JPH01160131A - High efficiency signal transmission system between terminal equipment and exchange - Google Patents

Abstract

PURPOSE:To identify to which terminal equipment each call on a transmission line corresponds by adding an identifier corresponding to each terminal equipment to each cell multiplexed on the transmission line and sending the result. CONSTITUTION:Terminal equipments 18-0, 18-1,... output cells 22-0, 22-5,... or 22-1, 22-3,... to a transmission line 17. In such a case, identifiers 23-0, 23-5,... or 23-1, 23-3,... corresponding to the terminal equipments are added and outputted. Thus, when a signal processing means 20 receives each cell sent from the terminal equipments 18-0, 18-1,..., the original signals 21-0, 21-1,... are composed by separating the cell for each identifier, for example, with respect to the cell added with the identifier and storing the result to different buffers sequentially. Thus, even if a communication cell between the signal processing means 20 in the exchange 19 and the terminal equipments 18-0, 18-1,... in an optical cell period on the transmission line 17, they are separated and identified surely.

Description

[Detailed Description of the Invention] [Summary] Signals such as D channel signals are exchanged between a plurality of terminals and a signal processing means in an exchange that performs call processing, etc. by transmitting each D channel signal etc. over a transmission path. Regarding the high-efficiency signal transmission method between terminals and exchanges, such as D channel signals, in which ATM multiplexing and transmission is performed on a cell-by-cell basis during an arbitrary empty cell period, it is possible to identify which terminal each cell on the transmission path corresponds to. For the purpose of this, each cell multiplexed on the transmission path is transmitted with an identifier corresponding to each terminal indicating which of the terminals the cell is exchanged with. Configure.

[Industrial application field]

The present invention enables transmission and reception of signals such as D channel signals between a plurality of terminals and a signal processing means in an exchange that performs call processing, etc., at any empty cell period on a transmission path. This invention relates to a high-efficiency signal transmission system for terminals and exchanges, such as D channel signals, in which ATM multiplexing and transmission is performed on a cell-by-cell basis. .

[Conventional technology]

For example, a system as shown in FIG. 4 has been proposed as a signal transmission system in ISDN (Integrated Services Digital Network).

In this system, each subscriber vA1-0.

1-1. . . . each has a plurality of subscriber terminals 2-0-.
0.2-0-1. ..., and 2-1-0゜2-1
-1. ... are connected, and each subscriber line is connected to a B channel of B1-B+4 M channels (for example, M=2.23, etc.) for transmitting communication signals, and a call control signal (for example, an originating channel) as described later. 1-0.1-1.・
D channel separation section 3-0.3-1 corresponding to .
..., the D channel signal 5-0.5-1.・
, , are separated, the B channel signal -6-0,6-
1, . . . are further concentrated and multiplexed by the concentrator multiplexer 4,
The exchange is performed by inputting the input to the replacement switch 8 via the input highway 7, and the corresponding output highway 9-0.9-1,
Output to...

On the other hand, D channel separation section 3-0.3-1. . . D channel signals from each subscriber line 1-0.1-1 separated by 5-0.5-1. . . are the corresponding layer 1 processing units 11-0.11-1. in the D channel signal processing unit 10 installed in the exchange. . . , each buffer 12-0°12-1 . ... to the layer 2 processing unit 13, and further input to the call processing unit 14.

Here, layer 1 processing unit 11-0.11-1. ...
is an electrical interface, 31J] 1ii! The layer 2 processing unit performs frame decomposition,
The call processing unit 14 performs logical processing such as packet disassembly, and further performs call control based on the disassembled packet information, and converts the B channel signal 6-0.6-1. Wholesale of line control for...

In the above conventional example, subscriber line 1-0, for example, is time-divided into B channels and D channels, as shown in FIG. Here, the D channel signal 15 etc. output from the terminal 2-0-0 (FIG. 4) etc. is frame information as shown in FIG. 5, for example. Here, F indicates a flag field, which stores a bit string representing a frame break.

A indicates an address field and stores the source address and the like. C indicates a control field and stores control information. 3 indicates an information field, which stores packet data for call control (for example, calling packets), etc. Fe2 indicates a frame check sequence and stores a bit string for error control of each bit of the frame.

