JPH0549139B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a digital time division multiplexer (TDM).
...The same applies hereafter), and is a multiplexing method suitable for efficiently multiplexing various types of data with different transmission speeds, especially in a method that multiplexes data from terminal equipment directly into high-speed digital rotational speeds in a bit-compatible manner. Regarding the method.

[Conventional technology]

Japanese Patent Application Laid-open No. 163741 (1982) as a method for directly multiplexing data from a terminal device into high-speed digital rotation speed
A method has been proposed in which a multiframe is constructed as shown in No. ``Multiplexing Apparatus,'' and bits of the same time slot are transmitted an appropriate number of times within the multiframe.

Figure 5 is an example of a conventional TDM signal frame and multi-frame configuration diagram, where a is a signal frame and b is a signal frame.
indicates that 20 frames constitute one multiframe.

In the signal frame a in the figure, the high-speed digital line speed is 1.536 Mb/s, so the bit length of one frame that can be used by the user is 192 bits.
1 is the bit MF for multi-frame synchronization,
No. 2 shows an example in which the service channel bit SC for service signal transmission is configured so that bit No. 3 and subsequent bits are used for data transmission.

Since the information transmission rate of 1 bit of multiframe b is 400 b/s, by using appropriate bits, low-speed data can be directly multiplexed to high-speed digital line speed and transmitted.

In conventional bit multiplexing TDM, for example, as shown in FIG. 5a, voice or data is placed on bits No. 2 to No. 195 of a signal frame and transmitted. In this example, the No. 2 bit is used as a service channel (SC) for mutual information between devices. The information transmission rate of 1 bit is 8Kb/s, so if the information transmission rate is 64Kb/s, it will be 8 bits or 32Kb/s.
In this case, 4 bits are used. For lower speeds, use multi-frame.

Since 1 bit in a multiframe is 400 b/s, 1.2 Kb/s data has the same bit number.
MFR is transmitted three times, for example, the data is assigned to No. 5 bit and transmitted using MFR Nos. 1 to 3. 2.4Kb/s
The data in the MFR of the same bit number is transmitted 6 times, for example, the data is assigned to No. 6 bit and MFR No. 1 to 6 are transmitted.
Transmit by. 9.6 Kb/s data is transmitted 24 times using 400 b/s bits in a multiframe, for example, the data is assigned to No. 7 and No. 8 bits,
MFRNo.1 to 20 (for No.7 bit) and MFRNo.
Transmitted in bits 1 to 4 (for No. 8 bit).

It is possible to allocate a mixture of high-speed data and low-speed data within one frame. For example, low-speed data can be allocated to the first half of one frame, and high-speed data can be allocated to the second half.

[Problem that the invention seeks to solve]

Conventional TDM has no restrictions on the allocation of bits in a frame to data items, and has high usage efficiency. However, on the other hand, there is no need to process data signals in units of octets within a frame, so there is no division in units of octets. Maintenance tests and line settings within the common carrier network, which is built as a basic unit, are consistent with the basic characteristics, and branching and
There were problems such as the complexity of processing required to achieve flexibility in network configurations such as relays. It was also necessary to be able to support NTT (Nippon Telegraph and Telephone Company) branching services and to be able to efficiently multiplex various types of data with different speeds.

This invention was made to solve the above problems, and it is possible to perform various line settings such as branching and relaying on an octet basis, and also to efficiently multiplex various types of data with different speeds.
The purpose is to obtain TDM.

[Means for solving problems]

The TDM according to this invention uses one to several consecutive time slots (TS...hereinafter the same) in a frame signal consisting of a plurality of time slots in units of octets.
The subframe is assigned to each route to each destination, and the subframe is bit multiplexed, and n
Construct a multiframe using subframes, configure a frame synchronization code using the bits in each subframe, configure a channel using the multiframe, and the method shall correspond to the code rate of the channel, Multiple channels are configured with the same number of bits, one channel is configured with multiple bits of different multiframe numbers, one channel is configured with multiple bits, or one channel is configured with multiple time slots. .

