JPH104415A - Data transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data transmitter in which a delay in the case of data transmission is reduced when a data exchange means acts like a relay station. SOLUTION: This data transmitter is made up of a private branch of exchange(PBX) 4 acting like a relay station, a transcoder 3 applying band compression to reception data from the PBX 4, a transcoder 2 sending a signal whose band compression is released to the PBX 4, a CLAD section 15 assembling received data from the transcoder 3 into cells, and an ATM multiplexer 1 having a CLAD section 14 disassembling the received data from other data transmitter and sending the result to the transcoder 2. When the PBX 4 acts like a relay station, the transcoder 3 sends the received data from the PBX 4 to the CLAD section 15 without band compression and the transcoder 2 conducts a data path-through operation to send the data from the CLAD section 14 to the PBX 4 without releasing the band compression.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device, and more particularly to an improvement in a processing procedure in a data transmission device used in a data transmission system including a plurality of nodes.

[0002]

2. Description of the Related Art As an example of a data transmission apparatus, an ATM multiplexing apparatus used in an ATM data transmission system for handling voice data will be described with reference to FIG. In FIG. 1, an ATM multiplexer 1 has an interface (I
F) 11, 12 and ATM switch 13 (ATM S
W) and CLAD for converting data into cells / cells
It is composed of parts 14, 15 and the like. The ATM multiplexer 1 is connected to a private branch exchange (PBX) 4 via transcoders (TRC; band compression codecs) 2 and 3.

Although not shown, similar ATM multiplexers (adjacent ATM multiplexers) are connected to the interfaces 11 and 12 of the ATM multiplexer 1 shown in FIG. ATM between multiple nodes
A data transmission system has been constructed. These adjacent ATM multiplexers have the same configuration as described above, and are similarly connected with a transcoder and a PBX.

In this ATM data transmission system, PB
The voice data from X4 is band-compressed by the transcoder 3 and is converted into a cell (cell assembly) in the CLAD unit 15 of the ATM multiplexer 1. The ATM switch 13 connects the adjacent ATM multiplexers via the interfaces 11 and 12. Sent to

Further, data (AT) input from an adjacent ATM multiplexer via interfaces 11 and 12 is used.
M cell) via the ATM switch 13 to the CLAD unit 14
, Is decellularized (reassembled) in the CLAD unit 14, is decompressed by the transcoder 2, and is input to the PBX 4. In this way, data transmission using ATM cells is performed between adjacent PBXs or between ATM multiplexers.

In this data transmission system, in order to increase the transmission efficiency of audio data, the above-described band compression of the audio data is performed by the transcoder 3, and thereafter, the ATM multiplexer 1 performs cell assembly / reassembly. Is performed, and data transmission by ATM cells is performed. Generally, such cell assembly / reassembly is performed for each audio channel. In addition, voice data is band-compressed to, for example, 16 kbps, and therefore, the cell assembly processing time in the ATM multiplexer 1 generally takes about 20 ms.
Note that the CLAD units 14 and 15 accommodate a PBX line for each audio channel.

[0007]

By the way, for example, in the above-mentioned ATM data transmission system, a PBX having a relay switching function, that is, a PBX that can function as a relay station may be used. In this ATM data transmission system, when the PBX becomes a relay station, the transcoder 3 is used to prevent voice quality deterioration.
Does not perform audio band compression processing, that is, performs a data pass-through operation.

On the other hand, a CLAD unit 14 which is a cell assembly / reassembly unit in the ATM multiplexer 1
15 operates regardless of the state of the PBX, that is, the PBX
Performs the operation of the cell assembly / reassembly even when operates as a relay station. Therefore, even in this case, the processing time of the cell assembly / reassembly in the ATM multiplexer does not change.

As described above, even when the PBX is performing the relay exchange, the cell assembly / ATM assembly by the ATM multiplexer is performed.
Since the reassembly process is performed, the number of nodes x
(Processing time in the ATM multiplexing device). In addition, since such a delay increases with an increase in the number of relay stations, there is a problem that the number of relay stations is limited.

[0010] It is an object of the present invention to provide a data transmission apparatus capable of reducing a delay in data transmission when a data exchange means such as a PBX functions as a relay station.

[0011]

According to the present invention, there is provided a data transmission apparatus, comprising: a data exchange unit capable of functioning as a relay station; formatting data received from the data exchange unit; and deformatting the data. A format / deformatting means for transmitting to the data exchange means, and cellizing the data received from the format / deformatting means and transmitting the data to another data transmission device, and decelerating the reception data from the other data transmission device. Celling / decellulating means for transmitting to the format / deformatting means, and when the data exchange means functions as a relay station,
The deformatting means transmits the data received from the data exchange means to the celling / decellifying means without performing a format process, and the data from the cellifying / decelerating means without performing a deformatting process. It is characterized by performing a data pass-through operation for transmitting to the exchange means.

