JPS63157537A - Method for time division multiplex transmission and device therefor - Google Patents

Abstract

PURPOSE:To efficiently use a transmission line by adaptively multiplexing a channel in which a significant signal exists among plural channels different in bit rate. CONSTITUTION:A time division multiplex transmitter has a first multiplexing circuit 110, a channel memory circuit 120, a second multiplexing circuit 130 and a time slot control circuit 140. The first multiplexing circuit 110 multiplexes plural input channels and the channel memory circuit 120 writes and reads a multiplex channel signal outputted from the first multiplexing circuit 110 in accordance with an output from an assignment information memory in the time slot control circuit 140. The second multiplexing circuit 130 multiplexes the output from the first multiplexing circuit 110 through the channel memory circuit 120 and the multiplexing information from the time slot control circuit 140. The time slot control circuit 140 outputs multiplexing information for updating and shifting the multiplexed channels in a transmission frame to the 2nd multiplexing circuit 130.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a time division multiplex transmission method and device thereof, and more specifically, it relates to a time division multiplex transmission method and an apparatus thereof, and more specifically, to accommodate multiple channels having different bit rates at once and transmit high-speed transmission. The present invention relates to a time-division multiplexing method and device that enables efficient (flexible) multiplexing using digital dedicated lines and the like.

[Conventional technology]

Conventionally, when transmitting a plurality of channels by time division multiplexing, the bit rate of each channel was almost always the same. For example, a PC that multiplexes 24 channels of audio lines using a 1.544 Mbps digital line.
In M24 line transmission equipment, all channel bit rates are 6
It is 4 kbps. Furthermore, even when multiplexing channels with different bit rates, each channel is often multiplexed in a fixed or semi-fixed manner (although if the number of input channels or bit rate changes, etc. It was necessary to temporarily stop system operation and make changes to the system.

[Problem that the invention seeks to solve]

However, in recent years, due to the development of audio encoding technology and the accompanying diversification of services, different bit rates have come to be used for each channel depending on the service and transmission quality. There is a need for something that can flexibly respond to rate changes, input channel configuration changes, and even traffic fluctuations without causing momentary communication interruptions, and conventional technology cannot meet these demands. .

In view of the drawbacks of the prior art, an object of the present invention is to be able to efficiently multiplex a plurality of input channels with different bit rates, and also to be able to cope with changes in bit rate and input channel configuration, as well as traffic fluctuations. It is an object of the present invention to provide a highly efficient and flexible time division multiplex transmission method and apparatus that can be flexibly adapted.

[Means for solving problems]

The time division multiplex transmission method of the present invention is a time division multiplex transmission method in which a plurality of input channels having different bit rates are time division multiplexed and transmitted, and among the input channels, an active channel in which a significant signal exists is selected. Input channels with the same bit rate are grouped and multiplexed within a transmission path frame, giving priority to inactive channels, and when a new active channel occurs among unmultiplexed inactive channels, the At least one inactive channel is selected according to a predetermined priority from among the input channels of other bit rates that are multiplexed within the group in which the input channel of the bit rate is multiplexed or that is multiplexed before or after the group. to select and multiplex the new active channel in place of this inactive channel, and to respond to the occurrence of a new active channel when a new active channel does not occur. moving the inactive channels within the group so as to place a number of inactive channels in a predetermined position, and transmitting the multiplexed input channel and multiplexing information indicating the change or movement of the multiplexed input channel. It is characterized by

Further, the time division multiplex transmission device of the present invention includes a first multiplexing circuit that multiplexes a plurality of input channels, and a channel state signal that stores a channel state signal indicating the presence or absence of a significant signal in the plurality of input channels and its bit rate. a channel state memory; an allocation information memory that stores channel allocation information indicating which channel among the plurality of input channels is multiplexed on a transmission path; and a multiplexed information memory output from the first multiplexing circuit. a channel memory circuit for writing and reading channel signals according to the output of the allocation information memory; and a detection means for detecting a new active channel in which a new significant signal has been generated based on the outputs of the allocation information memory and the channel state memory. , From the allocation information from the allocation information memory, a predetermined number of inactive channels in which no significant signal exists among the channels grouped by bit rate in the transmission line frame are assigned to the beginning and/or end of the group. determining means for determining whether or not the multiplexed channels are multiplexed in the transmission path frame; The present invention is characterized by comprising: time slot allocation means for outputting to an information memory; and a second multiplexing circuit for multiplexing the output of the first multiplexing circuit and the multiplexed information.