[Effect]

TDM in this invention is in octets.
Consecutive 1s in a frame signal consisting of multiple TSs
~ Since the subframe has several TS and is assigned to each route, various line setting processes such as branching and relaying can be performed in octet units, and it is also possible to support branching services for high-speed digital lines. The internal structure is bit multiplexed, and multi-frames are used to configure the data transmission channel, making it possible to efficiently multiplex various types of data with different speeds.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a 400 b/s system signal frame. In the figure, a indicates a signal frame on a high-speed digital line, and b indicates a multi-frame. each in a
TS is in octets. 1 frame length lTS
Among them, j to (j+k-1) consecutive kTS(k×
64Kb/s) is allocated to the route, but this indicates that in the subframe for each route consisting of this kTS, bits are handled as a series of bit strings from 1 to 8k without octet separation. . j, k, l are each integers, and when the high-speed digital rotation speed is 1.536 Mb/s (synchronization bits such as NTT are not shown) l
is 24, and the branch information to a certain direction is 192Kb/s
In this case, k=3. Further, in the case of 6.144 Mb/s, l is 96.

F in the subframe is a frame synchronization bit, which can constitute, for example, a CCTT Recommendation X.50 synchronization pattern, but this synchronization pattern may also be another code sequence. D ₁ to _{D 8k-1} are information bits that transmit data or control signals.

The multiframe shown in Fig. 1b is composed of 20 subframes, and the F bit of bit No. 1 constitutes the synchronization pattern, and bits No. 2 to No. 8k constitute the above synchronization pattern.
Multi-frame (MFR...same below) No. 1~
20 constitute a channel (CH...the same applies hereafter).

Here, Bit No. 1, A of MFR No. 1, is a path status monitoring bit, and the point that it can be used to transmit "1" when normal and "0" when abnormal is CCITT. Complies with the recommendations of

FIG. 2 shows the number of channels that can be accommodated in accordance with the data transmission speed depending on the number of identically numbered bits in a subframe in the case of the multi-frame configuration shown in FIG. 1b. The transmission speed is
This shows that multiple channels can be accommodated with the same number bit for 1.2 Kb/s, 2.4 Kb/s, etc. below 64 Kb/s.

Figure 3 is an 8Kb/s system signal frame configuration diagram.
b is the signal frame on the high-speed digital line.
The channel allocation for 8Kb/s, 16Kb/s, 32Kb/s, and 64Kb/s signal transmission is shown.

In the figure, the same symbols as in FIG. 1 indicate the same contents. I ₁ ~
_I8k represents information bits.

When the data signal transmission rate is 1.2 Kb/s and an integer multiple (q times) thereof, the accompanying control signal is
It is accommodated in a multi-frame together with a signal sampled at multiple points at 400 b/s. Figure 4: 1.2Kb/s~
An example of accommodating multiple lines of data terminals up to 19.2 Kb/s in a frame is schematically shown by speed. For 400b/s system signals, when there are m control signals, the speed is (q×1.2Kb/s+m×
400 b/s) is configured as a unit, and is sequentially accommodated in the multi-frame direction.

Now, when q=1 and m=1, the speed is 1.6 Kb/s, which requires 4 bits on a multiframe. Therefore, for 10 single lines of 1.2Kb/s data, including its control signal, bit No. 2 is used to control CH1 to CH1.
Bit No. 5 can accommodate CH6 to CH10. Similarly, if q=2 and m=1, the speed is
It is 2.5Kb/s and requires 7 bits on a multiframe. Therefore, for five 2.4Kb/s data terminal lines, bit No. 4 is used, including the control signals.
CH13 with bit No. 5 from CH11 to CH13
It accommodates a part of and CH14 to CH15.

Similarly, if q=4 and m=1, the speed is 5.2Kb/
s and requires 13 bits on a multi-frame. Therefore, for three data items of 4.8 Kb/s, bit No. 6 accommodates CH21, part of bits No. 6 and 7 accommodates CH22, and the rest of bits No. 7 accommodate CH23. Note that the channel numbers here are named according to data speed, and are not continuous from CH1. When q=8 and m=1, the speed is 10.2Kb/s, and part of bit No.8 and 9 is connected to CH31, and bit No.9 and 1
0 and accommodates CH32.

In the case of a speed of 14.4 Kb/s or 19.2 Kb/s, multiple bits on a subframe are expanded and accommodated on a multiframe. When a multi-frame is composed of subframes X20, one column of the number of channels that can be accommodated is as shown in FIG.

Although bit No. 16 and subsequent bits are not shown in the figure, it is also possible to use multi-frames in the same way, or to use multiple bits within a sub-frame as shown in Figure 3.
It is also possible to transmit high-speed data signals such as 8Kb/s, 16Kb/s, 32Kb/s, and 64Kb/s.

For example, in the multi-frame configuration shown in Figure 1b,
In No. 10, CH32 is allocated and MFR Nos. 11 to 20 are blank spaces, but data channels of other speeds can also be allocated to these blank spaces. for example
If a 2.4 Kb/s data CH is allocated, multiplexing efficiency will be improved.