In an actual data transmission device,
When the data exchange means functions as a relay station,
The decelerating unit transmits the data received from the format / deformatter to another data transmission device without cellifying the data, and performs the format / deformatting without receiving data from another data transmission device. Perform a data pass-through operation for transmission to the means.

In a preferred embodiment, the format
The data pass-through operation in the deformatting means or the celling / decellulating means is controlled by the data exchange means. Also, preferably, the cells in celling and decellularization are ATM (asynchronous transfer mode) cells. The format / deformatter is, for example, a band compressor / decompressor, and the data is audio data.

[0014]

Embodiments of the present invention will be described below. In the following description, an embodiment in which the data transmission apparatus of the present invention is applied to an ATM multiplex system that performs ATM multiplex transmission of voice cells and other data cells will be described. It goes without saying that the present invention can be similarly applied.

FIG. 1 shows a data transmission apparatus according to an embodiment of the present invention. Since the components of the data transmission device are substantially the same as those described above, detailed description of each component will be omitted, and only different points will be described below.

That is, the data transmission apparatus of this embodiment is different in that the data pass-through operation in the transcoders 2 and 3 is performed by the PBX 4.
Then, in a relay exchange state in which the PBX 4 operates as a relay station, the transcoders 2, 3 and the CLAD unit 14,
15 performs a data pass-through operation in accordance with the sequences shown in FIGS. 2 (a) and 2 (b), respectively.

In FIG. 2A, first, the transcoders 2 and 3 determine whether or not data pass-through is detected based on a control signal from the PBX 4 (S1). When detecting the data pass-through, the transcoders 2 and 3 perform the data pass-through operation,
4 and 15 are notified of data pass-through detection. If data pass-through is not detected in step S1, the transcoders 2 and 3 perform normal operations, that is, perform data band compression and decompression, and notify the CLAD units 14 and 15 that data pass-through has not been detected (S1).
3).

On the other hand, the CLAD units 14 and 15
As shown in (b), it is determined whether there is a notification of data path through detection from the transcoders 2 and 3 (S4). When the data pass-through is detected, the CLAD unit 1
4 and 15 perform a data pass-through operation (S5). If there is no notification of data pass-through, the CLAD units 14 and 15
Performs a normal operation (S6).

FIG. 3 shows an example of the data format of the outputs S1 to S4 during normal operation in the data transmission apparatus according to the embodiment, that is, when the data through path operation is not performed. FIG. 4 shows an example of outputs S1 to S4 during a data pass-through operation in the data transmission apparatus according to the embodiment. FIG. 5 shows an output S1 at the time of data pass-through in the prior art.
6 to S4.

In these figures, a header portion added to an ATM cell is omitted for convenience. In the illustrated example, the ATM cell includes a 16-kLD-CELP band compression signal in a payload of the ATM cell of 48 bytes.
It shall be stored.

The above operations will be described below. First, a case of a normal operation, that is, a case where the PBX 4 does not operate as a relay station (not a relay switching operation) will be described. In this case, the audio CLAD unit 14 on the reception side transmits to the transcoder 2 a 16 kL reassembled reception cell.
The D-CELP band compression signal is transmitted every 16 kbps (S1 in FIG. 3). Next, the transcoder 2 decodes the received data and converts it into a 64 kPCM signal (S
2) and send it to PBX4.

In addition, the PBX 4 has 6
The 4 kPCM signal (S3 in FIG. 3) is sent to the transcoder 3. The transcoder 3 performs audio band compression processing,
The 16kLD-CELP signal (S4 in FIG. 3) is converted to audio CLA
It is sent to the D section 15. The audio CLAD unit 15 accumulates the received signals, sequentially performs cell assembly, and transmits cells.

Next, a data pass-through control operation in the data transmission apparatus according to the embodiment will be described. Note that this operation is performed when the PBX 4 is a relay exchange.

First, the transcoders 2, 3 and the audio CLAD units 14, 15 perform a data pass-through operation in accordance with the sequence of FIG. In the receiving direction, when the data pass-through operation is performed, the voice CLAD unit 2 reassembles the data of the received cell and transmits a 16-kLD-CELP band compression signal in 8-bit (64-kbps) units (S1 in FIG. 4).

