JPS6362927B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a multipurpose local communication system that performs communication by time-division multiplexing digitally encoded voice, non-voice data, facsimile, and other information on the same transmission path, which multiplexes channels. This invention relates to a controlled time division multiplex communication system.

Conventionally, digital multiplex communication technology for local area communication has often been seen in the field of data communication, and the multiplex frame structure in the line conversion method using channel multiplexing as a multiplexing method is simply multiplexing channels at the basic transmission rate. and
All control signals are transmitted within the channel. In this configuration, the content of one channel may mean a control signal or communication information, and it is necessary to identify both using a terminal device, a communication control device, or the like. Furthermore, if it becomes necessary to transmit some kind of control signal during communication, the transmission of communication information must be temporarily interrupted and the control signal must be transmitted. In the case of only data communication, this problem does not arise at all by buffering the data, but it becomes a major drawback in cases where immediacy is required, such as in voice calls.

In addition, when multiplexing voice information and data information simultaneously, if the basic transmission speed of the channel is set low as in data communication, when transmitting voice information, many channels must be used simultaneously. Therefore, there is a possibility that the number of channels required for audio transmission cannot be secured, and since it is not always possible to use continuous channels, there are drawbacks such as complicated control. On the other hand, if the basic transmission speed of the channel is adjusted to the transmission speed of voice information, even when transmitting data information whose transmission speed is much lower than that of voice,
This has the disadvantage that the channel is monopolized and the transmission path is not effectively utilized.

In order to solve these drawbacks, the present invention has a multiplexed frame structure in which a voice information channel, a data information channel, and a control signal channel constitute one frame, and a plurality of frames constitute one multiframe. In order to allocate a control signal channel corresponding to each information channel, and further divide the data information channel into multiple subchannels, and to secure a control signal channel corresponding to the subchannels, one superframe is made up of multiple multiframes. The present invention provides a time division multiplex communication system that improves channel usage efficiency by controlling an arbitrary number of subchannels so that one terminal can use them simultaneously.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is an embodiment of the present invention, and shows a multiplexed frame structure in a matrix form. 1 to 64 are time slots, and the data are transmitted consecutively in numerical order. The time slots 74 to 81 in the column direction of the matrix are respectively channels, and the time slots 65 to 72 in the row direction are frames. That is, time slots 1, 9, 17, 25, 33, 41, 49, and 57 are used as control signal channel 1, time slot 2,
10, 18, 26, 34, 42, 50, 53 are control signal channel 2, time slot 3, 11, 19, 27, 35,
43, 51, 59 are audio information channel 1, time slots 4, 12, 20, 28, 36, 44, 52 are audio information channel 2, time slots 5, 13, 21, 29,
37, 45, 53, and 61 are audio information channels 3, and time slots 6, 14, 22, 30, 33, 46, 54, and 62 are audio information channels 4. Time slots 7, 15, 23, 31, 39, 47, 55, 63 and 8, 16,
Each channel for data information consisting of 32, 40, 48, 56, and 64 is divided into 8 subchannels in units of time slots. That is, time slot 7
is subchannel 1, time slot 8 is subchannel 2, time slot 15 is subchannel 3, time slot 16 is subchannel 4, and so on.
24, 31, 32, 39, 40, 47, 48, 55, 56, 63, 64, respectively, to subchannels 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15 and 16.

In addition, 65, which is the sum of numbers 1 to 8, is frame 1, and 66 to 72 are frames 2 to 8 in the same manner. A total of 73 frames, including frames 1 to 8, are considered multi-frames, and the first
Although the figure shows only multiframe 1, multiframes 2 to 4 having a similar configuration follow, and multiframes 1 to 4 constitute a superframe. This one superframe completes the multiplexing unit, and thereafter communication is performed by repeating this superframe.

In this embodiment, for convenience of explanation, a total of 8 channels, 2 channels for control signals, 4 channels for audio information, and 2 channels for data information, are defined as 1 frame, and 8 frames are defined as 1 multiframe. 4
Although an example is given in which the multiframe is one superframe and the number of subchannels is 16, these numbers are not limited to these and can be arbitrarily determined.

Next, allocation of information to channels will be explained. The control signal channel is a channel for transmitting control signals for call setup, hold/transfer, etc. during a call, and the voice information channel is a channel for transmitting digitally encoded voice information. The data information channel is a channel for transmitting data other than voice, information such as facsimile, etc. For the data information channel, it is possible not only to set a communication path in each channel, but also to divide each channel into eight equal subchannels 1 to 16, and set a communication path in each subchannel.

