JPS6047529A - Time-division multiplex communication system - Google Patents

Abstract

PURPOSE:To improve the use efficiency of a trunk circuit by sending the next data once the trunk circuit becomes free without waiting for a reception confirmation signal for the destination of the last transmit data. CONSTITUTION:When a request-to-send signal is generated by a terminal and stored in the storage circuit 12 of a transmitter 1, the decoding circuit 14 of a control circuit 13 decodes the contents of the request-to-send signal and supplies the result to a decision circuit 16. When it is decided that the trunk circuit corresponding to the destination of the request-to-send signal is free, the circuit 16 controls a control signal transmitting circuit 18 to send a transmission ready signal to the down control circuit 5 of the terminal, and opens the corresponding gate circuit 15 to control a selecting circuit 11, thereby connecting a main information circuit 5 from the terminal to the trunk circuit L3 corresponding to the destination. Then, a terminal receiving the transmissmion ready signal tranmits data without storing. In this case, the circuit 11 adds necessary information such as destination information and an error detection signal to the data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a time division multiplex communication system for selectively connecting digital data signal sequences arriving on a large number of information lines to a small number of relay lines. In particular, the present invention relates to a system for efficiently connecting data signal sequences generated in bursts to a high-speed data communication network.

[Background of the invention]

In an advanced information communication network, when transmitting information using still images, for example, information signals consisting of high-speed data signal sequences are generated in bursts. FIG. 1 is a model diagram showing the configuration of a communication network for transmitting and connecting data signal sequences generated in bursts. The terminals T1 and T2 are devices installed in the same house, and are connected to a terminal station BSU also installed in the house. This terminal equipment BSU is connected to the terminal equipment BSL on the central office side via the subscriber line L1.
Connected to T. The terminal device BSLT on the station side is connected to the multiplex communication device BMX via the line L2. Here, lines L1 and L2 shown as solid lines are main information lines for transmitting high-speed data signal sequences, and lines shown as broken lines are control lines for transmitting low-speed signals that control the main information lines. It is a line. Although these two types of lines may physically pass through the same cable, they are logically different lines with significantly different communication speeds.

In the multiplex communication device BMX, of these two types of lines, only the main information line is relay-connected to the trunk line L3 that transmits the high-speed data signal sequence. This trunk line L3 is not necessarily bidirectional, but may be unidirectional in the transmission direction in which information is frequently generated.

The trunk line L3 is configured as a mesh in FIG.

The control signals are transmitted via a separate switched network DNW.

Such a line configuration is considered to be an efficient configuration.

Here, the multiplex communication system to which the present invention is directed relates to communication between multiplex communication devices.

In order to make the explanation easier to understand, the explanation below will focus on one multiplex communication device BMX (S) that is a transmitter, another multiplex communication device BMX (R) that is a receiver, and communication control between them. .

[Description of prior art]

In such a conventional communication system, a transmitting device temporarily stores an input high-speed data signal string in a buffer memory, and depending on the storage capacity, it may also add data from other terminals to the flag pattern, address, etc. A method has been adopted in which an error detection signal and the like are added, these signals are arranged in time series to form one multiplexed frame, and the frame is sent to a relay line as a data signal sequence. Such transmission control uses a so-called high-level transmission procedure, in which the receiving device sends back the results of error checking on the received multiplexed frame to the transmitting device, and if there is an error, the same frame is retransmitted. method was adopted.

This method has the disadvantage that the transmitting device cannot transmit the next frame until it receives a response to one or several multiplexed frames that it has transmitted. Especially when the distance of the relay line is long and the propagation delay time is large, or the transmission speed of the relay line is high, the idle time that occurs on the relay line until a response is received will greatly reduce the usage efficiency of the relay line. There was a drawback.

