data transmission system. CONSTITUTION:A one-multi-frame consists of 20 STM-1 frames F(1)-F(20). rows (1-9) and time slots (1-9) of the STM-1 frame are an SOH (section overhead) and a virtual C4 is set to the rows (1-9) and time slots (11-270) of the STM-1 frame. A prescribed time slot in the virtual C4 is used for a multi-frame synchronization pattern and time slots of an optional number are used for a house keeping channel and the remaining time slots are used for a service channel.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a loop type data transmission system, and more particularly to a data transmission system in a loop network system.

[0002]

2. Description of the Related Art Conventionally, in a loop network system, one master node and a plurality of slave nodes are connected on a loop via a transmission line. When data transmission is performed in this loop, an STM-1 frame, which is composed of 4 or 24 270 (octet) × 9 (row) time slots, is used for one multiframe.

The STM-1 frame includes SOH (section overhead) containing control information of the frame and SOH.
VC4 whose start position is specified by the AU pointer in
It consists of VC4 is a P containing control information of VC4.
It is composed of OH and C4 which uses the H4 pointer in POH as a multi-frame synchronization pattern. That is, for data transmission in the loop, the H4 pointer in the POH forming the VC4 in the STM-1 frame is used as a multiframe synchronization pattern, and the C4 time slot in the STM-1 frame is used as a service channel for storing data and the like. Time division multiplexed frames are used.

The master node generates the above time division multiplexed frame, drops and inserts the line data connected to the own node into the service channel (C4) of this time division multiplexed frame, and then transmits the time division multiplexed frame. It is being sent to the next slave node via the path.

The slave node performs subordinate synchronization with the time division multiplex frame received via the transmission path, drops and inserts the line data connected to the own node into the service channel of this time division multiplex frame, and then performs the time division multiplex. The frame is sent to the next slave node or master node via the transmission path.

Further, when the master node receives the time division multiplex frame via the transmission line, it corrects the delay between the time division multiplex frame generated and transmitted by itself and the received time division multiplex frame. Therefore, loop delay correction is performed.

In such a conventional loop network system, the VC4 in the STM-1 frame is recommended by CCITT recommendation.
H4 pointer in POH that composes 2 bits or 5
Since the H4 pointer is a bit and the H4 pointer is used as a multi-frame synchronization pattern, there is a disadvantage that only one SMT-1 frame having 4 or 24 multi-frames can be realized.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a loop type data transmission system in which the structure of one multiframe can be freely set.

[0009]

A loop type data transmission system according to the present invention uses a time division multiplex frame composed of one or more STM-1 frames in which a master node and a plurality of slave nodes are connected in a loop through a transmission line. A loop-type data transmission system for performing data transmission between the master node and the plurality of slave nodes, the STM-
C4 including data information in one frame is connected to the own node and a frame synchronization pattern inserting means for inserting a frame synchronization pattern for synchronizing the virtual C4 into the virtual C4 fixedly arranged at a predetermined position. Data insertion means for exchanging data between the line and the virtual C4, and the time division multiplexed frame including the virtual C4 into which the frame synchronization pattern is inserted and the data is exchanged on the transmission path. The master node is provided with transmitting means for transmitting, and loop correcting means for correcting a delay between the time division multiplexed frame transmitted on the transmission path and the time division multiplexed frame received via the transmission path, The virtual C4 of the time division multiplexed frame received via the transmission path
Data insertion means for exchanging data between the virtual C4 and a line connected to the own node in a subordinate synchronization with the frame synchronization pattern inserted in the virtual C4, and the data insertion means inserted in the virtual C4 of the time division multiplex frame. The frame synchronization pattern inserting means for inserting the frame synchronization pattern into the virtual C4 for which the data has been exchanged by the data inserting means, and the frame synchronization pattern has been inserted and the data has been exchanged. A transmitting means for transmitting the time division multiplexed frame including the virtual C4 onto the transmission path is provided in each of the plurality of slave nodes.