The method of allocating control signals to the control signal channels is to allocate them corresponding to each channel or subchannel. That is, control signals related to audio information channel 1 are assigned to the control signal channels of frame 1 (1 and 2 in FIG. 1), and audio information is assigned to the control signal channels of frame 2 (9 and 10 in FIG. 1). control signals for channel 2 are assigned. Thereafter, up to the control signal channel of frame 4 is used in the same manner. Next, control signals related to subchannels 1 to 4 are assigned to the control signal channels of frames 5 to 8, respectively. This completes the allocation of all control signal channels for multiframe 1. Next, in multi-frame 2, the control signals of audio information channels 1-4 are assigned to the control signal channels of frames 1-4, as in multi-frame 1, and the control signal channels of frames 5-8 are assigned sub-channels. Channels 5-8
Assign control signals. Similarly for multi-frames 3 and 4, the control signals of the audio information channel are assigned to the control signal channels of frames 1 to 4, and the control signals of subchannels 9 to 12 and 13 to 16 are assigned to frames 5 to 8, respectively. Assign. Therefore, during one superframe, control signals for audio information channels are allocated four times to each channel, control signals to subchannels are allocated once to each channel, and control signals for all channels and subchannels are transmitted.

Next, an example of how channels are used for communication will be explained. FIG. 2 shows an example of a multi-purpose local communication system using the multiplexed frame structure according to the present invention, in which 101 is a control device that controls the entire system and connects to outside lines, 102 to 104 are digital telephones, data 105 is a loop transmission line; 106 is a terminal device such as a terminal device or a facsimile device;
is an outside line. Time division multiplex communication using the multiplex frame structure of the present invention is performed on the loop transmission path.

A bit indicating the empty/busy state of the information channel is provided in the control signal channel to display the empty/busy state of the channel, and each terminal constantly monitors this. When a terminal makes a call, the terminal occupies the information channel and the corresponding control signal channel by detecting an empty channel, rewriting the channel status display to "occupied", and capturing the channel. The calling terminal sends a calling signal, the other party's address, etc. into a control signal channel, and the receiving terminal returns a response signal. When a communication path is formed using such a control signal channel, actual information is transmitted and received using the information channel. If a control signal such as hold/transfer is required during communication, it is transmitted using a control signal channel. When the communication ends, the control signal channel is used to perform call termination processing, and finally the channel status display is rewritten to empty to release the channel.

Even in the case of communication using a subchannel, communication can be performed using exactly the same procedure as in the case of the channel. Since the empty state of the channel is displayed on the control signal channel, terminal 1 can have the function of capturing and releasing the channel, and when using multiple subchannels at the same time, the calling terminal By notifying the called terminal of the subchannel number to be used, an arbitrary number of subchannels can be used, and a transmission rate that better matches the communication speed of the terminal can be selected.

As explained above, according to the present invention, a data information channel that can be divided into subchannels and controlled in units of subchannels for low-speed digital information other than voice is provided, and a voice information channel and a subchannel are provided. Since control signal channels corresponding to the channels can be assigned, it is easy to use any number of subchannels simultaneously on one terminal, and the transmission speed of the communication path can be selected according to the communication speed of the terminal. In a system in which voice and low-speed digital information other than voice are time-division multiplexed and transmitted over the same transmission path, channel usage efficiency can be significantly increased, and there are advantages in that control for selecting the transmission rate is simple.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a configuration of a multiplexed frame according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the configuration of a multipurpose local communication system using the multiplex communication system of the present invention. 101...control device, 102-104...digital telephone, 105...loop transmission line, 106
...External line.

Claims (1)

[Claims] 1. A plurality of digital telephones each having an analog-to-digital converter for encoding voice, a data terminal device, an image terminal device, and a composite terminal device that combines the functions of these terminal devices. In a digital communication system that connects one or more types of terminals simultaneously and communicates by time-division multiplexing using the same transmission path, each time-divided time slot is continuously
One for control signals for transmitting control signals between a control device and a terminal device and between terminal devices, one for audio information for transmitting digitally encoded audio information, and one for transmitting digital information other than audio. A frame is configured by allocating data information, each time slot allocated for audio information in the frame corresponds one-to-one to each audio information channel, and a multi-frame is generated from a plurality of the frames. The time slots for each data information within a multi-frame are made to correspond one-to-one to each subchannel for data information, and the time slots for control signals within a multi-frame are first Allocate control signal channels corresponding to all of the audio information channels, then reserve the remaining control signal time slots for data information subchannel control signals, and Multiple multiframes are collected to form a superframe until a control signal channel corresponding to all the data information subchannels in the multiframe is assigned to the time slot reserved for the multiframe, and the superframe is further connected to the transmission path. In order to make it possible to select a transmission speed suitable for the communication speed of a terminal device, one terminal device can use any number of subchannels of one or more at the same time, thereby achieving communication with a transmission speed that is an integral multiple of the transmission speed of the subchannel. A time division multiplex communication system characterized by having means for forming a channel.