In addition, this method of accumulating and processing input signals has the disadvantage that when the number of active terminals that have transmission data increases, a queue of transmission signals occurs in the buffer memory, increasing transmission delay. there were. Furthermore, since it is necessary to provide a buffer memory in the transmitting device to correspond to the terminal line, as the communication speed of the terminal line increases, the capacity of the buffer memory increases accordingly, resulting in an increase in the scale of the device. Ta.

[Purpose of the invention]

The present invention improves these drawbacks, and provides a time division multiplex communication system that increases the efficiency of using trunk lines, relieves transmission delays, and eliminates the need for large buffer memories in transmitting equipment. The purpose is to

Another object of the present invention is to provide a communication system that can efficiently accommodate different types of communication signals, such as a mixture of communication that requires error control and communication that does not require error control.

A further object of the present invention is to provide a flexible communication method that can efficiently distribute signals to a plurality of relay lines connected to a transmitting device and can communicate with any terminal.

[Features of the invention]

The present invention includes a transmitting device that transmits a time division multiplexed signal, and a receiving device that receives the time division multiplexed signal transmitted by the transmitting device, and the transmitting device is input with a data signal sequence generated in a burst. A large number of N main information lines, a control line through which signals for controlling the state of the main information lines are input/output, and a small number of M relay lines that transmit data signal sequences manually input to the main information lines are connected. The receiving device has a small number M' of relay lines and a large number N of relay lines that transmit data signal sequences to be input to the relay lines.
' main information lines and a control line through which signals for controlling the state of the main information lines are input/output are connected, and at least one of the relay lines is connected between the transmitting device and the receiving device. A main information line is connected between the transmitting apparatus and the receiving apparatus, and is connected to the main information line connected by the relay line. In a time division multiplex communication system configured such that the control line is connected via a communication network different from the relay line, the transmitting device has the N main information lines connected to the M relay lines. a selection circuit selectively connected to the line; a storage means for temporarily holding a transmission request signal input to the control line; and a control means for transmitting a transmission enable signal to the corresponding control line when the signal of the main information line can be transmitted to the trunk line, and the control means transmits the transmission request signal when receiving the transmission request signal. When the designated trunk line becomes vacant, the main information circuit is connected to the trunk line even if no reception confirmation signal is received from the receiving side for the previous data signal sequence, and
It is characterized in that it is configured to transmit a transmittable signal to a corresponding control line.

Furthermore, when the storage means contains a plurality of transmission request signals requesting connection to the same relay line for N main information lines, the control means controls the main information lines in accordance with a preset priority order. It is desirable to configure the 0 selection circuit to control the 0 selection circuit.

[Explanation based on examples]

FIG. 2 is a block diagram of an apparatus according to an embodiment of the present invention. The transmitting device 1, the receiving device 2, and the trunk line I73 of the multiplex communication device are connected to a set of the transmitting device BMX (S), the receiving device BMX (R), and the trunk line L3 in the communication network explained in FIG. Equivalent to.

The transmitting device 1 has a line L2 between it and a plurality of N terminal devices.
A main information line 3, an uplink control line 4, and a downlink control line 5 are connected via the main information line 3. The main information line 5 is connected to the input of one selection circuit 11.

The upstream control line 4 is input to a plurality of N memory circuits 12 each constituted by a shift register, and the readout output thereof is sent to a corresponding decoder circuit 14 of the control circuit 13, respectively. The outputs of the decoder circuits 1i814 are connected to control inputs of the selection circuit 11 via gate circuits 15, respectively. Further, the output of the decoder circuit 14 is branched and inputted to the determination circuit 16, and each gate circuit 15 is controlled by the output of the determination circuit 16.

A memory 17 is connected to the determination circuit 17 . Furthermore, the control signal transmission circuit 18 is controlled by the output of the determination circuit 16, and the configuration is such that a signal is transmitted to the downlink control line 5. The output side of the selection circuit 11 is connected to a relay line L3 going to each receiving device.