In another loop type data transmission system according to the present invention, a master node and a plurality of slave nodes are connected in a loop through a transmission line, and a time division multiplex frame composed of one or more STM-1 frames is used. A loop-type data transmission system for performing data transmission between the master node and the plurality of slave nodes, the STM comprising:
-1 Frame synchronization pattern inserting means for inserting a frame synchronization pattern for synchronizing C4 into C4 including data information in one frame, and data exchange between the line connected to the own node and the C4. Data inserting means for performing, a transmitting means for transmitting the time division multiplexed frame including the C4 into which the frame synchronization pattern has been inserted and the data has been exchanged on the transmission path, and the time for transmitting on the transmission path. A loop correction unit that corrects a delay between the division multiplex frame and the time division multiplex frame received via the transmission line is provided in the master node, and the loop correction unit of the time division multiplex frame received via the transmission line is provided. Data insertion for exchanging data between the C4 and a line connected to its own node in subordinate synchronization with the frame synchronization pattern inserted in the C4 And a frame synchronization pattern inserting means for inserting the frame synchronization pattern inserted in the C4 of the time division multiplex frame into the C4 to which the data is exchanged by the data inserting means, and the frame synchronization pattern. And a transmission means for transmitting the time division multiplexed frame including the C4 in which the data has been exchanged and the data has been transmitted and received on each of the plurality of slave nodes.

[0011]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a master node according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a slave node according to an embodiment of the present invention, and FIG. It is a block diagram showing the system configuration of one example. In these figures, the master node A and the slave nodes B1 to BN are connected in a loop via a transmission line C to form a loop network system (see FIG. 3).

The STM-1 frame synchronization detector (hereinafter referred to as the frame synchronization detector) 1 of the master node A is a transmission line C.
When the reception data (RD) is received from STM-, the reception clock (RC) is extracted from the reception data.
Received frame pulse (RF
P) is generated. The frame synchronization detection unit 1 sends the received data, the received clock, and the received frame pulse to the SOH terminating unit 2.

The SOH terminating unit 2 terminates the SOH of the STM-1 frame, which is the reception data, by the reception data, the reception clock and the reception frame pulse received from the frame synchronization detection unit 1. When the SOH of the STM-1 frame is terminated, the SOH terminating unit 2 receives the reception data excluding the SOH, that is, the virtual C4 fixedly arranged at a predetermined position of the STM-1 frame, the reception clock, and the reception frame pulse. It is sent to the multi-frame synchronization detector 3.

Upon receiving the reception data, the reception clock, and the reception frame pulse from the SOH terminating unit 2, the multiframe synchronization detection unit 3 performs multiframe synchronization from the multiframe synchronization pattern stored in a predetermined time slot in the virtual C4. Detect and receive multi-frame pulse (RMF
P) is generated. When the multi-frame synchronization detection unit 3 generates the reception multi-frame pulse, it sends the reception data, the reception clock, the reception frame pulse, and the reception multi-frame pulse to the loop delay correction unit 6.

The clock generator 4 is a master clock (MC) of the loop network system according to an embodiment of the present invention.
K) to generate a frame pulse /
It is sent to the multi-frame pulse generator (hereinafter referred to as pulse generator) 5.

When the pulse generator 5 receives the master clock from the clock generator 4, the transmission clock (SC) from the master clock, the transmission frame pulse (SFP) indicating the frame synchronization pattern position of the STM-1 frame, and the virtual clock. A transmission multi-frame pulse (SMFP) indicating a multi-frame synchronization pattern position stored in a predetermined time slot in C4 is generated. The pulse generator 5 sends the transmission clock, the transmission frame pulse, and the transmission multi-frame pulse to the loop delay correction unit 6.

The loop delay correction unit 6 receives the received data, the received clock, the received frame pulse, and the received multiframe pulse from the multiframe synchronization detection unit 3, and the transmitted clock, the transmitted frame pulse, and the transmitted multiframe pulse from the pulse generation unit 5. The loop delay correction for the virtual C4 is performed by When the loop delay correction unit 6 performs the loop delay correction on the virtual C4, the transmission data (S
D), the transmission clock, the transmission frame pulse, and the transmission multi-frame pulse are sent to the add / drop unit 7.

The add / drop unit 7 receives the transmission data from the loop delay correction unit 6, the transmission clock, the transmission frame pulse, and
When receiving the transmission multi-frame pulse, the data from the line connected to the service channel connection unit 8 is dropped and added to the service channel in the virtual C4 in the transmission data. Further, the add / drop unit 7 receives data from the line connected to the housekeeping channel connection unit 9 for the housekeeping channel in the virtual C4 in the transmission data from the loop delay correction unit 6 (maintenance information, monitoring information, etc.). )
Branch and insert.

