JPH0336478B2 - - Google Patents

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (Fig. 1) Function Examples Effects of the Invention [Summary ] In a time-division switching system, a low-speed time switch is provided at both ends of the high-speed communication network, and by rearranging the data of the low-speed call on the same phase of each high-speed frame, the low-speed time switch is used to arrange data on the same phase of each high-speed frame. The same channel of each high-speed frame is shared by N different types of low-speed call data, thereby reducing the increase in call loss probability and the decrease in processing efficiency.

[Industrial application field]

The present invention relates to a multiple switching system that targets low-speed calls and high-speed calls that require N times the transfer speed, and in particular combines a high-speed communication path that operates in units of high-speed frames and a low-speed time switch that operates in units of low-speed frames. The present invention relates to an exchange system configured with

In the following description, F _H is a fast frame, F _L
is a slow frame whose time length is N times F _H (N is a positive integer), T _L is a slow time switch, S _L is a slow space switch, T _H is a fast time switch, and S _H is a fast space switch. .

[Conventional technology]

Conventionally, as a multiple switching system that handles both low-speed calls and high-speed calls, T _L −S _L − exchanges data in F _L units.
Either a low-speed communication path with a T _L configuration or a high-speed communication path with a T _H -S _{H -TH} configuration in which data was exchanged in _FH units was used.

[Problem that the invention seeks to solve]

Problems with the above conventional structure will be explained with reference to FIGS. 6 and 7.

FIG. 6 is a diagram showing problems with the conventional T _L -S _L -T _L configuration. In FIG. 6a, the data in each time slot TS on the highway is switched in _FL units, and each frame _FL includes a large number of time slots TS. Low speed call data A, B,
C are each transmitted using one time slot in each slow frame F _L. On the other hand, high-speed call data is transmitted using a plurality of time slots (four indicated by diagonal lines in the figure) within the _FL . In this way, even data from a high-speed call (in the figure, the speed is four times that of a low-speed call) can be transferred over the low-speed communication path.

However, as shown in Figure 6b, T _L −
In the S _L -T _L configuration, when exchanging information on different highways in S _L , the same phase is created on the primary link that inputs information to S _L and the secondary link that outputs information from S _L. need to find it. For low speed calls, F _L
Connection is possible if there is one free time slot of the same phase within the same phase, but a high-speed call cannot be connected unless there are multiple free time slots of the same phase (four in the example of Figure 6a). The internal call will be lost.
In FIG. 6b, there are three vacant time slots of the same phase, but high-speed calls that require four or more time slots within 1 _FL will be lost. In this way, T _L −
In the S _L -T _L configuration, the internal call loss probability of high-speed calls is greater than that of low-speed calls, and the connection quality of both calls varies significantly.

Furthermore, although high-speed call data is transmitted using multiple time slots in each _FL , when time slot phase conversion is performed within the switch, the order of the time slots is maintained for the high-speed call data. There is also the problem that control becomes complicated because the

FIG. 7 is a diagram showing problems with the conventional T _H -S _H -T _H configuration. In FIG. 7, data in each time slot TS on the highway is switched in units of high-speed frames _FH . In this case, one low-speed frame _FL is composed of a plurality of (four in the figure) high-speed frames _FH . High-speed call data indicated by diagonal lines is inserted into the same time slot (same phase) of each high-speed frame _FH . High speed frame F _H
When switching is performed in units, considering the number of calls that are switched during the F _L period in which low-speed data is input, the contents of T _H are updated in the F _H period.
The same information on data A will be exchanged repeatedly during the _FL period. In other words, the time slot TS has the same phase as the low-speed call data A shown in the figure.
1, TS2, TS3 are occupied by data A.
There is a problem in that as the volume of low-speed calls increases, the number of calls that can be processed during the _FL period decreases rapidly.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. In the figure, the multiple switching system according to the present invention targets low-speed calls and high-speed calls that require N times the transfer speed, and T _H operates in units of high-speed frames F _H .
_{-S H} -T _H A _{high -} speed _{communication} path with _T
The switch has a -S _H -T _H -T _L configuration. Each switch has a corresponding control memory SCM _L ,
It is designed to be controlled by SCM _H , _HCML , SCM _H , and _SCML . Depending on T _L on the input side, each F _L
N different time slots of the low-speed call within a time period N times F _H included in the call are phase-converted so that they exist periodically at intervals of F _H length.

