JPH02179040A - Digital line concentration system - Google Patents

Abstract

PURPOSE:To increase number of channels able to be concentrated by providing a transmission quantity variable means varying the quantity of transmission information per channel sent in a unit time, and varying the maximum accommodation channel number. CONSTITUTION:The maximum accommodation channel number of a digital line concentrator 1 is normally 30, the quantity of information transmission per channel is 64kbit/s and the transmission capacity of a high speed digital transmission line is 2[Mbit/s]. When the traffic exceeds the maximum accommodation channel number 30, a transmission quantity variable means 2 reduces the transmission information quantity of 64kbit/s for each channel into 32kbit/s. The transmission quantity for one second in this case is 32[kbit]X60-channel and the line concentrator 1 is connected to the high speed digital transmission line of 2[Mbit/s] the same as the normal case. Thus, the maximum accommodation channel number is increased to 60 in this way.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a digital concentrator system for time-division multiplexing digitized signals of a plurality of subscriber channels onto a higher-speed digital transmission path. .

(Prior Art) In the conventional digital concentrating system, when traffic occurs, the digitized signal of a specific subscriber channel is transferred one-to-one to the time slot for the specific channel on a higher-speed digital transmission path. The method used was to perform digital line concentration by allocating data according to the relationship between the two and multiplexing the same amount of transmitted information.

[Problem to be solved by the invention]

In the conventional digital line concentration system described above, the amount of information transmitted per unit time for each channel on the high-speed digital transmission path is equal to the amount of information transmitted by digitizing subscriber signals in each subscriber channel. Therefore, the maximum number of channels that can be accommodated on the high-speed digital transmission path is fixed.

Therefore, when traffic exceeding the maximum number of accommodated channels occurs, a problem arises in that the line concentration service cannot be provided for the traffic exceeding the maximum number of accommodated channels.

[Purpose of the invention]

The present invention aims to solve the problems of the prior art, and provides a digital line concentration method that increases the number of channels that can be concentrated by making the amount of information transmitted for each channel variable. To make an offering,
That is the purpose.

(Means for Solving the Problems) In the present invention, in a digital concentrator that accommodates a plurality of digital subscriber channels and connects them to a high-speed digital transmission path, the amount of transmitted information per channel transmitted per unit time is changed. The configuration is such that the maximum number of channels that can be accommodated is made variable.

This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a digital line concentrator 1 which is an embodiment of the present invention.
This shows the configuration of .

In FIG. 1, the digital line concentrator 1 normally accommodates a maximum number of channels of 30, and the amount of transmitted information per channel is 64 Kbit/S.
The transmission capacity of the high-speed digital transmission line is 2 (Mbit/
S).

FIG. 2 is a time chart showing transmission signals in the digital line concentrator 1 shown in FIG.
) shows the normal state, and (B) shows the case where the traffic exceeds the maximum number of channels that can be accommodated.

Normally, each frame consists of an overhead pit followed by 30 channels of data with channel numbers 1 to 30, and the number of frames per second is from the first frame to
64.000 of the 64.000th frame (frame)
Therefore, in one second there are 64 (Kbit) xa
O channel data is transmitted and 2 CMbtt
/s) is connected to a high-speed digital transmission line.

When the traffic exceeds the maximum number of accommodating channels, 30, the transmission amount variable means 2 changes the amount of information transmitted for each channel from 64 (Kbit/S) to 32 (Kbt/S).
t/S). Each frame consists of a first overhead bit followed by channels with channel numbers 1 to 30, and a second overhead bit followed by 30 channels with channel numbers 31 to 6o, and the number of frames per second is from the first frame to 32. of the 32,000th frame. .

00 frame. In this case, the amount of transmission per second is 32
(Kbit) x60 channel, and is connected to a 2 (Mbit/S) high-speed digital transmission line as in normal times.

As described above, in the embodiment shown in FIG. /S), the maximum number of accommodated channels can be increased to 60 channels.

In order to reduce the amount of transmitted information, the digitized subscriber signal can be decimated in half in groups of quantized data and allocated to channel time slots on the high-speed digital transmission line ( By doing this, it becomes possible to maintain line concentration services even when the line quality deteriorates to some extent or when traffic suddenly increases.

Note that the upper part allocates digitized subscriber signals to channel time slots on a higher-speed digital transmission path in a 2:1 ratio, but is not limited to this (4:1, 4:1, etc.). The number of channels that can be condensed can also be increased by 4 times, 8 times, . . . by allocating 8 to 1.

[Effects of the Invention] As explained above, according to the present invention, in a digital concentrating system in which multiple subscriber channel signals are time-division multiplexed onto a higher-speed digital transmission path, the amount of information transmitted per channel transmitted per unit time is reduced. is made variable to increase the maximum number of channels that can be accommodated, so even if the quality of the transmission path deteriorates to some extent when traffic exceeding the maximum number of channels that can be accommodated occurs, line concentration and connection services can be maintained. be able to.

Therefore, according to the present invention, even when traffic becomes abnormally high in an emergency or the like, a digital line concentrator or the like that handles subscriber voice signals can provide line concentrator services while maintaining a certain level of line quality. It is possible to provide an excellent digital line concentration system that is not available in other countries.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 (A
) and (B) are time charts showing transmission signals in the embodiment of FIG. 1, respectively. 1...Digital line concentrator, 2...Transmission amount variable means.

Claims (1)

[Claims] (1) A digital line concentrator that accommodates multiple digital subscriber channels and connects them to a high-speed digital transmission line is equipped with a transmission amount variable means that changes the amount of information transmitted per channel per unit time, and A digital line concentration method characterized by a variable number of channels.