When the add / drop unit 7 drops / adds data to the service channel and the housekeeping channel in the virtual C4, the send / drop data is dropped and added to the service channel and the housekeeping channel.
The transmission clock, the transmission frame pulse, and the transmission multi-frame pulse are combined into a multi-frame synchronization pattern insertion unit 10
To send to.

Upon receiving the transmission data, the transmission clock, the transmission frame pulse, and the transmission multi-frame pulse from the add / drop unit 7, the multi-frame synchronization pattern insertion unit 10 receives the transmission data based on the transmission multi-frame pulse. The multi-frame synchronization pattern is inserted into a predetermined time slot for the multi-frame synchronization pattern in the virtual C4.
The multi-frame synchronization pattern insertion unit 10 sends the transmission data in which the multi-frame synchronization pattern is inserted in a predetermined time slot, the transmission clock, and the transmission frame pulse to the SOH addition unit 11.

The SOH adding unit 11 transmits the transmission data from the multi-frame synchronization pattern inserting unit 10, the transmission clock,
Transmission data by transmission frame pulse (virtual C4)
To the STM-1 frame synchronization pattern adding unit (hereinafter referred to as the frame synchronization pattern adding unit) 12 and sends the SOH-added transmission data, the transmission clock, and the transmission frame pulse.

The frame synchronization pattern adding section 12 adds the frame synchronization pattern to the SOH of the transmission data by the transmission data from the SOH adding section 11, the transmission clock, and the transmission frame pulse, and transmits the transmission data to which the frame synchronization pattern is added. It is sent to the slave node B1 via the transmission line C.

Therefore, by configuring the master node A as described above, one multiframe has 20 S
A predetermined time slot in the virtual C4, which is composed of TM-1 frames and whose row and time slot is the virtual C4, is a multi-frame synchronization pattern, and an arbitrary number of time slots in the virtual C4. As the housekeeping channel and the remaining time slots in the virtual C4 as the service channel can be generated. Also, after the line data connected to the service channel connection unit 8 of the own node is dropped into the service channel, it can be sent to the next slave node B1 via the transmission line C. Further, in the master node A, the delay between the received time division multiplex frame and the time division multiplex frame generated in the self node can be corrected by the loop delay correction unit 6.

When the frame synchronization detector 1 of the slave node B1 receives the reception data from the transmission line C, it extracts the reception clock from the reception data and detects the STM-1 frame synchronization to generate the reception frame pulse.
The frame synchronization detection unit 1 sends the received data, the received clock, and the received frame pulse to the SOH terminating unit 2.

The SOH terminating unit 2 terminates the SOH of the STM-1 frame, which is the received data, by the received data, the received clock and the received frame pulse received from the frame synchronization detecting unit 1. When the SOH of the STM-1 frame is terminated, the SOH terminating unit 2 receives the reception data excluding the SOH, that is, the virtual C4 fixedly arranged at a predetermined position of the STM-1 frame, the reception clock, and the reception frame pulse. It is sent to the multi-frame synchronization detector 3.

The multiframe synchronization detection unit 3 uses the reception data, the reception clock, and the reception frame pulse received from the SOH termination unit 2 to perform multiframe synchronization from the multiframe synchronization pattern stored in a predetermined time slot in the virtual C4. Detect and generate received multi-frame pulses. When the multi-frame synchronization detection unit 3 generates the reception multi-frame pulse, it sends the reception data, the reception clock, the reception frame pulse, and the reception multi-frame pulse to the add / drop unit 7.

When the add / drop unit 7 receives the received data, the received clock, the received frame pulse, and the received multiframe pulse from the multiframe synchronization detecting unit 3, the add / drop unit 7 receives the received data, the received data, the received clock, the received multiframe pulse, The data from the line connected to the service channel connection unit 8 is dropped and added. Also, the add / drop unit 7 drops and inserts data (maintenance information, monitoring information, etc.) from the line connected to the housekeeping channel connection unit 9 into the housekeeping channel in the virtual C4 in the received data.