Using the high-speed communication path with the T _H -S _{H -TH} configuration, time slot phases are exchanged in units of high-speed frames F _H in response to connection requests from the corresponding control memories SCM _H , HC _H , and SCM _H . Depending on T _L on the output side,
In response to a connection request from the corresponding control memory _SCML , the phase of the time slot of the low-speed call is exchanged in units of _FL .

[Effect]

By using an exchange with T _L −T _H −S _H −T _H −T _L configuration, low-speed call data is phase-switched on the same phase in units of F _L at the input side T _L and converted into high-speed call data. They can be treated equally, and one time slot in a high-speed frame can be shared by multiple different low-speed calls or one high-speed call.

〔Example〕

FIG. 2 is a block diagram illustrating a multiple switching system according to an embodiment of the present invention. In Figure 2,
TDSW is a multidimensional time division switch according to an embodiment of the present invention, and two sets of time switches T _L 1-T _H 2 configuration and T _L 4-T _H 5 configuration are connected to the input side of the spatial switch _S H 3. Similarly, two sets of time switches T _H 6-T _L 7 configuration and T _H 8-T _L 9 configuration are connected to the output side. Each time switch T _H and space switch S _H has a corresponding control memory SCM, HCM
controlled by Control memory SCM, HCM is
It is connected to a control device (CC) 11 via an SP bus 10. A common memory 12 for storing subscriber information is connected to the control device (CC) 11.

Data from the high-speed terminal T1 and the low-speed terminal T2 that handle moving images are time-division multiplexed by the concentrator switch LCSW1 and sent to the highway HW1.
Terminal T2 may be a high speed facsimile terminal. Similarly, data from terminals T3 and T4 is time-division multiplexed by concentrator switch LCSW2 and sent to highway HW2. Examples of low-speed terminals include ordinary telephone terminals and personal computers.

Spatial switch S _H 3 has T _L 1-T _H 2 configuration and T _L
One of the outputs of the time switch having the 4-T _H 5 configuration is connected to any of the inputs of the time switch having the _TH 6-T _L 7 configuration and the T _H 8-T _L 9 configuration. The basic configuration of the multi-dimensional time division switch TDSW shown in FIG. 2 is substantially the same as the principle block diagram of FIG. 1, so the following explanation of the operation will be based on the principle block diagram of FIG. 1.

FIG. 3 is a time chart for explaining one embodiment of the present invention. Figure 3a shows the frame format on the input highway HWi shown in Figure 1,
Fig. 3b shows the frame format of the output data (primary) of the input side _TL , Fig. 3c shows the frame format of the output data (secondary) of the output side _TH of the input side _TH , Fig. 3 d is the frame format of the output data (3rd order) of S _H , Figure 3 e is the frame format of the output data (4th order) of the output side T _H ,
Figure f shows the frame format of the output data on the output side T _L , respectively.

F _L is N times the time length of F _H (N is a positive integer).

As shown in Figure 3a, the input highway HWi
In the above, high-speed calls appear on the same phase periodically in F _H units, as shown by the diagonally shaded time slots, and low-speed calls appear on the same phase periodically in F _L units, as shown by A to D. That is, each of the low-speed call data A to D is transmitted using any one time slot in _FL , and appears on the same time slot in consecutive _FL .

As shown in Figure 3b, by T _L on the input side,
The data of these low speed calls are phase swapped so that they are on the same phase within _FH . In the figure,
Low-speed call data A to D are arranged on the same phase within different _FHs . If there are more than N pieces of low-speed call data (four pieces in the figure), the phase can be exchanged to another vacant time slot in a different _FH . In this way, different low-speed call data can be placed on the same phase of all _FHs within one _FL .

Next, as shown in FIGS. 3c to 3e, normal high-speed call switching is performed in units of _FH without being aware of the existence of low-speed call data. That is,
There is an identical time slot of F _H of the secondary link.
_FH is used for low-speed call data A, the next _FH is used for low-speed call data B, the next _FH is used for C, and so on. In this way, high-speed call switching is performed in response to connection requests from the corresponding control memories SCM _H , HCM _H , and SCM _H.
For example, as shown in Figure 3e, low-speed call data A~
D is placed in the last time slot of _FH , and high-speed call data is placed in the first time slot of _FH .

