JPH1065676A - Conversion method for voice information cell and assembling and disassembling device for the cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively transmit both voice and data information with use of a single cell by packing a data packet into a free space of the cell that is produced, based on the cell assembling limit time. SOLUTION: The cell assembling limit time elapses when the compressed voice information are turned into the voice packets #1 to # and these packets are put into a cell. If no voice packet is generated in such cases, the data equivalent to the idle capacity of the cell are read out of a data information memory 16 and packed into the cell as a data packet. The data information is previously divided into the packets in the fixed length and packed into an idle part. If the idle capacity is smaller than the quantity of fixed length data, the data information Ds overflowed the cell is packed into the cell to be assembled next as a data packet. Thus, both voice and data information cells are filled with each relevant information and can be sent within the cell assembling limit time. Then the voice communication is possible with high efficiency and with no deterioration of the voice quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell conversion method for packetizing voice information and packing the packet into cells, and more particularly to a method for increasing transfer efficiency, a cell assembling apparatus, and a cell disassembling apparatus.

[0002]

2. Description of the Related Art ATM (Asynchronous Transfer Mode) is characterized in that all information such as images, texts and voices can be processed by the same physical line regardless of the nature of transfer data such as the type of transfer speed. However, it is currently mainly used for transmitting data information. Generally speaking,
In particular, in private networks or dedicated lines for special purposes such as between a base station and a converter in mobile communications, the low bit rate of voice information is used to efficiently utilize limited network capacity and reduce line costs. Rate compression and silence compression are essential. In recent low-bit-rate audio coding systems of 8 kb / s or less, compressed audio information is generated in bursts in units of tens to hundreds of bits for every 10 ms to 50 ms frame. It is conceivable that the compressed voice information for each frame is packed in an ATM standard cell as a voice packet and transmitted as an ATM cell. In this case, it is conceivable that compressed audio information of a plurality of channels is multiplexed and packed in a cell in order to prevent the audio delay from deteriorating the quality and increase the ATM transfer efficiency.

For example, as shown in FIG. 5, a header h is added to each of the three bursts of compressed audio information ch-1 to ch-3 in order from the earliest generated burst, and the packet is sequentially packed in the ATM cell payload as an audio packet. Silence is compressed without silence in the cell. This makes it possible to transmit audio information with high efficiency.

[0004]

When the number of voice channels is small or when there are many silent parts, it takes a long time to pack all voice packets into one cell, and the delay may cause a decrease in voice communication quality. Become. In order to suppress this delay, as shown in FIG. 6, a cell assembling time limit Ts is provided from the time when the compressed voice # 1 that first fills the cell is generated.
If the filling of the voice packet into one cell is not completed within the time limit Ts, it is necessary to perform a padding process of inserting dummy data into the empty portion. The padding process causes a problem that transmission efficiency is reduced.

[0005]

According to the cell conversion method of the present invention, a data packet obtained by packetizing data information is packed together with a voice packet. This data packet fills the cell vacancy generated based on the cell assembly time limit.
A fixed-length data packet is prepared in advance, and the data information that appears by filling the data packet in the space is packed as a data packet in a cell to be assembled next. According to the cell assembling apparatus of the present invention, the voice information is input by the first payload generation means, the data information is input to the second payload generation means, and the data information is replaced by the switching means by the first payload generation means. The payload generated by any of the first and second payload generation means is selected by the selection means, and the selected payload and the cell header generated by the cell header generation means are added.

According to the cell disassembly device of the present invention, the payload input to the separation means is separated into information for each packet, the payload input to the data processing means is output as data information, and the header of the received cell is The data is analyzed by the header analyzing means, and the payload of the cell is supplied to the separating means or the data processing means. The voice information and the data information separated by the separating means are separated and outputted by the separating means.

[0007]

FIG. 1 shows an embodiment of a cell assembling apparatus according to the present invention. For example, audio information in which compressed audio of a plurality of channels is multiplexed from the audio input / output device
Is written into the cell assembling memory 14 in the first payload generation unit 13 through The data information is written to the data information memory 16 in the second payload generation unit 15. The payload generated by any of the first and second payload generation units 13 and 15 is selected by the selection unit 17, and the cell header H generated by the cell header generation unit 18 is added to the selected payload, and the selected payload is used as an ATM cell. Sent out.

[0008] The switching means 12 switches between audio information from the audio input / output device 11 and data information from the second payload generation unit 15 and supplies the data to the first payload generation unit 13. The first payload generation unit 13 stores the input information in the memory 14
For example, for voice information, a voice packet is formed by adding a header h such as a channel identifier and a burst length to the compressed voice for each frame, and a voice packet formed in the order in which only voiced information is supplied is stored in a cell. To form a payload. When not only voice information but also data information is supplied to the first payload generation unit 13, a data packet is formed by the data information, and this is packed in a cell together with the voice packet.

The second payload generator 15 configures the supplied data information as a payload, that is, the memory 1
From 6 to 1 cell of data information, the selection unit 17
, And a requested amount or a predetermined amount of data information can be packed out of the memory 16 and supplied to the switching means 12. The switching of the switching means 12 is controlled by the voice / data transmission control unit 19, and a voice information transmission request is issued to the cell transmission control unit 21. The data transmission request is sent from the second payload generation unit 15 to the transmission control unit 1.
The voice / data transmission control unit 19 controls the switching unit 12 to supply data information to the first payload generation unit 13. When the voice information transmission request is input, the cell transmission control unit 21 always causes the selection unit 17 to select the payload from the first payload generation unit 13,
If only a data information transmission request has been input, a payload from the second payload generation unit 15 is selected. The data information transmission request is generated under the control of another control means.