[Effect]

Normally, voice signals, data signals, and image signals are not always present in telephone lines, data lines, and image lines.
For example, it is statistically known that on voice lines, voice signals actually exist only about 40% of the time, and on data lines and image lines, the time when meaningful information is actually being sent varies widely. That's about it. Focusing on this point, transmission paths can be effectively utilized by giving priority to channels in which significant signals exist among a plurality of input channels, time-division multiplexing, and transmitting the signals. For example, if this principle is applied to a transmission path that conventionally multiplexed 48 audio channels, it is possible to transmit about 100 audio channels using the same transmission path. The present invention utilizes the above-mentioned principle by accommodating various channels with different bit rates all at once.The channels are grouped by bit rate and multiplexed within a transmission line frame, and between each group, intra-frame By exchanging the time slots with each other, the entire group can efficiently utilize the transmission path time slots to improve transmission efficiency. In other words, when time slots in a transmission path frame are fixedly assigned for each bit rate and channels with significant signals (active channels) are preferentially multiplexed using only those time slots, active When there is a shortage of time slots due to an increase in the number of channels, that time slot cannot be used even if there is an unused time slot for another bit rate. Channels for transmission can be grouped, and the number of time slots assigned to each group can be made variable depending on the traffic. Specifically, an inactive channel sufficient to accommodate at least one channel of the adjacent group is arranged at the boundary of each group, and when there is a shortage of time slots for the adjacent group, the time slot for this inactive channel is allocated. By immediately supplying the data to adjacent groups, it is possible to mutually compensate for the lack of time slots between each group, making it possible to use the transmission path effectively over the entire input channel.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

Figures 1 to 4 show one embodiment of the present invention.
The figure is a block diagram of a time division multiplex transmitter, and FIG. 2 shows the configuration of its time slot (TS) management circuit.

As shown in FIG. 1, the time division multiplex transmitter includes a first multiplexing circuit (MUX 1) 110, a channel memory circuit 120, a second multiplexing circuit (MUX2) 130, and a time slot (TS ) has a management circuit 140.

The first multiplexing circuit 110 is a circuit that multiplexes a plurality of input channels. The channel memory circuit 120 is a memory circuit that writes or reads the multichannel signal output from the first multiplexing circuit 110 in accordance with the output of an allocation information memory, which will be described later, in the time slot management circuit 140. The multiplexing circuit 130 connects the first multiplexing circuit 1 via this channel memory circuit 120.
This is a circuit that multiplexes the output of 10 and multiplexed information, which will be described later.

The time slot management circuit 140, as shown in FIG.
Channel state memory 200 and allocation information memory 210
and a new active channel (ACH) detection circuit 22
0, a time slot (TS) allocation circuit 230, and a group condition determination circuit 240.

The channel state memory 200 is a memory that stores channel state signals indicating the presence or absence of significant signals of a plurality of input channels and their bit rates, and the allocation information memory 21
0 is a memory that stores channel allocation information indicating which channel is multiplexed on the transmission path among the plurality of input channels, and this allocation information memory 210
The output of is applied to the channel memory circuit 120 shown in FIG.

The new active channel detection circuit 220 is a circuit that detects a new active channel in which a new significant signal has been generated based on the output signals of the allocation information memory 210 and the channel state memory 200. Group condition determination circuit 24
0 indicates that, from the allocation information output from the allocation information memory 210, a predetermined number of inactive channels in which no significant signal exists among the channels grouped by bit rate in the transmission line frame are at the beginning of the group. , and the time slot allocation circuit 230 is a circuit for determining whether or not the time slot allocation circuit 230 is multiplexed at the end.
20 and the output of the group condition determination circuit 240, this circuit outputs multiplexing information for updating and moving multiplex channels within the transmission path frame, and this multiplexing information is output to the allocation information memory 210. together with the first
It is adapted to be added to the second multiplexing circuit 130 shown in the figure.