As shown in FIG. 5, the D channel signal 15 is time-division multiplexed into each D channel in five sections F0 to F of the subscriber line 1-0. Similarly, the D channel signal 16 from FJ* of subscriber line 1-0
The signal is time-division multiplexed into each D channel of 1 to FJI)K sections. Note that the data length of the packet data stored in one field of each frame of each D channel signal 15.16 may be different, so each frame length is variable, and therefore time division multiplexed to each D channel. The time interval lengths may also be different.

In the above operation, the D channel signal 15. from each terminal.
16 (Fig. 5), a controller (not shown in the figure) performs contention control to prevent collisions between one D channel on subscriber line 1-0, and transmits a D channel signal from one terminal. After that, the D channel signal of the other terminal is transmitted.

As described above, each D channel signal 5-0.5-1. is transmitted on each D channel of each subscriber line 1-0.1-1. . . is each D channel separation section 3-0.3-1. ..., only each D channel shown in FIG. 5 is extracted, and the D channel signal processing section 1
Each layer 1 processing unit 11-0.11-1.・・・
・Buffer 12-0.12-1. ...
is accumulated in At this time, as described above, a plurality of terminals 2-0-0.2-0-1 on one subscriber line, for example 1-0,
．． Since the D channel signals from ... are not mixed on each D channel, each buffer 12-0゜1
2-1. . . , the D channel signals 5-0.5-1 . ... inputs ().

Next, in the layer 2 processing unit 13, each frame (fifth
FCS after F field is detected (Figure 15, 16, etc.)
Error control is performed using each bit of the field, and the packet data within the field is extracted, and furthermore, the call control data within the packet data is extracted. Then, call control is performed in the call processing section 14 based on this data.

In the conventional example shown in FIG. 4, only the upstream transmission path (terminal-exchange) has been shown, but the downstream transmission path can also be implemented with completely opposite functions.

According to the conventional example mentioned above, each subscriber receives 16K (
'PD) bits/second or 1 tree with a D channel of about 64 bits/second and 2 B channels of about 64 bits/second
It is possible to realize ISD and NH3 that can be supplied with this degree of distortion. However, in the future, the demand for digital transmission in the 15DN network is expected to increase, and as shown in Figures 4 and 5.
Assign a channel to each time slot as shown in the diagram,
There may be limits to the method of synchronizing each channel across all networks and performing circuit switching.

Therefore, all networks in the 15DN network are synchronized. Instead, if you divide the transmission path into cell periods in units of data collections called cells of about 34 bytes and output data from each terminal onto the transmission path, if there is an empty cell period, ATM (As
synchronous Transfer Mode)
The high-efficiency signal transfer method of this method is attracting attention. In this method, a control area of several bytes (approximately 2 bytes) called a header is provided for each cell on the transmission path, and an exchange switch uses the control information attached to the cell header for each cell period. performs hardware switching and transfers to the target station or terminal. With this method, there is no need to completely synchronize each channel across the entire network, as is the case with circuit switching, and data can be transmitted in any available cell cycle.In addition, unlike with packet switching, the female switch A software operation is also required to perform the replacement while disassembling and assembling the cell.
Very high speed signal transfers, such as M (mega) bits/second, are possible.

[Problem that the invention seeks to solve]

In the ATM system, from the terminal on each subscriber line,
D for call control in frame format as shown in 5.16
When transmitting channel signals to an exchange, these frames are divided into several cells and arbitrarily multiplexed into empty cell periods on the transmission path. However, on the transmission path, cells multiplexed from other terminals are also mixed cell by cell, so the exchange cannot know from which terminal each cell has been transferred. The problem was that it could not be done.

Further, in contrast to the above, when cells are transmitted from an exchange to each terminal, exactly the same problem occurs.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide a high-efficiency signal transmission system for terminals and exchanges that can identify which terminal each cell on a transmission path corresponds to.

