JPH01240096A - Line concentration and line distribution system - Google Patents

Abstract

PURPOSE:To ensure the regularity and continuity of a transmitting information signal by delaying an information signal sent by another time slot which is a changing purpose and switching a transmitted time slot when a coincidence with an information signal sent by a present time slot is detected. CONSTITUTION:In a central unit 10, the prescribed delay is given to a receiving data series from frame-resolved time slots through variable delay circuits 14a-14n and their timings are adjusted. A timing difference detecting part 19 compares a data series received by the time slot which is a changing object with the receiving data series of the same information transmitted by the new time slot which is the changing purpose, and when they coincide, a system control part 18 drives a frame crossover part 15, the receiving data series by the new time slot which is the changing purpose is extracted in place of the receiving data series by the time slot which is the changing object, and the time slot is changed.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a means for transmitting information between a central device and a plurality of concentrating and distributing terminals using a time division multiplexing method. Concentration distribution method (conventional technology) that can effectively change the allocation of time slots for transmitting information during transmission without losing regularity in data arrangement. When constructing a circuit switching network, installing individual communication lines between an exchange and a plurality of terminal devices requires a large amount of equipment expense. Therefore, concentrating and distributing terminals are installed at key points, trunk transmission lines are laid between these concentrating and distributing terminals and the central equipment (switching equipment), and each of the terminal devices is connected to the nearest concentrating and distributing terminal to establish a network. It is being considered to build a Then, time slots are allocated to the concentration distribution terminals that receive data transfer requests from the terminal devices by time-division multiplex access, and information is transmitted between the central device and the plurality of concentration distribution terminals in a time-division manner. communication.

By the way, when constructing a mobile radio communication system as shown in FIG. 4 by applying such a line concentration and distribution method, the base stations 2a, 2b, to 2n, which are line concentration and distribution terminals, communicate with a plurality of mobile stations 3 within the zone. The information signals respectively sent from the central device 1 are transmitted to the central device 1. At this time, in order to minimize the redundant bits required between time slots and increase transmission efficiency,
Each base station 2a, 2b.

It is effective to multiplex (multiframe) a plurality of information signals sent by each of ~2n into one time slot.

In this case 5. Due to the zone change accompanying the movement of the mobile station 3, it becomes necessary to switch to a time slot corresponding to another base station. For example, when the mobile station 3 is located in the service zone of the base station 2a and is transmitting information to and from the central equipment in a time slot formed by the base station 2a, the mobile station 3 is located in the service zone of the base station 2b. If you get into the zone,
This time, it becomes necessary to transmit information to and from the central device 1 via the base station 2b. As a result, it becomes necessary to change the time slot during information transmission from the time slot corresponding to the base station 2a to the time slot corresponding to the base station 2b. Therefore, it is necessary to change the time slot during information transmission.

However, such changes in base stations only cause instantaneous noise at most in analog communication, but in digital communication, which realizes high-traffic information communication with a large number of communication channels, the regularity of data arrangement is Problems arose in that the communication information was lost and the communication information became completely random.

Such problems occur not only in dual mobile radio systems, but also in cases where the frame structure is changed depending on the amount of communication traffic on a transmission path.

In other words, as shown in Figure 5, the frame structure on the transmission path maximizes the number of time slots that can be accommodated in one frame in the case of high traffic, and in order to increase the system utilization rate, data is stored in a large amount of time. A large time slot is allocated for transmission, and conversely, in the case of low traffic, a large time length is allocated as a time slot for system control in order to perform propagation delay control, call connection control, etc. with high viscosity. If such adaptive control of the frame structure is performed, the time slot used for information transmission will be forced to change, and at this time, the above-mentioned problems will inevitably occur.

(Problem to be Solved by the Invention) Conventionally, when information is transmitted between a central device and a plurality of concentration distribution terminals by time division multiple access, it is difficult to change the time slot during the information transmission. The problem was how to do this.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a line concentration distribution system that can effectively change time slots during information transmission using time-division winter melon access. It's about doing.

[Structure of the Invention] (Means for Solving the Problems) The present invention relates to a line concentration distribution system that transmits information in a time-sharing manner between a central device and a plurality of line concentration distribution terminals. When changing the time slot for transmitting, the information signal sent in the first time slot is compared with the information signal sent in the second time slot, and the second time slot is changed according to the comparison detection result. A delay is given to the information signal sent in the time slot, and the information signal sent in the second time slot whose delay is controlled matches the information signal sent in the first time slot. is detected, the time slot for transmitting the information signal is switched to the second time slot.

(Operation) According to the present invention, a delay is given to an information signal sent in another time slot to be changed, and this delay-controlled information signal and information sent in the current time slot to be changed are When a match with a signal is detected, the time slot for transmitting the information signal is switched, so even if the time slot is changed, the regularity and continuity of the transmitted information can be ensured. Furthermore, it is possible to smoothly, simply and effectively switch time slots while minimizing transmission delay time.