Figure 4 shows the frame structure of a telephone signaling signal, with each channel being an integer multiple of 400b/s (in Figure 4, two of 400b/s and 800b/s).
(Example shown) indicates that signaling is performed by transmitting data sampled at multiple points in one bit within a multiframe.

When transmitting a signaling signal, the same multi-frame synchronization pattern as in FIG. 1 is used, but this synchronization pattern may also be of another bit string.

Data of 64 Kb/s or less, signals of 8 Kb/s, signaling signals, etc. may be mixed and multiplexed within one subframe. In addition, when branching service is not used, the multiframe synchronization bits of multiple subframes are representatively allocated within one subframe, and other subframes are processed with the same multiframe phase. It is also possible to omit the frame synchronization bit.

Note that although this embodiment has described an example in which a multiframe is made up of 20 subframes, the number of frames that make up a multiframe may be other than 20 frames. When dealing with even slower signals, set 20
More than one frame, for example 80 frames, can be made into one multiframe. When one multiframe is composed of 80 frames, the minimum multiplexing speed can be reduced to 100 bps. In addition, as a high-speed digital line, 1.536Mb/s or
I assumed 6.144Mb/s, but it turned out to be 2.048Mb/s.
It is also possible to apply to higher-order transmission speeds of 8.192 Mb/s and 32 Mb/s or higher.

〔Effect of the invention〕

As described above, according to the present invention, a channel is configured using multi-frames with consideration of divisions in octets (64 Kb/s), and in response to the code transmission speed of the channel, especially when the code transmission speed is 64 Kb/s or less. For multiple channels with the same number bit, 2
Three identically numbered bits can accommodate more than twice as many channels as one bit, and three identically numbered bits can accommodate more than three times as many channels as one bit, and one subframe can accommodate 14.4 Kb/s or 19.2 Kb/s. Kb／
It is possible to efficiently accommodate medium-speed data channels such as This makes it possible to process flexible line settings such as branching and relaying on an octet basis, and at the same time, it is possible to efficiently multiplex various types of data with different transmission speeds.

[Brief explanation of the drawing]

Figure 1 shows 400b/s according to one embodiment of this invention.
Figure 2 is a diagram showing an example of the number of channels that can be accommodated; Figure 3 is a diagram showing an 8Kb/s system signal frame configuration; Figure 4 is a diagram showing a signaling frame configuration; Figure 5 is a diagram showing a signaling frame configuration. 1 is a diagram showing a conventional TDM signal frame and multiframe structure.

Claims (1)

[Claims] One octet unit time slot (64Kb/
S unit) A subframe is configured to be allocated to different destinations by having consecutive 1 to K time slots (K is a natural number less than or equal to the total number of channels in one frame) in a frame signal consisting of multiple time slots. Bit multiplexing is performed within the frame, and a multiframe is formed from n subframes (n is any natural number), and each subframe is When configuring a channel using the above subframes or multiframes within a subframe by performing multiframe phase synchronization for each subframe, if the code transmission rate of the channel is 64 Kb/S or less, A channel is configured with one or more different multi-frame numbers with the same number bit, or with multiple different multi-frame numbers with multiple number bits, or with one number bit or multiple number bits. ,
A digital time division multiplexing system characterized by configuring a channel with multiple time slots for speeds of 64 Kb/S or higher. 2 If a channel allocation margin occurs in the same numbered time slot or same numbered bit, use it for another data channel, and prevent other channels of different speeds from coexisting within the same numbered time slot or the same numbered bit. A digital time division multiplexing system according to claim 1, characterized in that: 3 By converting m sub-signals (m is a natural number) such as control signals between terminals into n-multiframes, the minimum unit of speed given by one multi-frame number of one bit is 8/nKb/S. P times (P
is a natural number) with the main signal having a speed of (P×
8/n+mx8/n) Kb/S as one channel, and multiplexing is performed in response to a speed of 64 Kb/S or less. Digital time division multiplexing method. 4 Telephone signaling signals are separated for each telephone channel.
Claim 1 or claim 1, characterized in that the SS/SR signal is sampled at multiple points, and one or more bits in a subframe are assigned to one or more multiframe numbers for transmission. Second
The digital time division multiplexing method described in Section. 5 When configuring the above multi-frame, n=
20, and the transmission rate of one bit in one multiframe is 0.4 Kb/S.