Next, the output side T _L exchanges the phase of the time slot of the low-speed call in units of low-speed frames _{F L in} response to the connection request from the corresponding control memory SCML, and, for example, as shown in FIG. Place each piece of data in the call on the requested time slot.

FIG. 4 is a diagram showing the effect of one embodiment of the present invention. In Fig. 4, the number of calls that can be handled in the example is when _{TL, in which 256 low-speed calls are multiplexed between F L ,} is added to the T _H - S _H - T _H configuration, in which 16 high-speed calls are multiplexed between F _H. The amounts are shown in slow call terms. In this case, the speed ratio N between the high speed call and the low speed call is N=16. As is clear from the figure, in this embodiment, even if the call volume ratio of low-speed calls to all time slots within _FL increases, the processing call volume remains constant at 256, but unlike the conventional example, no additional T _L is added. In this case, as the traffic ratio of low-speed calls increases, the amount of calls that can be handled decreases. Therefore, the effect of adding T _L is extremely large.

In the above description, F _L is assumed to have a fixed length, but it is within the scope of the present invention even if F _L is made variable by the control memory _SCML . In this case, the control device (CC) 1 shown in FIG. 2 is stored in a common memory 2.
SCM _L depending on the load situation of the exchange, such as the number of subscribers.
By controlling F _L time length, F _L =F _H ×n
(n=2, 4, . . . , N). This allows low speed calls to be handled as variable speeds.

For example, when the load on the exchange is light,
As shown in the figure, b is made smaller (in the figure, n
=2) Make the speed of low-speed calls almost the same as the speed of high-speed calls and perform the switching operation. Also, when the load on the exchange is heavy, as shown in Figure 5b, increase n (n = 6 in the figure) to increase the multiplicity of low-speed calls so that more calls can be processed. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by adding T _L at both ends of the high-speed communication path with the T _H - S _H - T _H configuration, control becomes complicated in the multi-source time division switching system. It is possible to reduce the call loss rate without causing any problems, and even if the number of low-speed calls increases, the number of calls that can be processed does not decrease. Furthermore, since the low-speed frame length can be made variable depending on the load condition of the exchange, it is possible to efficiently switch between low-speed calls and high-speed calls.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram showing a multiple exchange system according to an embodiment of the present invention, FIG. 3 is a time chart for explaining an embodiment of the present invention, and FIG. The figure shows the effects of one embodiment of the present invention, Figure 5 is a time chart for explaining another embodiment of the present invention, and Figures 6 and 7 explain problems with the conventional configuration. This is a diagram for F _L ...Low speed frame, F _H ...High speed frame,
T _H ...Fast time switch, S _H ...Fast space switch, T _L ...Slow time switch, TDSW...Multi-dimensional time division switch.

Claims (1)

[Claims] 1. A high-speed communication path with a high-speed time switch-high-speed spatial switch-high speed time switch configuration that operates in units of high-speed call frames, targeting low-speed calls and high-speed calls that require N times the transfer speed. , low-speed time switches that operate in units of low-speed frames with a time length N times the time length of the high-speed frame are provided at both ends of the high-speed communication path to form a low-speed time switch, a high-speed time switch, a high-speed space switch, a high-speed time switch, and a low-speed time switch. Each switch is controlled by a corresponding control memory, and a low-speed time switch on the input side determines whether the low-speed calls within a time period N times the high-speed frame included in each low-speed frame are controlled by the corresponding control memory. The phase of N different time slots is changed so that they exist periodically at intervals of high-speed frame length, and the phase of the time slots is changed in high-speed frame units according to the connection request from the corresponding control memory by the high-speed call. A multiple switching method characterized by converting the time slot of a low-speed call in units of low-speed frames in response to a connection request from the corresponding control memory using a low-speed time switch on the output side. 2. The multiple switching system according to claim 1, wherein the control memory corresponding to the low-speed time switch includes means for making the time length of the low-speed frame variable in accordance with the load of the exchange.