When the add / drop unit 7 drops / adds data to the service channel and the housekeeping channel in the virtual C4, it sends the receive clock with the received data dropped and added to the service channel and the housekeeping channel as the send data. As a clock
The reception frame pulse is transmitted as a transmission frame pulse, and the reception multiframe pulse is transmitted as a transmission multiframe pulse to the multiframe synchronization pattern insertion unit 10, respectively.

Upon receiving the transmission data, the transmission clock, the transmission frame pulse, and the transmission multi-frame pulse from the add / drop unit 7, the multi-frame synchronization pattern inserting unit 10 receives the transmission data based on the transmission multi-frame pulse. The multi-frame synchronization pattern is inserted into a predetermined time slot for the multi-frame synchronization pattern in the virtual C4.
The multi-frame synchronization pattern insertion unit 10 sends the transmission data in which the multi-frame synchronization pattern is inserted in a predetermined time slot, the transmission clock, and the transmission frame pulse to the SOH addition unit 11.

The SOH adding unit 11 transmits the transmission data from the multi-frame synchronization pattern inserting unit 10, the transmission clock,
Transmission data by transmission frame pulse (virtual C4)
SOH is added to the frame synchronization pattern adding section 12 and the transmission data to which the SOH is added, the transmission clock, and the transmission frame pulse are sent to the frame synchronization pattern adding section 12.

The frame synchronization pattern addition unit 12 adds the frame synchronization pattern to the SOH of the transmission data by the transmission data from the SOH addition unit 11, the transmission clock, and the transmission frame pulse, and transmits the transmission data to which the frame synchronization pattern is added. It is sent to the slave node B2 via the transmission line C.

Therefore, by configuring the slave node B1 as described above, one multiframe is composed of 20 STM-1 frames, and the row and time slot of this STM-1 frame is set to a virtual C4. Virtual C
4 into a time-division multiplex frame having a predetermined time slot as a multiframe synchronization pattern, an arbitrary number of time slots in the virtual C4 as a housekeeping channel, and remaining time slots in the virtual C4 as a service channel. After subordinate synchronization, the line data connected to the service channel connection unit 8 of the own node is dropped and inserted into the service channel, and then can be transmitted to the next slave node B2 via the transmission line C. The other slave nodes B2 to BN have the same configuration as the slave node B1 and the operation thereof is also the same. However, the slave node BN sends the line data connected to the service channel connection unit 8 of its own node to the master node A via the transmission line C after adding and dropping the line data to the service channel.

FIG. 4 is a diagram showing a frame structure according to an embodiment of the present invention. In the figure, 1 multiframe is 2
It consists of 0 STM-1 frames F (1) to F (20), rows (1-9) of STM-1 frames and time slots (1-9) are SOH, and rows of STM-1 frames ( 1 to 9) and the time slots (11 to 270) are virtual C4s.

In the virtual C4, a predetermined time slot is used as a multi-frame synchronization pattern, an arbitrary number of time slots are used as a housekeeping channel, and the remaining time slots are used as service channels.

FIG. 5 is a block diagram showing a configuration of a master node according to another embodiment of the present invention, and FIG. 6 is a block diagram showing a configuration of a slave node according to another embodiment of the present invention. The system configuration of another embodiment of the present invention is shown in FIG.
Similar to the system configuration of the embodiment of the present invention shown in FIG. 2, it is assumed that the master node A and the slave nodes B1 to BN are connected in a loop via the transmission line C to form a loop network system.

When the STM-1 frame synchronization detector (hereinafter referred to as a frame synchronization detector) 21 of the master node A receives the reception data (RD) from the transmission path C, it extracts the reception clock (RC) from the reception data. Along with STM
-1 Frame synchronization is detected and received frame pulse (RF
P) is generated. The frame synchronization detection unit 21 receives the received data, the received clock, and the received frame pulse as SO.
It is sent to the H terminal unit 22.

The SOH terminating unit 22 is the frame synchronization detecting unit 2.
The SOH of the STM-1 frame, which is the received data, is terminated by the received data, the received clock, and the received frame pulse received from 1. At this time, the SOH terminating unit 2 receives the reception envelope signal (REV) indicating the position of VC4 by the AU pointer in the SOH of the STM-1 frame.
Of the received data excluding SOH, that is, STM-1
The VC4 of the frame, the reception clock, the reception frame pulse, and the reception envelope signal are input to the VC4 termination unit 23.
To send to.