When transmitting by a transmitting device having such a configuration, when multiple input channels with different bit rates are time-division multiplexed and transmitted, the input channel (active channel) where a significant signal exists among the input channels is Input channels with the same bit rate are grouped and multiplexed within a transmission path frame, giving priority to input channels that are not multiplexed (inactive channels), and when a new active channel occurs among unmultiplexed inactive channels, this new At least one of the input channels of other bit rates that are multiplexed in the group in which the input channels of the same bit rate as the active channel are multiplexed, or immediately before or after this group according to a predetermined priority order. Selects an inactive channel of a channel and multiplexes a new active channel in place of the inactive channel, and if no new active channel occurs, a predetermined number of channels are added at the beginning and end of each group in the frame. This is done by moving an inactive channel within a group in order to arrange the inactive channel, and thus transmitting the multiplexed input channel and multiplexing information indicating the change or movement of the multiplexed input channel. .

Further, the time division multiplex transmission method of this embodiment will be explained with reference to FIGS. 3 and 4.

N-channel signals from CHI to CHN, indicated by reference numeral 100, are input to a first multiplexing circuit (MUXI) 110, multiplexed, and then input to a memory circuit 120 via a signal line 111. The memory circuit 120 writes only the signals of the channels to which the transmission line time slots are assigned among the input channels in response to the control signal input from the time slot (TS) management circuit 140 via the signal line 141, This is read out via the signal line 121 and output to the second multiplexing circuit (MUX2) 130. Channel information indicating the bit rate and significant signal of each input channel is input to the (TS) management circuit 140 via the signal line 150, and based on this channel information, the time slot in the transmission path frame is assigned a significant signal. Priority is given to channels that have existing channels. Regarding this time slot assignment, multiplexing information for notifying the receiving side of changes in the multiplexing channel etc. is output via the signal line 142, and this information is sent to the second multiplexing circuit (MUX2). At 130, it is multiplexed with the multiplexed channel signal input via signal 1121 and output via signal line 131. Further, the TS management circuit 140 outputs a signal to each channel via the signal line 143, which indicates whether or not a transmission path time slot is assigned to the manual channel. Each channel unit or module uses this assignment information to know whether or not its own channel is multiplexed, and if it is not multiplexed, it can, for example, temporarily store transmission data in a buffer and assign a time slot. Deterioration of encoding quality can be prevented by making the audio encoder wait, or by stopping the operation of the audio encoder in synchronization with the decoder so that the internal state remains the same for both transmission and reception.

In FIG. 2, which is an embodiment of the TS management circuit 140 in FIG. 1, channel information input via the signal line 150 is stored in the channel state memory 200 and then
A new active channel (
ACH) is input to the detection circuit 220. The channel information indicates the presence or absence of a significant signal in the input channel and its bit rate, and information from channel 1 to channel N is multiplexed in a time-division manner. On the other hand, the assignment information informs whether or not each input channel is currently multiplexed on a transmission path in order of channel number, similar to the channel information. Based on this information, the new active channel (ACH) detection circuit 220 detects a so-called new active channel in which a significant signal is generated among channels that are not currently multiplexed, and assigns the channel number and bit rate to the time slot) ( TS) Assignment circuit 23
0 to request time slot allocation. The group condition determination circuit 240 uses the above-mentioned allocation information as input to check how transmission path time slots are allocated to the input channels, groups the input channels by bit rate, and identifies the beginning and end of each group. It is determined whether or not a predetermined number of inactive channels have been arranged, and if not, it is determined via the signal line 241 in which group and in which position the inactive channels should be arranged. The TS allocation circuit 230 is notified. The TS allocation circuit 230 checks what kind of multiplexing is currently being performed from the allocation information output from the allocation information memory 210, and assigns a new AC).
Based on a new connection request and a request to move an inactive channel to the group end from the I detection circuit 220 and group condition determination circuit 240, the currently used transmission path time slot is assigned to a new active channel, and the existing multiplexed channel is Decide on changes to the position within the frame, etc.
The result is sent to the allocation information memory 21 via the signal line 231.
0 to update the time slot allocation information, and also to send the same information to the receiving side.
The second multiplexing circuit (MUX2) in FIG.
The allocation result is also output to 130.

