JPH0728313B2 - Full-duplex transmission control method - Google Patents

Description

The present invention relates to a transmission control system in a full-duplex transmission system,
In particular, it relates to a transmission control method for controlling a frame format.

(Prior Art) Communication in which a main device and a terminal are connected by a full-duplex transmission line, a circuit-switched channel C and a packet channel P are multiplexed in such transmission, and allocation of transmission bands of both can be controlled. The system and voice / data integrated LAN are being studied. In order to allocate while changing the transmission bands of the channels P and C dynamically, for example, a signaling channel is used to determine the bandwidth to be allocated between the main device and the terminal, and to update / change the band allocation. It is necessary to control the time at the transmitting side and the receiving side at the same time. However, it is difficult to match the time at which the bandwidth is changed on the transmission side and the reception side only by software-driven processing using the signaling channel. Therefore, a method is being considered in which a transmission control field is provided in a time division frame and the transmission side and the reception side simultaneously update the band allocation based on the band allocation information indicated by the control field.
A conventional procedure for transmission control in such a communication system will be described. In FIG. 1, a terminal 10 is connected to a switching network 2 via a terminal interface circuit 3. The central control circuit 1 controls the connection of the switching network 2 and also controls the connection of each terminal via the channel D. A transmission frame of the full-duplex subscriber lines 11 and 12 is shown in FIG. This transmission frame includes a synchronization signal SYN, a channel D for signaling communication, a circuit switching channel C, a packet channel P, and a transmission control field AC indicating a boundary position between the P channel and the C channel. When there is a communication request for C channel communication in the band c1 from the terminal 10 via the channel D, the central control circuit 1 controls the line connection and
Allocation permission of the band c1 is transmitted to the terminal 10 through the channel D, and the terminal interface circuit 3 is also allocated the band c1 through the control communication path (not shown). Based on the allocation control information, the terminal 10 and the terminal interface circuit 3 write information BND indicating the boundary position between the channels C and P of the respective outgoing transmission lines in the transmission control field AC.

(Problems to be Solved by the Invention) In this conventional example, it is necessary for the central control circuit 1 and the terminal interface circuit 3 to send and receive the boundary information BND on the transmission line 11, which makes the terminal interface circuit large-scale and the central control. This leads to increased processing in the circuit.

It is to realize a full-duplex transmission control system that does not require transmission and reception of control signals between the central control circuit and the terminal interface circuit.

(Structure of the Invention) A full-duplex transmission control method of the present invention is a full-duplex transmission system in which a main device and a slave device communicate with each other using a time division frame having a circuit-switched channel and a packet channel. The transmission control field for transferring the band allocation information of the channel and the packet channel is provided in the time division frame, and the band allocation information in the transmission path from the master device to the slave device is set in the transmission path from the slave device to the master device. Transferred using the transmission control field of the divided frame, and the band allocation information in the transmission control field is band allocation information for transmission from the slave device to the master device or a band allocation for transmission from the master device to the slave device. It is characterized in that an identification bit indicating whether or not it is information is defined in the transmission control field.

(Example) An example of the present invention will be described with reference to FIGS. 2 and 3.
When the boundary between channels C and P is changed, the central control circuit 1 uses the channel D to control the terminal control circuit 100 of the terminal 10.
Is notified of the boundary position or the band of channel C. This signal path is formed by the multiplexing circuit 401, the transmission path 12, and the separation circuit 301. The terminal control circuit 100 sets the changed data in the register 103 in order to change the boundary of the transmission path 11, and at the same time supplies the changed data to the AC field input of the multiplexing circuit 101. FIG. 2 (b) shows the details of the AC field. This field is composed of boundary information BND and an identification bit M indicating whether it is boundary information of the transmission line 11 or control information of the transmission line 12. When the number of time slots of the changed channel C is 12, BND = 1100 (binary display) and M = 0 indicating the control information of the transmission path 11 are given as an AC field. The control circuit 102 controls the multiplexing circuit 102 based on the value of the register 103. Therefore, the multiplex control is performed according to the changed frame structure. In the separation circuit 201 of the terminal interface 3, the value of the AC field is stored in the register 204, and the bit M is supplied to the selection control terminal of the selector 205. Since M = 0, the data in the register 204 is supplied to the register 203. The control circuit 202 separates the channels P and C in this frame based on this value. That is, separation control is performed based on the changed band allocation.

Next, band control of the transmission line 12 will be described. The terminal control circuit 100 inputs BND = 110 to the AC field input of the multiplexing circuit 101.
Supply an AC field consisting of 0 and M = 1. In this case, since the register 103 is not changed, the multiplexing control of the multiplexing circuit 101 does not change. This AC field information is registered
Supplied to 204. In this case, since M = 1, this data is supplied to the register 403 via the selector 205. The data in the register 403 is supplied to the AC field input of the multiplexing circuit 401, and at the same time, the control circuit 402 performs multiplexing control of the channels P and C based on the changed data. Separation circuit 301 supplies the AC field value to register 303. The control circuit 302 determines the separation circuit 301 based on the changed data.
Control is performed.

In this description, the symmetric communication in which the channels C of both transmission lines have the same band is taken as an example, but the present invention can also be applied to asymmetric communication in which the transmission lines differ. Also, although the configuration is shown in which the channel D is used for signaling communication between the terminal and the central control circuit, it is also possible to use the channel P or C.

Further, in the present embodiment, the transmission line 11 and
Although the bandwidth allocation with 12 is set independently,
The boundary information of 12 may be shared, and the boundary information of the transmission path 11 may be directly returned to the transmission path 12 at the terminal interface 3. That is, without identification by M bits,
The configuration is such that it is supplied to the registers 203 and 403 and the multiplexing circuit 401 without going through the terminal interface circuit 3 selector 205.

(Effect of the invention) The terminal side controls the boundary between the circuit switching area and the packet switching area of the transmission frame between the terminal and the terminal interface circuit.
Boundary control can be performed not only for the transmission path from the terminal to the terminal interface circuit but also for the transmission path from the terminal interface circuit to the terminal. Therefore, it is not necessary to exchange control information relating to boundary control between the terminal interface and the central control circuit, and the terminal interface circuit does not need a device for exchanging control information. Can be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an example of a communication system using the present invention,
FIG. 2 is a diagram showing a transmission frame, and FIG. 3 is a diagram showing an embodiment of the present invention. In the figure, 1 is a central control circuit, 2 is a switching network, 3 is a terminal interface, 10 is a terminal, 11 and 12 are transmission lines, 100 is a terminal control circuit, 101 and 401 are multiplexing circuits, 201 and 301 are demultiplexing circuits. , 102, 202, 302, 402 are control circuits, 103, 203, 303, 4
03 and 204 are registers, and 205 is a selector.

Claims (1)

[Claims] 1. A full-duplex transmission system in which a main device and a slave device communicate with each other using a time division frame having a circuit switching channel and a packet channel, and transfers band allocation information of the circuit switching channel and the packet channel. A transmission control field for setting the time division frame is provided in the time division frame, and the band allocation information in the transmission path from the master device to the slave device is transferred using the transmission control field of the time division frame in the transmission path from the slave device to the master device. Transmitting the identification bit indicating whether the band allocation information in the transmission control field is band allocation information for transmission from the slave device to the master device or band allocation information for transmission from the master device to the slave device Full-duplex transmission control method characterized by being defined in the control field.