(Embodiment) An embodiment of the line concentration and distribution system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration example of a central unit and a line concentration distribution terminal configured by applying the embodiment system, where 10 is a central unit and 20 is a line concentration and distribution terminal.

Although only one line concentration distribution terminal 20 is shown here, a transmission line 3 connecting the central device 10 and the line concentration distribution terminal 20 is shown.
0, a plurality of line concentration and distribution terminals 20 are normally connected. Then, the transmission line 30 is time-division multiplexed accessed between the plurality of line concentration and distribution terminals 20 and the central device 10, and the line concentration and distribution terminals 20
Information is transmitted in a time-division manner using the time slots assigned to 0.

Now, the line concentration distribution terminal 20 basically converts the transmission data input from the terminal devices into multi-frames in the frame composition section 21, and under the control of the system control section 22, transmits data to the central device.
The above transmission data is transmitted in the time slot specified by O. This data transmission is performed by, for example, FSK modulating the transmission data in the modulator 23, placing it on a predetermined carrier to convert it into a burst data signal, and sending it out to the transmission line 30 via the diplexer 24. Further, in order to receive the information signal transmitted from the central device 10 via the transmission line 30, the transmitted data is taken in via the diplexer 24, and the data is demodulated by the demodulator 25. The frame decomposition unit 26 decomposes the multi-framed received data into its original frame format.

On the other hand, the central device 10 takes in the data transmitted in a time-division manner from each concentration distribution terminal 20 via the diplexer II, and demodulates it in the demodulator I2. The demodulated received data is then decomposed into each time slot by the frame decomposition unit 13, and the received data of each time slot is transferred from the variable delay circuits 14a to 14n, which will be described later, to the frame switching unit 1.
5.

Then, the exchange control is performed by replacing the time slot of this received data with the time slot assigned to the line concentration distribution terminal 20 as the communication destination.

The data subjected to such exchange control is converted into a multiframe for each time slot by the frame synthesis unit 16, and
From the diplexer 11 to the transmission line 3 via the modulator 17
Sent to 0.

The system control section 18 sends and receives communication control information to and from the system $ control section 22 in the line concentration distribution terminal 20, and executes time slot allocation, propagation delay time control, call connection control, etc. This system control unit 18
Accordingly, the frame decomposition unit 13 and the frame synthesis unit 1
The operations of the variable delay circuits 14a and 6 are respectively controlled according to the output of a timing difference detection section 19, which will be described later.
-14n, the amount of delay is controlled, the operation of the frame switching unit 15, etc. are controlled.

FIG. 2 schematically shows the form of information transmission from the line concentration distribution terminal 20 configured as described above to the central unit IO.
Here, an example is shown in which transmission data is multiframed every four frames and information is transmitted.

That is, the transmission data series input to the line concentration distribution terminal 20 is subjected to minimum delay control so that the time required to send the input data to the time slot assigned to the line concentration distribution terminal 20 is minimized, and the transmission data is transmitted over 4 frames. Each frame is combined into a multi-frame and transmitted in the above time slot. This multi-frame formation is performed in order to maximize the number of time slots and minimize transmission delay time. Thus, the central device 10 decomposes the multi-frame data transferred in the above time slots and restores the original data sequence. A predetermined delay is given to this data series by the variable delay circuits 14a to 14n.

By the way, as is clear from the signal diagram shown in Figure 2, the 4 frames of data transmitted in multiframe form are as follows:
It changes depending on the time slot allocated by the minimum delay control. Therefore, if you try to change the time slot for transmitting information while information is being transmitted in a time slot, the unit of cutting out (separation position) of the data to be converted into multi-frames and transmitted will be changed according to the position of the time slot. Not only will this change, but the timing of the data series obtained by decomposing it into frames will also change significantly.

For example, even if the same data series is transmitted, the data transmitted in time slot A is divided into frames as shown in Figure 3, and the data transmitted in time slot B is divided into frames. , a slight deviation occurs in the timing of the data series. If you switch the time slot with such a timing shift and connect the data series before the change and the data series after the change, the regularity of the data arrangement will be lost and an out-of-synchronization state will occur. Data will be played back with
The playback information becomes completely random.

Therefore, in the central unit 10 described above, a predetermined delay is applied to the frame-decomposed received data series from each time slot through the variable delay circuits 14a to 14n, so that the timing can be adjusted. . The timing difference detection unit 19 compares the data sequence received in the time slot to be changed with the received data sequence of the same information transmitted in the new time slot to be changed, and It determines whether the timings match or not, and controls the amount of delay added to the received data series transmitted in the new time slot targeted for change. The amount of delay is controlled by gradually increasing the delay time from zero until the timings match.