FIGS. 3 and 4 are flowcharts and transmission path frame formats for explaining the operation of the TS allocation circuit 230 in more detail. Each step (31~
38) will be explained. In step S1, data is read from the outside. This data includes the allocation information from the allocation information memory 210 mentioned above and the new AC
These are time slot allocation requests and group condition determination results output from the H detection circuit 220 and the group condition determination circuit 240. In step S2, the time slot allocation requests among these are checked, and if any of the previously unconnected channels has generated a significant signal and become active, the process advances to step S3; otherwise, , the process moves to step S4. In step S3, it is checked whether or not there is an empty time slot among the time slots in the current transmission line frame for the channel for which the new allocation request is made. Here, this empty time slot will be explained using an example of the transmission path frame format shown in FIG. In the example shown in Figure 4, there are N types of bit rates (
Bl, B2. . . BN) are grouped into groups (Gl, G2 . . . BN) in each frame.
...GN). In this configuration, the lowest speed (B
The channels of 1) are multiplexed and transmitted using one time slot (TS) per channel, and the channels of 2. Third group G2. Assuming that channels with bit rates (B2.B3) that are twice and four times higher than those in G1 are grouped and multiplexed in G3, G2.
G3 requires 2TS and ATS per channel, respectively. Note that A and I in the frame mean an active channel and an inactive channel, respectively. Further, AM in the frame indicates an assignment message for notifying the receiving side of a time slot allocation change, and f is a bit for frame synchronization. Well, now -
As an example, assuming that the bit rate of the channel for which a new time slot allocation request was made in step S3 of FIG. This is possible if there is at least one inactive channel,
Even when there is no inactive channel in group G2, if there is an inactive channel that can accommodate one channel with bit rate B2 at the right end and left end of adjacent groups Gl and G3, this is used to slot the time slot. It is possible to allocate

Therefore, if there are two ■ channels at the right end of group G1 or one I channel at the left end of group G3, they can be assigned even if there is no I channel in group G2. New allocation information is created in step S5. However, G
2. Right end of Gl.

Inactive channels other than the left end of G3 are not allocated, and groups for each bit rate are not broken. When doing this, it prevents multiple time slots from being assigned to a channel at random, simplifies overall control, and
Because you can secure multiple consecutive time slots,
The time required for time slot assignment and the length of an assignment message for sending assignment information to the receiving side can be reduced.

In this way, multiple input channels C with different bit rates
In a time division multiplex transmission method in which HI to CHN are time division multiplexed and transmitted, an input channel (active channel) in which a significant signal exists on input channel C 1 to CHNO is divided into an input channel (inactive channel) that does not have a significant signal.
Input channels with the same bit rate are grouped and multiplexed within a transmission path frame, giving priority to input channels with the same bit rate ( In the present example, the input channel B2) is predetermined from among the input channels of other bit rates that are multiplexed within the group being multiplexed (G2 in the present example) or immediately before or after this group. At least one inactive channel is selected according to the assigned priority order, and a new active channel is multiplexed in place of this inactive channel.

In this way, each group expands its own group by invading the I-channel at the edge of the adjacent group when there is no I-channel within its own group, i.e. when traffic becomes busy. Group boundaries automatically move according to traffic, and time slots can be used effectively as a whole. In order for the boundaries of each group to move smoothly according to traffic, the fourth
Gl, G2. As shown in G3, channels for boundary movement may be always arranged at both ends of each group so that time slots can be exchanged immediately with adjacent groups. For this purpose, it is determined in step S4 in FIG. 3 whether there are at least as many I channels as the number of time slots for one channel of the adjacent group at the end of each group. If there is a shortage of ■channels at the end of the group in step S4, in step S6
Move the required number of channels to the end of the group.

