JPS62254550A - Voice packet communication system in loop transmission system - Google Patents

Abstract

PURPOSE:To improve transmission service by inserting a voice packet between components by the reception of a token circulated through a transmission line to reduce the delay of transmission as far as possible. CONSTITUTION:An analog voice signal sent to data transmission stations A-E is sampled at each prescribed time, converted into a digital code to constitute the voice packet. The token circulated through the transmission line is caught by the stations A-E and a variable length time division area is provided in the token itself to insert the formed voice packet. Further, the voice packet inserted to the token is sent in the cyclic time of the token and since the cyclic time of the token is specified within a desired constant time, the delay of transmission is decreased. Further, the transmission service is improved without applying processing causing the reduction in the transmission efficiency of the network.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a voice packet communication method used in a loop transmission system in which a plurality of data transmission stations are connected in a loop via a transmission path.

BACKGROUND OF THE INVENTION Conventionally, various methods have been provided for transmitting and receiving data between a plurality of data transmission stages.

For example, one such method is a token passing method in which these data transmission stations are connected in a loop and transmission rights are acquired by receiving tokens. Unlike other data, when transmitting voice data, there is a need to reduce the amount of information and ensure real-time performance, so a transmission method using time division access has been particularly used. Transmission of audio packets in the above)-Kunpassing method requires complex processing such as a communication method that does not transmit audio packets determined to be silent packets and a communication method that compresses and transmits audio data.

Furthermore, since voice packets require more immediate response than data packets, in networks where voice and data coexist, voice packets must always be transferred with priority over data packets.

Problems to be Solved by the Invention In such prior art, the voice packet communication system first receives a token circulating on a transmission path at a data transmission station, and then inserts voice into the data packet. Also, unlike normal data communication,
Since the amount of information in voice communication is quite large, there is a problem that the transmission delay of the voice packet F is large, and the compression method causes loss of voice information.

Furthermore, since the voice packet F is always given priority over the data packet, there is a problem that the transmission efficiency of the normal data packet may be reduced.

An object of the present invention is to improve the transmission service in the transmission of voice packets without performing processing that reduces the transmission efficiency of the network, such as giving priority transmission rights to the voice packets over other data packets. An object of the present invention is to provide a voice packet communication method in a loop transmission system that reduces delay.

Means for Solving the Problems The present invention connects a plurality of data transmission stations that send and receive data in a loop via a data transmission path,
Upon reception of the token circulating on the transmission path, the data transmission stage 3 acquires the transmission right, inserts an audio packet between the following components in the time series of the token by time division, and transmits it together with the token. This is a voice packet communication method in a loop transmission system.

Operation: The analog audio signal transmitted to the data transmission stage 1 is sampled at regular intervals and converted into digital codes to form audio packets.

Here, the data transmission stage 1 captures the token circulating on the transmission path, and by providing a variable length time division area within the F-kun itself, the configured voice packet can be inserted.

Furthermore, the voice packet inserted into the token is transmitted during the token's circulation time, and the token circulation time can be defined within a desired fixed time, so that the transmission delay is reduced.

Embodiment FIG. 1 is a diagram showing the configuration of a loop transmission system according to the present invention. A token, which is a signal indicating the idle state of the loop, circulates on a transmission path formed by connecting data transmission stages A to E in a loop to send and receive data. In addition, the data transmission stage 1A includes a terminal device AI such as a handset/receiver.

A2. ..., An is installed. Similarly, a plurality of terminals are connected to each data transmission stage 1-E. In FIG. 1, the broken line J! AB, 7BC
1 shows an example of a transmission path for audio packet F. In other words, the broken line 7AB is the terminal device A1 of the voice bucket) VP.
The broken line 7BC from VP to terminal B1 is the audio bucket)
This is a transmission path from terminal device B3 of No. 2 to terminal device C2.

tJ112 is a block diagram showing a data transmission stage 1 A for transmitting voice packets and a handset A1 which is a terminal device, which implements the present invention. This example uses a telephone codec 2. For example, it is used as a stage for a local area network.