In the receiving device 2, the input signal of the relay line L3 is connected to the input of a selection circuit 23 via a branch circuit 21 and a delay circuit 22. The output of the selection circuit 23 is the main information line 3 of the line L2.
′. The signals branched by the branch circuit 21 are respectively input to the decoder circuit section of the control circuit 24, and the output of the decoder circuit 25 is connected to the control input of the selection circuit 23 via the gate circuit 26. The output of the decoder circuit 25 is branched and input to the judgment circuit 27.
The gate circuit section is controlled by the output of. Further, the control signal transmitting circuit 2B is controlled by the output of the determination circuit Fl&27, and a signal is transmitted from the control signal transmitting circuit 28 to the downstream control circuit 5'.

The memory circuit 12 is composed of a shift register of several tens of bits, the selection circuits 11 and 23 are composed of a matrix of logic gates, the delay circuit 22 is composed of a shift register, and the control circuits 13 and 24 are composed of a counter, a small-capacity It can be configured using existing integrated circuits such as memory.

The operation of the apparatus configured as described above will be explained using the operation time chart shown in FIG. Figure 3 (al and f
The time axis of bl is, for example, the time axis of the terminal T1 shown in FIG. 1, +al represents the main information line, and (b) represents the signal of the control line. The time axes of FIG. 3 (C1 and (dl) are, for example, the time axes of the multiplex communication device BMX (S) shown in FIG. 1, where (al represents the main information line and (bl represents the control line signal).

Assume now that a transmission request signal RQST#C is generated from the C-th terminal. This is the transmitting device 1 shown in FIG.
Once stored in the storage circuit 12 of the control circuit 13, the decoder circuit 14 of the control circuit 13 decodes the contents of this transmission request signal and provides it to the determination circuit 16. When the determination circuit 16 determines that the relay line corresponding to the destination of this transmission request signal is vacant, it controls the control signal transmission circuit 18 to send a transmission ready signal R.
DY#C is transmitted to the downlink control line 5 of the C-th terminal 3Z. Additionally, the corresponding gate circuit 15 is opened and the selection circuit 11 is controlled to connect the main information line 5 from the C-th terminal to the trunk line L3 corresponding to the destination based on the content of the transmission request signal RQST#C. . The C-th terminal that receives the ready-to-send signal RDY#C immediately transmits data DATA#C. Necessary information such as destination information and an error detection signal is added to this data by the selection circuit 1, and the data is immediately transmitted to the relay line L3 without being stored in a queue.

In the receiving device 2, the decoder circuit 25 of the control circuit 24 decodes the destination information at the head of the signal, and the determination circuit 27 controls the gate circuit 26 to give a control signal to the selection circuit 23, and selects the line L2 corresponding to the destination. Let them choose. Further, a control signal is transmitted from the control signal transmission circuit 28 to the downlink control line 5' of the corresponding line L2.

The data signal train on the line L3 passes through the separation circuit 21 and is sent to the delay circuit 22 for a short time required for the operation of the control circuit 24.
The signal is delayed and input to the selection circuit 23. At this time, the selection circuit 23 is connected to the destination line L2, and the data signal string is sent to the line L2 as it is.

As shown in FIG. 3, when a transmission request signal RQST#F is generated from the F-th terminal during transmission of this data signal string, when this transmission request signal is stored in the storage circuit 12,
The control circuit 13 identifies the destination, and when the destination can transmit using the currently vacant trunk line,
Sends a ready-to-send signal to the terminal. However, when this destination uses the trunk line L3 that is currently in use, the terminal is made to wait until the transmission of data DATA#C shown in Figure 3 is completed, and the trunk line is used. Immediately when a space becomes available, transmit ready signal RDY#
Send F to the Fth terminal. When the Fth terminal receives this, it transmits data DATA#F.

At this time, in the control characteristic of the system of the present invention, the next data DATA is transmitted as soon as the trunk line becomes vacant, without waiting until receiving the reception confirmation signal ACK#C from the destination for the previous transmission data DATA#C. # Send F. Therefore, the usage efficiency of the trunk line can be increased.