, [Means for solving the problems] FIG. 1 is a diagram explaining the principle of the present invention. A plurality of terminals 1B-0, 18-1, . A signal 21-0.21-1 corresponding to each terminal is transmitted between the signal processing means 20 in the
．． We will give and receive... These signals are, for example, call control signals such as outgoing packet data and incoming packet data. Each signal 21-0.21-1. ... is a signal 21-0-0°21 with the same data length on the transmission line 17.
-0-1. ...or 21-1-0. ．． 21-1-
1. ..., and any empty cell period To, T+, T3, Ts, ... on the transmission path 17 is divided into cells 22-0.22-1.22-3.22-5°... ATM multiplexed and transmitted. Also, other cell periods Tz
+T4+... etc., each terminal 18-0.18-
1. . . . and other terminals, etc., are sent to and received from cells 22-2, 22-4.・・・
・It is multiplexed as

At this time, the signal 21-0.21-1. Each cell 22-0.22-1.22-3.22-5.・・・
. . , each of those cells is terminal 18-0.18-1.
An identifier 23-0.23-1.23-3 corresponding to each terminal indicating which terminal is being exchanged with.
23-5. ... is added. This identifier is, for example, the end of the transmission line 17.

a subscriber line number identifying each subscriber line connected to the end;
Each terminal 18-0°18-1. connected to each subscriber line.
It consists of a terminal number for each subscriber line that identifies...

[For production]

By the above means, for example, each terminal 1B-0, 18-1, .
... is each cell 22-0.22-5. ...or 2
2-1.22-3. When outputting .・・・
・, or 23-1.23-3. ... is added and output, and the signal processing means 20 outputs each terminal 18-0.18-1 .
When receiving each cell transmitted from . If so, the original signal 21-0.21-1.
... can be assembled. Naturally, the operation is the opposite, that is, from the signal processing means 20 to each terminal 18-0.
18-1. It is possible to transmit cells to ... in the same way.

With the above operation, each terminal 18-0.18-1. ... and the signal processing means 20 in the exchange 19 are mixed, it is possible to reliably separate and identify them, and the AT
A highly efficient signal transfer method using the M method can be realized.

(Example〕 Hereinafter, embodiments of the present invention will be described in detail.

FIG. 2 is a configuration diagram of an embodiment of the present invention. This embodiment is based on signal transfer using the ATM method. In this system, each subscriber line 24-0.24-1.
. . . each has a plurality of subscriber terminals 25-0-0.2.
5-0-1. ..., and 25-1-0.25-1
-1. ... are connected, and each ATM multiplex signal 26-0.26-1 . . . is transmitted on each subscriber line.
... is a signal for inter-terminal communication from multiple terminals, and a call control signal (also from multiple terminals), as described later.
For example, D-channel signals for communication between terminals and exchanges, such as calling signals), are multiplexed asynchronously in arbitrary cell cycles on a cell-by-cell basis.

These ATM multiplexed signals 2670.26-1゜... are further concentrated multiplexed in the concentrator multiplexer 27, transmitted on the incoming highway 28 as a new ATM multiplexed signal 29, and input to the switch 30 for replacement. do.

In the ATM multiplex signal 29 exchanged at the switch 30, the signal for communication between terminals is sent to the corresponding output byway 3.
1-1.31-2. ... and transmitted to other stations, etc.

On the other hand, the p-channel signal for communication between the terminal and the exchange is output to the D-channel highway 32 and input as a D-channel multiplexed signal 33 to the cell separation unit 35 in the D-channel signal processing unit 34.

Each cell of the D channel multiplexed signal 33 inputted to the cell separation unit 35 is divided into terminals 25-0-0.25-0-1 .
..., and 25-1-0°25-1-1.・・・
・Layer 1 processing unit 36-0-0.36-0- corresponding to
1. ..., or 36-1-0.36-1-1.
... and buffer 37- in each processing section.
0-0.37-0-1,..., or 37-1-0.3
After being stored in 7-1-1゜..., the layer 2 processing unit 3
8 and further input to the call processing section 39.

Here, each layer 1 processing unit 36-0-”δ, .
As in the case of the conventional example shown in FIG. 4, logical processing such as frame disassembly and packet disassembly is performed, and the call control section 39 performs call control based on the disassembled packet information.