The VC4 terminating unit 23 uses the reception data, the reception clock, the reception frame pulse and the reception envelope signal received from the SOH terminating unit 22 for the PO of the VC4.
Terminate H. When the VC4 terminator 23 terminates the POH of the VC4, the received data excluding the POH, that is, STM-1
The C4 of the frame, the reception clock, the reception frame pulse and the reception envelope signal are sent to the multi-frame synchronization detection unit 24.

When the multiframe synchronization detector 24 receives the reception data, the reception clock, the reception frame pulse and the reception envelope signal from the VC4 terminal 23, the multiframe synchronization detection unit 24 multiplies from the multiframe synchronization pattern stored in the predetermined time slot in C4. The frame synchronization is detected to generate a reception multi-frame pulse (RMFP). When the multi-frame synchronization detection unit 24 generates the reception multi-frame pulse, it sends the reception data, the reception clock, the reception frame pulse, the reception envelope signal, and the reception multi-frame pulse to the loop delay correction unit 27.

The clock generator 25 generates a master clock (MCK) of the loop network system according to another embodiment of the present invention, and the master clock is a frame pulse / multi-frame pulse generator (hereinafter referred to as a pulse generator) 26. To send to.

When the pulse generation unit 26 receives the master clock from the clock generation unit 25, the transmission clock (SC) from the master clock and the transmission frame pulse (SFP) indicating the frame synchronization pattern position of the STM-1 frame.
And a transmission envelope signal (SE
V) and a transmission multi-frame pulse (SMFP) indicating a multi-frame synchronization pattern position stored in a predetermined time slot in C4. The pulse generation unit 26 sends the transmission clock, the transmission frame pulse, the transmission envelope signal, and the transmission multi-frame pulse to the loop delay correction unit 27.

The loop delay correction unit 27 receives the reception data, the reception clock, the reception frame pulse, the reception envelope signal, the reception multiframe pulse from the multiframe synchronization detection unit 3, the transmission clock and the transmission frame pulse from the pulse generation unit 5, Loop delay correction for C4 is performed by the transmission envelope signal and the transmission multi-frame pulse. When the loop delay correction unit 27 performs the loop delay correction on C4, the transmission data (SD) after the delay correction is performed.
, The transmission clock, the transmission frame pulse, the transmission envelope signal, and the transmission multi-frame pulse are sent to the add / drop unit 28.

When the add / drop unit 28 receives the transmission data, the transmission clock, the transmission frame pulse, the transmission envelope signal, and the transmission multi-frame pulse from the loop delay correction unit 27, the service in C4 of the transmission data is received. Data from the line connected to the service channel connection unit 29 is dropped and added to the channel. The add / drop unit 28 also receives data from the line connected to the housekeeping channel connection unit 30 with respect to the housekeeping channel in C4 in the transmission data from the loop delay correction unit 27 (maintenance information, monitoring information, etc.). Branch and insert.

When the add / drop unit 28 adds / drops data to / from the service channel and the housekeeping channel in C4, the add / drop data, the transmit data with the data added / dropped to the service channel and the housekeeping channel, the transmit clock, and the transmit frame pulse are added. , And sends the transmission envelope signal and the transmission multi-frame pulse to the multi-frame synchronization pattern insertion unit 31.

Upon receiving the transmission data, the transmission clock, the transmission frame pulse, the transmission envelope signal, and the transmission multi-frame pulse from the add / drop unit 28, the multi-frame synchronization pattern insertion unit 31 receives the transmission multi-frame pulse as a basis. Then, the multiframe synchronization pattern is inserted into a predetermined time slot for the multiframe synchronization pattern in C4 of the transmission data. The multi-frame synchronization pattern insertion unit 31 sends the transmission data in which the multi-frame synchronization pattern is inserted in a predetermined time slot, the transmission clock, the transmission frame pulse, and the transmission envelope signal to the VC4 generation unit 32.