In this way, the inactive channels within the group are moved so that a predetermined number of inactive channels are placed at the beginning and end of the group in each group within the frame, and in step S6 of FIG. (2) Allocation change information for moving a predetermined number of channels to the end of the group is created. If there is no new allocation request or insufficient group end conditions, refresh (REFRESH) information is created in step S7. This refresh information is transmitted and received by transmitting the multiplexing status within the frame (which channel is multiplexed to which time slot) to the receiving side when there is no change in the multichannel configuration within the frame. This is to match the multiplexing status at the time, and it plays the role of error correction when an incorrect assignment message (AM) is sent to the receiving side due to a transmission line bit error before that time. In step S8, step 35
．． Each piece of information generated in step 36 or S7 is output as allocation information.

Time slot (TS) allocation circuit 23 shown in FIG.
0, such processing is performed, and its output is given to the second multiplexing circuit 130 shown in FIG.
In this way, the multiplexed input channels and multiplexing information indicating change or movement of the multiplexed input channels are transmitted.

FIG. 5 shows an embodiment of a receiving device corresponding to the time division multiplex transmitting device according to the present invention, and FIG. 6 shows the configuration of its time slot (TS) management circuit.

This receiving device multiplexes an input channel in which a significant signal exists among a plurality of input channels with different bit rates over an input channel that does not, and transmits the multiplexed information together with the second input channel on the transmitting device side. A first demultiplexing circuit 510 receives the multiplexed signal from the multiplexing circuit 130 and separates the multiplexed input channel and multiplexed information from the multiplexed signal; Assignment to decode multiplexed information as input (
AM) A signal decoding circuit 610 and an allocation information memory 6 that updates the contents of the memory according to the output of the decoding circuit 610.
00, and a memory circuit 5 that changes the multiplexing order of the multiplexed input channel signals output from the first separation circuit 510 in accordance with the output of the allocation information memory 17600 and outputs the multiplexed input channel signals.
20, and a second separation circuit 540 that separates the output of this memory circuit 520 into output channels corresponding to the input channels.
It has

As shown in FIG. 5, a received signal input via a signal line 500 is separated into an assignment message and a multichannel signal by a first separation circuit (DEMUX1) 510, and the received signal is input via signal lines 511 and 512, respectively. and is input to the memory circuit 520 and the TS management circuit 530. In the memory circuit 520, multi-channel signals that are randomly multiplexed and input with respect to channel numbers are rearranged in order of channel numbers according to assignment information input from the TS management circuit 530 via a signal line 531, and are then sent via a signal line 521. Output. Second separation circuit (DUMU
In X2) 540, each channel signal is separated and output to each channel via a signal line group 550. The TS management circuit 530 learns the channel configuration in the multiplexed signal sent from the transmitting side based on the assignment information input via the signal line 521, and outputs the assignment information to the aforementioned memory circuit 520. , outputs information indicating whether or not the signals of each channel are currently multiplexed via the signal line 532. Based on this information, each channel unit or module sends a synchronization flag bit to the receiving terminal when it is not multiplexed in the case of a data line, or operates a decoder in the case of an audio line. By stopping the encoder in synchronization with the encoder on the transmitting side, control is performed such that the internal state of transmission and reception remains the same and quality deterioration does not occur during remultiplexing. In FIG. 6, which is an embodiment of the TS management circuit 530 in FIG. What kind of change has occurred in the configuration of the channel group multiplexed within the channel group is decoded, and a signal for updating the allocation information memory 600 accordingly is outputted via the signal line 611.