The received *acknowledgment signal ACK#C does not go through the transmitter 1,
It is directly transmitted to the Cth terminal. Upon receiving this, the terminal moves to the operation of transmitting the next data signal sequence if there is more data to be transmitted. Receipt disapproval signal 8C
If K#C is not received or if a reception non-confirmation signal NAK#C is received, the terminal is controlled to transmit the same data signal sequence again.

The length of the data signal string to be transmitted at one time is generally determined by the propagation delay time of the control response signal, the error rate of the relay line, the capacity of the data memory of the terminal, etc., and may be variable for each transmission request or It may be a fixed value or any value.

When the line L2 to be transmitted by the receiving device 2 is in use, the control signal transmitting circuit 28 transmits a busy signal to the transmitting terminal via the control line 5' to notify that the terminal line cannot be connected. Upon receiving this, the transmitting terminal stops transmitting the data signal sequence and retransmits the data according to a predetermined procedure.

0 The control circuit 13 is configured to control the connection to the relay line according to a preset priority order when transmission request signals are stored in the plurality of storage circuits 12. This priority order is initially set, for example, by the user subscribing to a desired rank from among several service ranks prepared by the service provider.

In this way, the trunk line is shared by a large number of terminals in a time-division manner.

〔Effect of the invention〕

As explained above, according to the present invention, signals transmitted from different terminals are not multiplexed within the same signal frame, and sequential lines are allocated to individual data signal sequences. There is no need to wait for the response of
The efficiency of using trunk lines can be improved. Since the response signal is transmitted and received for each terminal, even if retransmission signals due to error control or the like are mixed, there is no need to distinguish between them in communication control, so the apparatus can be simplified. moreover,
Since the main information is not stored in the transmitting device, there is an advantage that the delay in the 7 6 transmission path is small and the device configuration of the transmitting device can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a model configuration diagram of a line network to which the present invention is applied. FIG. 2 is a block diagram of the transmitting device and receiving device of the device according to the embodiment of the present invention. FIG. 3 is a time chart for explaining the operation of the apparatus according to the embodiment of the present invention. 8

Claims (2)

[Claims] (1) A transmitting device that transmits a time division multiplexed signal and a receiving device that receives the time division multiplexed signal transmitted by the transmitting device, and the transmitting device receives a data signal sequence generated in a burst shape. A large number of 8 main information lines, a control line through which signals controlling the state of the main information lines are input/output, and a small number of M relay lines that transmit data signal sequences input to the main information lines are connected. , The receiving device has a small number of N' relay lines and a large number of N' relay lines that transmit data signal sequences input to the relay lines.
' main information lines and a control line through which signals for controlling the state of the main information lines are input/output are connected, and at least one of the relay lines is connected between the transmitting device and the receiving device. The device is connected to be able to transmit the data signal sequence in the direction of the receiving device, and further, between the transmitting device and the receiving device is a main information line connected by the relay line. In a time division multiplex communication system configured such that the control line is connected via a communication network different from the relay line, the transmitting device has the N main information lines connected to the M relay lines. a selection circuit selectively connected to the line; a storage means for temporarily holding a transmission request signal input to the control line; and a control means for transmitting a transmission enable signal to the corresponding control line when the signal of the main information line can be transmitted to the trunk line, and the control means transmits the transmission request signal when receiving the transmission request signal. When the designated trunk line becomes vacant, the main information circuit is connected to the trunk line even if no reception confirmation signal is received from the receiving side for the previous data signal sequence, and
A time division multiplex communication system characterized by being configured to transmit a transmittable signal to a corresponding control line. (2) When the storage means contains a plurality of transmission request signals requesting connection to the same relay line for N main information lines, the control means selects the main information lines in accordance with a predetermined priority order. 12. The time division multiplex communication system according to claim 11, wherein the selection circuit is configured to control the selection circuit to select.