Under such delay control, when the received data sequence in the new time slot to be changed under delay control matches the received data sequence in the tom slot to be changed, the system control unit 18 Frame change section 15
to drive. Then, in place of the received data sequence in the time slot to be changed, a received data sequence in a new time slot to be changed is extracted, and the time slot is changed. Thereafter, information transmission in the time slot targeted for change is stopped and that time slot is released for other information transmission, and the above-mentioned information transmission is performed using the time slot corresponding to the newly set base station. continue.

According to the system including the central device 10 configured in this way, while information is being transmitted using the time slot formed between the concentration distribution terminal 20 and the concentration distribution terminal 20, for example, the concentration distribution terminal 20 responsible for transmitting the information To perform time slot switching very smoothly even when the above information needs to be continuously transmitted in a new time slot set for the line concentration distribution terminal 20 when the line concentration distribution terminal 20 is changed. becomes possible.

Moreover, in information transmission by division multiple access using multi-frames of 4 frames at a time, the frame synthesis delay and frame disassembly delay can be up to 3 times depending on the information position in the frame and the time slot position on the transmission path. Although it is expected that a delay time difference of one frame will occur, even when such a large delay time difference occurs, it is possible to switch time slots while ensuring sufficient continuity of the data series. becomes.

As a result, the base station that relays communication between the mobile station 3 and the central device 1 changes, as in the mobile radio communication system described above.
Even if the time slot assigned to the base station is changed, it is possible to reliably continue the information communication, which brings about great practical effects.

Note that the present invention is not limited to the embodiments described above. Although the switching of time slots due to the change of the line concentration distribution terminal has been described here, the requirements for switching the time slots are not particularly limited. The point is that when it becomes necessary to switch time slots, it is sufficient to perform switching control as described above, and it is applicable to switching time slots under various conditions. Also, here we have explained an example in which information is transmitted by converting 4 frames into multiframes at a time, but the number of multiframes, the number of time slots in time division multiplex transmission, etc. can be determined according to the system specifications. .

Furthermore, the location where the variable delay is added is not limited to the central device. The point is that it is sufficient to be able to control the amount of delay of the information signal transmitted to the central unit via the concentrator/distributor terminal based on the results of timing difference detection in the central unit. A variable delay circuit may be provided in the mobile station in question. Further, as a method for detecting a timing difference between data timings of two time slots to be changed and a time slot to be changed, for example, a time stamp may be assigned in advance to each time slot, and detection may be performed based on the time stamp. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, even if it becomes necessary to switch the time slot during information communication during information communication by multiplexed access, the information communication can be interrupted. This brings about great practical effects, such as being able to smoothly change time slots without any problems and allowing the information communication to continue smoothly.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of main parts of a central unit and a line concentration distribution terminal in a communication system that implements a line concentration distribution system according to an embodiment of the present invention, and FIG. 2 shows a form of information communication using multi-frames. FIG. 3 is a diagram schematically showing a timing shift of a frame decomposed data series due to a difference in time slots, and FIG. 4 is a diagram showing a configuration example of a line concentration distribution system applied to a mobile radio communication system. 5 are diagrams for explaining changes in time slots due to changes in the transmission frame configuration. DESCRIPTION OF SYMBOLS 1... Central device, 2a, 2b, ~2n... Base station (concentration distribution terminal), 3... Mobile station (terminal device), 10
...Central device, 20...Line concentration distribution terminal, 30...
Transmission path, 13.26...Frame decomposition unit, 18.21
...Frame synthesis section, 18°22...System control section, 14a, ~14n...Variable delay circuit, 15...
Frame switching section, 19... timing difference detection section. Applicant's agent Patent attorney Takehiko Suzue Figure 4 Figure 5

Claims (1)

[Claims] Information based on a first frame configuration output by an information terminal connected to a line concentration distribution terminal is converted into a second frame configuration at the line concentration distribution terminal and transmitted via a first transmission path. is transmitted to the central device using time division multiplexing, and the central device transmits the data to the third
At the same time, information based on the fourth frame configuration is converted into a fifth frame configuration by the central device, and the information is transmitted through the second transmission line by the time division multiplexing method. In a line concentration and distribution method in which the information is transmitted to a terminal, the line concentration and distribution device converts the above information into a sixth frame structure, and outputs the information to the information terminal, a second frame is transmitted from the information terminal connected to the line concentration and distribution terminal to the central device. information sent through a first time slot in the frame configuration and converted into a third frame configuration; and information sent through a second time slot in the second frame configuration and converted into a third frame configuration. a timing difference detection unit that detects a timing difference between the information converted to the information and the information converted into the second time slot, and a variable delay circuit that delays the information sent via the second time slot according to the detection result by the timing difference detection unit. information sent through the first time slot and converted into a third frame configuration; and information sent through the second time slot and converted into a third frame configuration and delayed by the variable delay circuit. and means for switching a time slot for transmitting the information to the second time slot after the timing difference detection section detects that the information matches the given information. .