A map is created in the allocation information memory 600 that shows which channel is multiplexed into which time slot in the currently transmitted frame, and is updated sequentially by the signal from the AM signal decoding circuit 610 mentioned above. , the same map as that on the transmitting side is created, and control signals are outputted to the aforementioned memory circuit 520, each channel unit, etc. via signal lines 531 and 532 based on this map.

Note that each of the embodiments described above may be performed by software control instead of hardware, and in particular, T
The S management circuit may be implemented by a commercially available microprocessor.

Further, although the embodiment does not specifically limit signals sent through multiple channels, it is obvious that the present invention is effective even when a single medium such as voice, data, and images or various types of media are mixed. be.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to efficiently adaptively multiplex channels in which significant signals exist among a plurality of channels with different bit rates, and this makes it possible to efficiently utilize transmission lines. Extremely effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram of an example of the time slot (TS) management circuit of FIG. 1, FIG. 3 is a flowchart showing an example of the processing contents, FIG. 4 is a diagram showing an example of a transmission line frame format, FIG. 5 is a block diagram showing an example of a receiving device for receiving transmission information according to the present invention, and FIG. 6 is a diagram showing an example of the time slot (TS) management circuit of FIG. It is a block diagram of an example. 100...Input channel group 110...First multiplexing circuit (MUXI) 120
...Channel memory circuit 130 ...Second multiplexing circuit (MUX2) 140
...Time slot (TS) management circuit 200
... Channel state memory 210 ... Allocation information memory 220 ... New active channel (ACH) detection circuit 230 ... Time slot (TS) allocation circuit 2
40...Group condition determination circuit 510...First separation circuit (DEMUXI) 52
0...Memory circuit

Claims (3)

[Claims] (1) A time division multiplex transmission method that time division multiplexes and transmits a plurality of input channels with different bit rates, wherein active channels in which significant signals exist are given priority over inactive channels among the input channels. Input channels with the same bit rate are grouped and multiplexed within a transmission path frame, and when a new active channel occurs among unmultiplexed inactive channels, the input channels with the same bit rate as this new active channel are multiplexed. At least one inactive channel is selected according to a predetermined priority from input channels of other bit rates that are multiplexed within a group that has been set up, or is multiplexed before or after that group. The new active channel is multiplexed instead of the new active channel, and a predetermined number of inactive channels are set in a group within the frame so as to be able to cope with the occurrence of a new active channel when a new active channel does not occur. moving an inactive channel within a group to a position; and transmitting the multiplexed input channel and multiplexing information indicating a change or movement of the multiplexed input channel. Multiplexing method. (2) In the time division multiplexing transmission method according to claim 1, when the new active channel occurs, the selection of the inactive channel from among the input channels of other bit rates is based on the newly generated active channel. This is done from among the input channels of other bit rates that are multiplexed immediately before or after the group in which the input channels of the same bit rate as the channel are multiplexed, and the inactive channel when no new active channel occurs. A time division multiplex transmission method characterized in that the movement is performed to place an inactive channel at the beginning and/or end of each group. (3) a first multiplexing circuit that multiplexes a plurality of input channels; a channel state memory that stores a channel state signal indicating the presence or absence of a significant signal in the plurality of input channels and its bit rate; and the plurality of input channels. an allocation information memory that stores channel allocation information indicating which of the channels is multiplexed on a transmission path; and an output of the allocation information memory that outputs the multichannel signal output from the first multiplexing circuit. a channel memory circuit for writing and reading according to the allocation information memory; a detection means for detecting a new active channel in which a new significant signal is generated based on the outputs of the allocation information memory and the channel state memory; and allocation information from the allocation information memory. From this, it is determined whether a predetermined number of inactive channels in which no significant signals exist are multiplexed at the beginning and/or end of the group among the channels grouped by bit rate in the transmission path frame. a determining means for making a determination; and a time slot allocating means for outputting multiplexing information for updating and moving multiple channels within a transmission line frame to the assignment information memory based on the outputs of the assignment information memory, the detection means, and the determination means. and a second multiplexing circuit that multiplexes the output of the first multiplexing circuit and the multiplexed information.