In FIG. 2, a handset/receiver A1 is connected to the codec 2 via a transmitting amplifier 3 and a receiving amplifier 4. In FIG.

The codec 2 consists of a code 3 (COD) and a decoder (DEC).

Codec 2 is RAM5. Control n1 configured by CPU 6, network controller 7, etc.
It is used to send and receive audio data to and from. The timing circuit 9 includes the codec 2, the RAM 5, and the CPU.
Outputs a synchronization signal to synchronize with control 8.
1, voice packets are generated at regular time intervals by this synchronization signal. The network controller 7 is connected to a transmitter/receiver 8, and the transmitter/receiver 8 transmits and receives information to and from the network.

FIG. 3 is a diagram illustrating the encoding of the codec 2. The audio signal, which is an analog signal, is -■ Porto ~ +■
It has an analog level up to volts and can be converted via codec 2 into, for example, a 256-level digital code (008 to 8
0H).

The conversion of this codec 2 may be a method of converting analog levels at fixed time intervals corresponding to one code,
Weighted code conversion depending on the analog level may also be used.
Here, in 256-level digital encoding, the conversion from -V volts to O volts at the analog level is 16
It is assumed that OOH corresponds to 7 F H in the base system, and conversion from 10 volts to 0 volts corresponds to 80H to FFH.

FIG. 4 is a diagram showing a series of operations using data 70-. The line 71 in FIG. 4(1) corresponds to the handset A1 in FIG.
This shows the analog waveform of the audio signal input from the data transmission stage 1A to the data transmission stage 1A, which is converted into a digital code using a codec 2 or the like.

Figure (2) shows the line J! This is an 8-bit digital code string obtained by sampling the audio signal of i by codec 2 at, for example, 8 kHz.

For example, in (1) of the same figure, the value of the analog level at time t1 is +L1, which is 8kHz.
At time t2, for example, 125 pSee after one time t1, which is converted into an 8-bit digital code "EOH" by sampling, the analog level is +L2, and the analog level is sampled and converted into a digital code [C311J+]. Similarly, digital codes corresponding to analog levels sampled every 125 μS e are shown below.

Here, although the analog level +L2 at time L2 is larger than the analog level L1 at time L1, in the converted digital code, time t1 (EOH) is higher than time t2 (C3H).
) indicates a value larger than 80H to F when converted to digital code.
This is because it is said to be compatible with FH.

Figure (3) shows the process in which sampled data is inserted into a time division area within a token and transmitted to the other station. When stage aA is reached, the token is captured by changing the data FLAG, which will be described later, which is one of the token access controls, and a time-sharing area is created within the token itself, in which the sampled area is stored. Insert the voice packet that was Thereafter, the voice packet inserted into the token is transmitted at the token circulation speed.

Furthermore, in the token passing method, since the token circulation time can be defined within a certain period of time, voice data can arrive at the other party's station at certain intervals without delay. That is, for example, if the time interval of audio sampling is 125 μSe
If it is e, by specifying the token circulation time within 125μSee, it is possible to prevent variations in the 11f1rIl interval when voice packets arrive at the partner station.

FIG. 4(4) shows a digital code string obtained by recombining voice packets F that have arrived at the opposite station (for example, data transmission stage 1B) in chronological order. The configuration of the terminal equipment (for example, the transmitter/receiver 3B1) of the data transmission stage a and B is the same as that shown in FIG. 2, and therefore the same reference numerals will be used hereinafter.

In FIG. 5 (5), a line 72 represents the analog waveform output to the handset B1, that is, the digital code input to the codec 2 is converted to an analog level and sent to the handset B1. Here, the generation and reproduction of the audio data is performed at every 125 μSee timing of the codec 2, and is performed without synchronization with the arrival of the token.

Next, the present invention will be applied to the international standard IEEE802.
．． An example applied to No. 5 will be described.

FIGS. 5(a) and 5(b) are diagrams schematically representing the token format (format) and frame format in IEEE802.5, respectively.