The VC4 generator 32 receives the transmission data from the multi-frame synchronization pattern inserter 31, the transmission clock,
The POH is added to the transmission data (C4) by the transmission frame pulse and the transmission envelope signal, and the transmission data with the POH added, the transmission clock, the transmission frame pulse, and the transmission envelope signal are added to the SOH adding unit 33.
To send to.

The SOH adding unit 33 uses the transmission data from the VC4 generating unit 32, the transmission clock, the transmission frame pulse, and the transmission envelope signal to transmit data (V
C4) is added with SOH, and the transmission data with the SOH added, the transmission clock, and the transmission frame pulse are STM-
The data is sent to the 1-frame synchronization pattern adding section (hereinafter referred to as the frame synchronization pattern adding section) 34.

The frame synchronization pattern addition unit 34 adds the frame synchronization pattern to the SOH of the transmission data by the transmission data from the SOH addition unit 33, the transmission clock, and the transmission frame pulse, and transmits the transmission data to which the frame synchronization pattern is added. It is sent to the slave node B1 via the transmission line C.

Therefore, by configuring the master node A as described above, one multiframe has 20 Ss.
A TM-1 frame, a predetermined time slot in C4 of this STM-1 frame is used as a multi-frame synchronization pattern, an arbitrary number of time slots in C4 is used as a housekeeping channel, and the remaining time in C4 is used. It is possible to generate a time division multiplexed frame in which a slot serves as a service channel. Further, the line data connected to the service channel connection unit 29 of its own node can be sent to the next slave node B1 via the transmission line C after being dropped into the service channel. Further, in the master node A, the delay between the received time division multiplexed frame and the time division multiplexed frame generated in the own node can be corrected by the loop delay correction unit 27.

When the frame synchronization detecting section 21 of the slave node B1 receives the reception data from the transmission path C, it extracts the reception clock from the reception data, and at the same time, STM-1
The frame synchronization is detected and the received frame pulse is generated. The frame synchronization detector 21 sends the received data, the received clock, and the received frame pulse to the SOH terminating unit 22.

The SOH termination unit 22 is the frame synchronization detection unit 2.
The SOH of the STM-1 frame, which is the received data, is terminated by the received data, the received clock, and the received frame pulse received from 1. At this time, the SOH terminating unit 2 generates a reception envelope signal indicating the position of VC4 by the AU pointer in the SOH of the STM-1 frame,
The reception data excluding SOH, that is, the VC4 of the STM-1 frame, the reception clock, the reception frame pulse, and the reception envelope signal are sent to the VC4 termination unit 23.

The VC4 terminating unit 23 receives the received data from the SOH terminating unit 22, the receiving clock, the receiving frame pulse, and the receiving envelope signal, and outputs the PO of the VC4.
Terminate H. When the VC4 terminator 23 terminates the POH of the VC4, the received data excluding the POH, that is, STM-1
The C4 of the frame, the reception clock, the reception frame pulse and the reception envelope signal are sent to the multi-frame synchronization detection unit 24.

When the multi-frame synchronization detector 24 receives the reception data, the reception clock, the reception frame pulse and the reception envelope signal from the VC4 terminating unit 23, the multi-frame synchronization detection unit 24 detects the multi-frame synchronization pattern stored in the predetermined time slot in C4. Detects frame synchronization and generates received multi-frame pulse. When the multi-frame synchronization detection unit 24 generates the reception multi-frame pulse, it sends the reception data, the reception clock, the reception frame pulse, the reception envelope signal, and the reception multi-frame pulse to the add / drop unit 28.

Upon receiving the reception data, the reception clock, the reception frame pulse, the reception envelope signal, and the reception multi-frame pulse from the multi-frame synchronization detection unit 24, the add / drop unit 28 receives the data in C4 of the reception data. Service channel connection unit 2 for service channels
The data from the line connected to 9 is dropped and added. Further, the add / drop unit 28 adds / drops data (maintenance information, monitoring information, etc.) from the line connected to the housekeeping channel connection unit 30 to the housekeeping channel in C4 in the received data.

When the add / drop unit 28 adds / drops data to / from the service channel and the housekeeping channel in C4, the received clock having the data added / dropped to the service channel and the housekeeping channel is used as the transmit data, and the receive clock is used as the transmit clock. As the transmission frame pulse, the reception frame pulse is transmitted, the reception envelope signal is transmitted as the transmission envelope signal, and the reception multi-frame pulse is transmitted as the transmission multi-frame pulse to the multi-frame synchronization pattern insertion unit 31, respectively.