Next, the operation of this embodiment having the above configuration will be explained. First, subscriber line 24-0.24-1. ...Each A above
TM multiplex signal 26. -0.26-1. .

... is a transmission rate of, for example, 150 M C#) bits/second, and Co ~ Cb, `` ' and c,
As shown in ~C33,..., cells with a fixed data length are multiplexed every cell period, and each cell has a header section H.
, an information section 1nf, and a CRC code for error control, and has a data length of, for example, 34 bytes.

Here, each terminal 25-0-0.25-0-1°... and 25-1-0.25-1-1. The D channel signal outputted from ... is frame information as shown in 40 to 43 in Fig. 3(a) (different data lengths may be used), and this configuration is the same as that explained in Fig. 5. This is similar to , and the I field stores packet data for call control, etc. (calling packet, etc.).

For example, if the terminal 25-0-0 is connected to D shown in FIG. 3(a),
When channel signal 4o is multiplexed onto subscriber line 24-0, cell C0, which happens to have an empty cell cycle at that time,
c, and multiplexed into the information part 1nf. At this time, the terminal 25-0-0 adds a CRC code for error control, and also adds a CRC code to the header H of each cell c0°Cs, indicating that the cells are output from the terminal 25-0-0. Cell call number YCN=O is added and output.

Similarly, the terminal 25-0-1 divides and multiplexes the D channel signal 41 into information parts 1nf of cells Cz and Cb of the currently vacant cell period, and then sends these cells to the ladder part H to the terminal 25-0-1. The virtual call number VCN=1 is added to the virtual call number output from 0-1 and output.

On the other hand, it is exactly the same when the terminal 25-1-0.25-1-'1 multiplexes each D channel signal 42.43 onto the subscriber line 24-1, and each cell CI+C8 and C, , C
, t and multiplexed, and each header part H contains each vertical cell call number VCN=Q
+), and VCN=I C cell Cq.

C+z) is added and output.

Here, the Verch Cell Call Number VCN is L%24-0.24-1. for each subscriber. ...They are assigned in order from number 0 to each terminal above. Also, for example, other cells C+, Ca on each ATM multiplex signal 26-0.26-1
, Cs , ... and Cq + CIorCI31
... etc., signals for communication between terminals other than the D channel signal are multiplexed.

Next, the above ATM multiplex signal 26-0.26-1°...
is further concentrated and multiplexed in the line concentrator 27 of FIG. 2, and transmitted on the incoming highway 2S (FIG. 2) as an ATM multiplexed signal 29 shown in FIG. 3(a). The transmission rate at this time is, for example, 600 Mbit/sec.

Here, the concentrator multiplexer 27 receives each ATM multiplexed signal 26-0.
．． 26-1. An error check is performed using the CRC code of each cell, and a new CRC code is added only to valid cells, which are then multiplexed as an ATM multiplex signal 29.

Furthermore, for example, the cells Co, Ct, Cx, of the D channel signal related to the ATM multiplex signal 26-0,
Cb, ... to a new cell Cr a + Clq
＋Cz. , . . ., in addition to the vertical cell call number VCH, each header section H includes a line number LN=O indicating that these cells are transmitted from subscriber 4124-0 (Fig. 2). Add and output.

Similarly, for example, the cell C of the D channel signal related to the ATM multiplex signal 26-1, + Cs + C + l + CI
t*... as a new cell CI2. CI? ＋C! In
. . . When multiplexing is performed, in addition to the vertical cell call number VCN, each header section H contains a line number LN = 1 indicating that these cells have been transmitted from the subscriber line 24-1 (Fig. 2). is added and output.

The ATM multiplexed signal 29 multiplexed in the above manner is input to the switch 30 in FIG. 2, where it is sent to the cell C+ b * CIe + Cz + + .
Other channel data such as .
′・is output.

On the other hand, the cell Cra+ Cl5I C in FIG. 3(a)
I? D channel signals such as I Cl91Ct 11 + . It is transmitted as a signal 33 and input to the D channel signal processing section 34. At this time, the D channel multiplexed signal 33 is
), a new cell C2□*C! ? ＋・
... are stitched and multiplexed.