The l-kun format is formed by an SD (start delimiter) 10, an AC (access control) 11 and an uplink ED (end delimiter) 17. The frame format is a format in which data is inserted into the token format by converting the 7-lea sequence into a pino-)-kun (7-order sequence), so the following is the same structure and element as the second token format. The same references are given to

The frame format is S, which consists of 5DIO and ACII.
F S (7-frame leap start sequence) 19 and FC
(7 frame control) 12, DA (destination address) 13, S
A (source address) 14, INFO (information) 15 and FCS (7 frame check sequence) 16 inspection distribution area 20 consisting of A (source address) 14, INFO (information) 15 and FCS (7 frame check sequence) 16, as well as ED17 and FS (7 frame check sequence) 18
E F S (7 frame ending sequence) consisting of 21
It is formed by

FIGS. 6(a) and 6(b) show the IEEE80
2.5 is a diagram schematically showing an embodiment in which the present invention is applied to a 7-rem format and a 7-rem format.

The figure (,) shows the A in the token format of Figure 5 (,).
1 audio bucket between Cll and ED17) VP,
, V P 2. -, with insertion of V P n22.

Similarly, FIG. 6(b) shows that n voice packets V P ,, V P , . . . , V
Pn22 was inserted.

That is, by providing a time division area within the token and 7-frame format itself and inserting audio packets into the time division area, audio packets can be transmitted at the token circulation speed.

Here, +1 audio packet is inserted, so by changing the length of the token and frame format according to the amount of audio data, audio data can be inserted into the token regardless of the amount, Can be transmitted.

Furthermore, we will give examples in which the present invention is applied to other token formats (Figures 7(a) and 7(1)) are diagrams schematically showing 7-day token formats and busy token formats, respectively. It is. The token format is FLAG23.
AC24 (for +, hexadecimal denotal code 1FOF
(represented by OJ), CRC+ (cyclic redundancy check) 25
, CRC226 and FLAG27.

The Pino-token consists of FLAG23 and AC24 (also denoted by 0FOJ), CRC+25 and ABORT28.

FIG. 8 is a diagram schematically showing an embodiment in which the present invention is applied to the token format. Figure 8 (a) and Figure 8 (
b) 11 in each AC24 of said token format.
voice packets v p ,, v p ,,...,■
It is a figure showing the state where Pn29 was inserted. In this case, the AC24 is represented by "FOFOJ", and n voice packets are inserted between them, but the insertion location can be arbitrarily selected between the AC24s or immediately after the AC24.

In addition, in order to make the time division area variable, the agreement with the partner station regarding which number of VPn to use (n voice buckets) V P 1tV P 2-..., VPn is determined using the conventional F-Kunpassing method. This can be determined by the exchange of data in the method.

Effects As described above, according to the present invention, transmission delays can be reduced as much as possible by inserting voice packets into tokens whose circulation time is defined as short. Furthermore, since only tokens are used to transmit voice packets, as a result, the token length does not have to be prioritized over other data packets, and there is little need for normal packet transmission. You will not be given a colored tube.

Furthermore, the van 7a used for delay absorption becomes unnecessary.

[Brief explanation of drawings]

FIG. 1 is a three-dimensional diagram of the loop transmission system according to the present invention.
Figure 2 is a block diagram of a transmission station that transmits voice packets and a handset, Figure 3 is a diagram showing codec encoding processing, Figure f54 is a data flow showing a series of transmission operations, and Figure 5 is an IEEE802 A diagram of the token and frame format in .5, Figure 6 illustrates the present invention
FIG. 7 is a diagram showing the application of the present invention to the Y-kun and frame formats in E802.5, FIG. 7 is a diagram of the 7 Lee token and busy token formats, and FIG. 8 is a diagram of the present invention applied to the 7 Lee token and busy token formats.

Claims (1)

[Claims] Multiple data transmission stations that send and receive data are connected in a loop via a data transmission path, and by receiving tokens circulating around the transmission path, the data transmission station acquires the right to transmit, and by time-sharing the tokens. An audio packet communication method in a loop transmission system characterized by inserting audio packets between constituent elements in a time series and transmitting them together with tokens.