For example, when a cell becomes empty in the first payload generation unit 13, a data information transmission request is issued from the second payload generation unit 15 via another control means, and the data information is packed out from the memory 16. With this configuration, a cell can be assembled with voice information, and a cell can be assembled with data information. In addition, when a cell is assembled with voice information, data information is sent to the first payload generation unit 13 when a vacancy occurs. It can supply and fill the empty space with packets of data information. Alternatively, a predetermined amount of data information may be packed in a cell together with a voice packet in advance, although no space is generated.

FIG. 2 shows an embodiment of the packet disassembly apparatus of the present invention. The received ATM cells are temporarily stored in the reception cell processing memory unit 25 and analyzed by the header analysis unit 26 from which the header H is extracted from the memory unit 25. The selecting means 27 is controlled in accordance with the analysis result. In the case of a voice information cell, the payload in the memory unit 25 is supplied to the separation unit 28, and in the case of a data information cell, the payload in the memory unit 25 is supplied to the data processing unit. 29.

The separating unit 28 stores the input payload in the cell disassembly memory 31 and separates it into information for each packet. The separated information is supplied to the audio input / output device 33 by the separating means 32, and the data information is supplied to the data processing unit 29. The header analysis unit 26 detects which packet in the cell is a data packet, and supplies the data packet to a voice / data distribution control unit 34. The control unit 34 separates and outputs voice information from the voice packet. During the period, the separation means 32 is connected to the voice input / output device 3.
3 and when the data information of the separated data packet is output, control is performed so that the classification means 32 is supplied to the data processing unit 29.

The data processing section 29 stores the input data payload or the data information from the classification means 32 in the data information memory 35 and packs it out as data information of a required speed. In this way, both the cell containing only voice information and the cell containing only data information can be decomposed into cells, and even when the data information is incorporated into the cell together with the voice information, the cell is separated into these voice information and data information. Can be output.

Next, an embodiment of the cell conversion method according to the present invention will be described. As shown in FIG. 3A, when the compressed voice information is packetized and the voice packets # 1, # 2, and # 3 are incorporated in the cell, the cell assembling time limit is reached. At this time, no voice packet is generated. In this case, data corresponding to the free space of the cell is packed out from the data information memory 16 and this is packed in the cell as a data packet. In this way, cells can be transmitted with voice information and data information in a full cell within the cell assembly time limit, and highly efficient voice communication can be performed without deteriorating voice quality.

As shown in FIG. 3B, the data information is divided into fixed lengths in advance, the voice packets are packed into cells, and when a cell is vacant within the cell assembly time limit, the data information is fixed from the data information memory 16. The long data is taken out, packetized and packed in a vacant part. If the vacant capacity is smaller than the fixed length data, the data information Ds overflowing from that cell is transferred as a data packet to the next cell to be assembled. Jam.

As described above, when a voice packet is packed,
If the data information is packed only when a vacancy occurs, the amount of data information transmitted is small, and if sufficient data information cannot be sent, as shown in FIG. 4A, the data information is packed before the cell assembly time limit. The amount of voice packets is limited to a predetermined value, the capacity of cell vacancies is increased, and fixed length data or variable length data is packed as data packets.

As shown in FIG. 4B, data packets are filled in the empty space generated during the cell assembling time limit, and the insufficient data information may be sent out by forming an ATM cell by itself. Good.

[0018]

As described above, according to the method of the present invention, not only voice packets but also data packets are packed in one cell, so that voice information and data information can be effectively transmitted in one cell. . Also, when a cell is mainly composed of voice information, if a cell vacancy occurs due to a relationship between a cell assembly time limit and an irregular length of the voice packet,
Since this part is packed with data packets, efficient transmission is possible.

According to the cell assembling apparatus of the present invention, it is possible to assemble a cell with only voice information or a cell with only data information, and assemble one cell with both a voice packet and a data packet. And the above-described method of the present invention can be carried out. ADVANTAGE OF THE INVENTION According to the cell disassembly apparatus of this invention, it is possible to perform cell disassembly on either a cell containing only audio information or a cell containing only data information. Can be decomposed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of an embodiment of a cell assembling apparatus of the present invention.

FIG. 2 is a block diagram showing a functional configuration of an embodiment of the cell disassembly apparatus of the present invention.

FIG. 3 is a diagram showing an embodiment of the cell conversion method of the present invention.

FIG. 4 is a diagram showing another embodiment of the cell conversion method of the present invention.

FIG. 5 is a diagram illustrating a state in which compressed audio is multiplexed and packed into cells.

FIG. 6 is a diagram showing a state in which a cell becomes empty due to a cell assembly time limit.

Claims (5)

[Claims] 1. A cell conversion method in which voice information is packetized and the packet is packed in a cell, wherein a packet of data information is also packed in the cell. 2. The method according to claim 1, wherein said data packet is packed in a vacant cell generated during a cell assembly time limit.
Described speech information cell conversion method. 3. A fixed length data packet is prepared in advance,
3. A voice information cell conversion method according to claim 2, wherein said fixed length data packet is packed in said empty space, and overflowing data information is packed as a data packet in a cell to be assembled next. 4. A first payload generating means for receiving voice information and generating a payload, a second payload generating means for receiving data information and generating a payload, and replacing the data information with the voice information. Switching means for supplying to the first payload generating means; selecting means for selecting one of the generated payload of the first payload generating means and the generated payload of the second payload generating means; A cell header generating means for adding a cell header; 5. Separating means for separating an input payload into information for each packet, data processing means for outputting data information from the input payload, analyzing a header of a received cell, and A cell disassembly apparatus comprising: a header analysis unit that supplies a payload to the separation unit or the data processing unit; and a unit that separates voice information and data information separated by the separation unit.