The D channel multiplexed signal 33 is input to the cell separation section 35 in the D channel signal processing section 3-4. Cell separation section 35
has a selector function consisting of hardware that detects the header part H of each input cell and separates each cell based on the line number LN added thereto and the vertical cell call number VCN. Each cell of the D channel multiplexed signal 33 is sequentially separated in the order of input, and each layer 1 processing unit 36-0-0.36-0-1.・
...and 36-1-0.36-1-1. ...and so on.

Each layer 1 processing unit performs an error check based on the CRC code added to each cell, and then inputs the contents of the information section rnf of each cell to each buffer 37-0 in the order of input.
-0.37-0-1. ...and 37-1-0.3
7-1-1. ..., etc. As a result, as shown in FIG. 3(b), each buffer stores frame information 40 to 43, which is the D channel signal originally output from each terminal.
is stored correctly.

With the above operation, the layer 2 processing unit 38 receives D from each terminal.
Channel signals can be correctly identified, and the call processing section 39 can perform appropriate call control.

In this embodiment, the D channel signal is also input to the exchange switch 30 in the same way as the negative channel data. That is, D
The channel signal is also treated as information destined for the D channel signal processing unit 34. As a result, the cotton collection multiplexing device 27 only needs to multiplex the effective cells on each subscriber line 24-0.24-1°... to the human highway 28, and as in the conventional example shown in FIG. Since a function such as a D channel separation section is not required, that section can be made into a single function.

Furthermore, the cell separation section 35 in the D channel signal processing section 34 can be realized by hardware, and can be implemented as a one-chip LSI by using today's large-scale integration technology. This makes it possible to save hardware resources compared to providing a D channel signal separation section for each subscriber line.

Note that the transfer of the D-channel signal from the D-channel signal processing section to each terminal can also be realized by completely reversing each function in the embodiment shown in FIG.

〔Effect of the invention〕

According to the present invention, it is possible to transfer signals between terminals and exchanges with high efficiency, such as D channel signals in the ATM system.

In addition, since the data can be mixed with other channel data and input directly to a replacement switch, it is possible to make a line concentrator and multiplexer into a single function, thereby reducing equipment costs.

Furthermore, since it is possible to separate cells such as D channel signals using hardware, it is possible to integrate especially the layer 1 portion of the signal processing means, saving hardware resources and lowering equipment costs. Can be done.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention; FIG. 2 is a configuration diagram of an embodiment of the present invention; FIG. Fig. 4 is a diagram showing a D channel signal processing system in a conventional line switching system, and Fig. 5 is an explanatory diagram of the D channel signal control 1 operation in the conventional example. 17... Transmission line; 18-0.18-1...terminal, 19...exchange, 20...signal processing means, 21-0.21-1...signal, 22-0 to 22-5...cell, 23-0. 23-1. 23-3. 23-5...
Identifier, T0-T, ... cell period.

Claims (1)

[Claims] 1) Each of a plurality of terminals (
18) and the signal processing means (20) in the exchange (19), each signal is transmitted through the transmission line (1).
In the terminal/switching facility high-efficiency signal transmission method in which ATM multiplexing and transmission is performed on a cell-by-cell basis in an arbitrary empty cell period in 7), each cell (22) multiplexed on the transmission path (17) has the following characteristics:
A terminal/switching facility high-efficiency signal characterized in that the cell is transmitted with an identifier (23) corresponding to each terminal indicating which of the terminals (18) the cell is exchanged with. Transmission method. 2) The identifier includes a subscriber line number that identifies each subscriber line connected to the end of the transmission line, and a terminal number for each subscriber line that identifies each terminal connected to the subscriber line. A terminal/switching facility high-efficiency signal transmission system according to claim 1, comprising: 3) When each of the terminals outputs each of the signals as each of the cells, the terminal adds the identifier corresponding to the terminal to each cell and outputs the signal, and the signal processing means outputs each of the signals via the transmission path. When inputting cells, each cell is separated into a buffer corresponding to each terminal based on the identification terminal attached to each cell.
3. The terminal/switching facility high-efficiency signal transmission system according to claim 1 or 2, characterized in that each of the signals accumulated and transmitted from each of the terminals is reproduced and identified.