Upon receiving the transmission data, the transmission clock, the transmission frame pulse, the transmission envelope signal, and the transmission multi-frame pulse from the add / drop unit 28, the multi-frame synchronization pattern insertion unit 31 receives the transmission multi-frame pulse as a basis. Then, the multiframe synchronization pattern is inserted into a predetermined time slot for the multiframe synchronization pattern in C4 of the transmission data. The multi-frame synchronization pattern insertion unit 31 sends the transmission data in which the multi-frame synchronization pattern is inserted in a predetermined time slot, the transmission clock, the transmission frame pulse, and the transmission envelope signal to the VC4 generation unit 32.

The VC4 generator 32 receives the transmission data from the multi-frame synchronization pattern inserter 31, the transmission clock, and
The POH is added to the transmission data (C4) by the transmission frame pulse and the transmission envelope signal, and the transmission data with the POH added, the transmission clock, the transmission frame pulse, and the transmission envelope signal are added to the SOH adding unit 33.
To send to.

The SOH adding unit 33 uses the transmission data from the VC4 generating unit 32, the transmission clock, the transmission frame pulse, and the transmission envelope signal to transmit data (V
SOH is added to C4), and the transmission data to which SOH is added, the transmission clock, and the transmission frame pulse are sent to the frame synchronization pattern addition unit 34.

The frame synchronization pattern addition section 34 adds the frame synchronization pattern to the SOH of the transmission data by the transmission data from the SOH addition section 33, the transmission clock and the transmission frame pulse, and the transmission data to which the frame synchronization pattern is added. It is sent to the slave node B2 via the transmission line C.

Therefore, by configuring the slave node B1 as described above, one multiframe has 20 STs.
It consists of M-1 frames, and C of this STM-1 frame
4 has a predetermined time slot as a multi-frame synchronization pattern, an arbitrary number of time slots in C4 as a housekeeping channel, and the remaining time slots in C4 as a service channel. Then, after the line data connected to the service channel connection unit 29 of its own node is dropped into the service channel, it can be sent to the next slave node B2 via the transmission line C. In addition, other slave nodes B2 ~
The BN has the same configuration as the slave node B1 described above, and its operation is also the same. However, slave node B
N drops the line data connected to the service channel connection unit 29 of its own node into the service channel, and then sends it to the master node A via the transmission line C.

FIG. 7 is a diagram showing a frame structure according to another embodiment of the present invention. In the figure, one multiframe consists of 20 STM-1 frames F (1) to F (20), and rows (1 to 9) and time slots (1 to 9) of the STM-1 frame are SOH.

VC4 whose head position is designated by an AU pointer (not shown) in SOH is composed of POH and C4. Within C4, a predetermined time slot is set as a multi-frame synchronization pattern, and an arbitrary number of time slots are set. Is a housekeeping channel and the remaining time slots are service channels.

As described above, the C4 is fixedly arranged at a predetermined position in the STM-1 frame forming the time division multiplex frame to form the virtual C4, and the frame synchronization pattern is inserted into the virtual C4. As a result, a time division multiplexing frame in which one multiframe is composed of 20 STM-1 frames can be realized, and the structure of one multiframe can be freely set. That is, STM-1
One multi-frame with the frame as the basic frame is 2.
In 5 msec, it is possible to realize a time division multiplexed frame suitable for accommodating a multimedia interface in which one frame is 125 μsec.

Further, ST forming a time division multiplex frame
By inserting the frame synchronization pattern into C4 of the M-1 frame, it is possible to realize a time division multiplex frame in which one multiframe is composed of 20 STM-1 frames, and the configuration of 1 multiframe is realized. It can be set freely. That is, one multi-frame with the STM-1 frame as the basic frame is 2.5 msec.
Thus, it is possible to realize a time division multiplexing frame suitable for accommodating a multimedia interface in which one frame is 125 μsec.

Although one embodiment of the present invention and the other embodiments have described the case where one multi-frame is composed of 20 STM-1 frames, one multi-frame is composed of one or more STM-1 frames. It is obvious that the method is applicable to cases and is not limited to this.