The transcoders 2, 3 and PB
X4 indicates data through for both transmission and reception (S10 in FIG. 4)
In S4), the data is sent to the audio CLAD unit 15 on the transmission side. At this time, the transmission data (S1 in FIG. 4) from the audio CLAD unit 14 is reassembled for each cell,
A fixed pattern is inserted between cells so that the cell generation interval is the same as in the normal case. The audio CLAD unit 15 on the transmission side receives the received data (S in FIG. 4).
1) is assembled for each cell, and the cell is reproduced.
For this reason, the audio CLAD unit 15 has a function of detecting a fixed pattern between cells and detecting a data area of one cell.

With the above operation, the cell generation time or assembly is reduced to about one-fourth of the normal time, and the processing time at the relay node is reduced. That is, according to the present invention, when a data signal such as a voice signal is transmitted between the PBX 4 and the transcoders 2 and 3 and the ATM multiplexer 1, and is converted into cells / decells for each channel, the PBX 4 and the relay stations PBX4 and In addition to the transcoders 2 and 3, data pass-through processing is performed in the audio CLAD unit 14 for decellularization and the audio CLAD unit 15 for cellularization. That is, 64 from the decellularized voice CLAD unit 14
Voice CLAD for cell conversion of kbps cells
It is transmitted to the unit 15, whereby the delay time is reduced.

Next, a data pass-through operation according to the prior art will be described. This data pass-through operation is performed by the PBX4
Is an operation performed when a relay exchange is performed. In addition,
In this case, the operation of the audio CLAD units 14 and 15 is the same in both transmission and reception as in normal operation.

In this case, after detecting the data pass-through, the transcoder 2 performs through control on the received data (S1 in FIG. 5) and sends it out to the PBX 4 (S2 in FIG. 5).
Then, since the PBX 4 performs the relay exchange, the PBX 4
4 (S2 in FIG. 5) becomes the transmission data from the PBX 4 (S3 in FIG. 5).

Further, the transcoder 3 controls through the received data from the PBX 4 and sends out data (S4 in FIG. 5) to the audio CLAD unit 15. Here, since the data format between the transcoder 3 and the audio CLAD unit 15 does not change, the processing time in the audio CLAD unit does not change from the normal time.

In comparison with the prior art, the present invention relates to a method in which data pass-through in a transcoder and cellization and decellulation in an ATM multiplexing device are linked to each other.
The effective transmission rate of data in the relay section of the BX can be increased, and the delay at the relay node is reduced.

[0031]

According to the present invention, it is possible to reduce the delay in data transmission when the data exchange means functions as a relay station (node), that is, to reduce the processing time at the node. Can be provided. Therefore, the present invention is particularly effective in the case of multi-node relay.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of a data transmission device of the present invention.

FIG. 2 is a flowchart illustrating an operation sequence of data pass-through in the data transmission device of FIG. 1;
(A) shows the procedure on the transcoder side, and (b) shows the procedure on the CLAD section side.

FIG. 3 is an explanatory diagram of an operation of the data transmission device of FIG. 1;

FIG. 4 is an explanatory diagram of an operation of the data transmission device of FIG. 1;

FIG. 5 is an explanatory diagram of an operation of a conventional data transmission device.

[Explanation of symbols]

 1 ATM multiplexer 2, 3 transcoder 4 PBX 14, 15 CLAD unit

Claims (7)

[Claims] 1. A data exchange means operable as a relay station, and a format / deformat means for formatting received data from the data exchange means, deformatting the data and transmitting the data to the data exchange means. Cellizing the received data from the format / deformatting means and transmitting the data to another data transmission device, and decellulating the received data from the other data transmission device and transmitting the data to the format / deformatting means. When the data exchange means functions as a relay station, the format / deformatter means performs the cell / deceleration without formatting the data received from the data exchange means. Means, and
A data transmission apparatus for performing a data pass-through operation of transmitting data from a decelerating unit to the data exchanging unit without performing a deformatting process. 2. The data transmission apparatus according to claim 1, wherein a data pass-through operation in said format / deformatting means is controlled by said data exchange means. 3. When the data exchange means functions as a relay station, the celling / decellulating means transmits data received from the format / deformatting means to another data transmission device without cellifying. 3. The data transmission device according to claim 1, further comprising performing a data pass-through operation of transmitting data received from another data transmission device to the format / deformatter without decelerating the data. 4. The data transmission apparatus according to claim 3, wherein a data pass-through operation in said format / deformatting means and said celling / decellulating means is controlled by said data exchange means. 5. The data transmission device according to claim 1, wherein the cells in the celling and the decelling are ATM (Asynchronous Transfer Mode) cells. 6. The data transmission apparatus according to claim 1, wherein said format / deformatting means is a band compression / decompression means. 7. The data transmission device according to claim 1, wherein the data is audio data.