[0067]

As described above, according to the loop-type data transmission system of the present invention, C4 is fixedly arranged at a predetermined position in the STM-1 frame constituting the time division multiplex frame to form a virtual C4, By inserting the frame synchronization pattern in the virtual C4, there is an effect that the configuration of one multiframe can be freely set.

Further, according to another loop type data transmission system of the present invention, the STM which forms the time division multiplex frame.
By inserting the frame synchronization pattern in C4 of −1 frame, there is an effect that the configuration of one multiframe can be freely set.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a master node according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a slave node according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a system configuration of an embodiment of the present invention.

FIG. 4 is a diagram showing a frame structure according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a master node according to another embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a slave node according to another embodiment of the present invention.

FIG. 7 is a diagram showing a frame structure according to another embodiment of the present invention.

[Explanation of symbols]

 1,21 STM-1 frame synchronization detection unit 2,22 SOH termination unit 3,24 multi-frame synchronization detection unit 6,27 loop delay correction unit 7,28 add / drop unit 8,29 service channel connection unit 9,30 housekeeping channel Connection unit 10,31 Multi-frame synchronization pattern insertion unit 11,33 SOH addition unit 12,34 STM-1 frame synchronization pattern addition unit 23 VC4 termination unit 32 VC4 generation unit

Claims (2)

[Claims] 1. A master node and a plurality of slave nodes are connected in a loop via a transmission line, and one or more STM-s.
A loop-type data transmission system for performing data transmission between the master node and the plurality of slave nodes using a time division multiplexing frame composed of one frame, wherein a C4 including data information in the STM-1 frame is provided. Frame synchronization pattern inserting means for inserting a frame synchronization pattern for synchronizing the virtual C4 into the virtual C4 fixedly arranged at a predetermined position, and data between a line connected to the own node and the virtual C4. Data insertion means for sending and receiving
Transmission means for transmitting the time division multiplex frame including the virtual C4 in which the frame synchronization pattern is inserted and the data is exchanged on the transmission path, the time division multiplex frame transmitted on the transmission path, and the Loop correction means for correcting a delay with respect to the time division multiplexed frame received via the transmission line is provided in the master node, and is inserted into the virtual C4 of the time division multiplexed frame received via the transmission line. And data insertion means for transmitting and receiving data between the virtual C4 and a line connected to the own node in a subordinate synchronization with the frame synchronization pattern, and the virtual C4 of the time division multiplexed frame. Frame synchronization pattern inserting means for inserting the frame synchronization pattern into the virtual C4 to which the data has been exchanged by the data inserting means; A transmission means for transmitting the time division multiplexed frame including the virtual C4 into which the frame synchronization pattern has been inserted and the data has been transmitted and received on the transmission line, and each of the plurality of slave nodes are provided. Loop data transmission system. 2. A master node and a plurality of slave nodes are connected in a loop via a transmission line, and one or more STM-s.
A loop-type data transmission system for performing data transmission between the master node and a plurality of slave nodes by using a time division multiplexing frame consisting of one frame, in a C4 including data information in the STM-1 frame. The C4
Frame synchronization pattern insertion means for inserting a frame synchronization pattern for establishing synchronization, data insertion means for exchanging data between the line connected to the own node and the C4, and the frame synchronization pattern are inserted. And transmitting means for transmitting the time division multiplex frame including the C4 to / from which the data is transmitted / received on the transmission path, the time division multiplex frame transmitted on the transmission path, and the reception section via the transmission path. Loop correction means for correcting a delay with respect to the time division multiplex frame is provided in the master node, and subordinate synchronization is performed to the frame synchronization pattern inserted in the C4 of the time division multiplex frame received via the transmission path. And a data inserting means for exchanging data between the C4 and a line connected to the own node, and a data inserting means for inserting in the C4 of the time division multiplex frame. The frame synchronization pattern inserting means for inserting the frame synchronization pattern, which has been performed, into the C4 for which the data has been exchanged by the data inserting means, and the frame synchronization pattern has been inserted and the data has been exchanged. A loop-type data transmission system, wherein each of the plurality of slave nodes is provided with a transmission means for transmitting the time division multiplexed frame including C4 on the transmission path.