JPH0752866B2 - Concentration distribution method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention provides a concentrating distribution system in which a plurality of terminal devices are connected to a central apparatus via concentrating distribution terminals arranged at various places. In particular, the present invention relates to a system management method capable of effectively measuring delay time in a high traffic mode.

(Prior Art) When connecting a plurality of terminal devices such as telephones to a private branch exchange (PBX) to form a network, each terminal device and the private branch exchange (PBX) must be directly wired and connected. Requires a great deal of labor, and its equipment cost is also high. That is, in most cases, these terminal devices are arranged in a plurality of floors even in a plurality of buildings or the same building. Therefore, laying a signal cable between each of these distributed terminal devices and a private branch exchange (PBX) requires a large amount of work and enormous equipment costs.

Therefore, as shown in FIG. 5, for example, the line distribution terminals 2a, 2b, to 2n are provided for each of a plurality of buildings or different floors, and the line distribution terminals 2a, 2b, to 2n are connected to the private branch exchange. The central device 1 including the (PBX) is connected via a signal cable (first transmission line 3 and second transmission line 4). Then, the terminal device 5 is installed as the concentrating distribution terminal 2 closest to the installation location.
By connecting the terminal device 5 to the concentration distribution terminal 2
It is conceivable to connect to the central device 1 via the. According to such a system configuration, not only the installation work of the signal cable between the central device 1 serving as the backbone and the plurality of concentration distribution terminals 2 is facilitated, but also the terminal device 5 is installed in the nearest concentration distribution terminal. Since it only needs to be connected to 2,
It is possible to flexibly construct a network.

Now, from the central unit 1, the transmission data for each of the concentrating distribution terminals 2a, 2b, to 2n is transmitted in a time division manner through the second transmission line 4 in a frame structure as shown in FIG. 6 (a), for example. . Here, the ASG is the central device 1 and each of the concentration distribution terminals 2a, 2b,
Concentration distribution terminal designation signal given to ~ 2n. Also, from each of the concentration distribution terminals 2a, 2b, to 2n, the transmission data for the central unit 1 is time-divided via the first transmission path 3 for uplink, for example, in the frame configuration as shown in FIG. 6 (b). Be transmitted to. Here, RSP is a response signal transmitted by the designated line concentrating / distributing terminal in response to the ASG signal for measuring a transmission delay time described later.

By the way, in such a system, signal transmission is performed between the plurality of concentration distribution terminals 2 and the central unit 1 via the common transmission lines 3 and 4 as described above. Are connected to different positions of the transmission lines 3 and 4, respectively. Therefore, the transmission line length between each concentration distribution terminal 2 and the central unit 1 is different for each concentration distribution terminal 2, and due to this difference in transmission line length, there is a difference in signal transmission delay time. Occurs. As a result, it cannot be denied that there is a difference in the signal transmission time of the signals transmitted between the respective concentration distribution terminals 2 and the central unit 1. Therefore, if the signal transmission is performed without considering the difference in the transmission delay time, there occurs a problem that the signal transmitted between each concentrator / distribution terminal 2 collides on the transmission path.

Therefore, the present inventors measured the transmission delay time in signal transmission between each concentration distribution terminal 2 and the central unit 1 in Japanese Patent Application No. 59-268824, and based on the measurement result, each concentration distribution It has been proposed that the transmission timing of the signal transmitted from the terminal 2 to the central device 1 be controlled to avoid the signal collision on the transmission path.

According to this method, basically, the central device 1 sequentially sends a line-collection / distribution terminal designating signal to a plurality of line-collection / distribution terminals 2.

Upon receiving this designation, the concentrating distribution terminal 2 transmits a predetermined response signal to the central device 1 using the window frame period, and receives the response signal returned from the central device 1.

The time from the transmission of the response signal to the reception thereof is measured as the transmission delay time between the concentration distribution terminal 2 and the central device 1.

Then, based on this transmission delay time, the transmission timing of the signal to be transmitted from the concentration distribution terminal 2 to the central unit 1 is adjusted and controlled.

However, if the traffic on the transmission line becomes high, there arises a problem that the window frame period for measuring the delay time cannot be set sufficiently. Therefore, in order to improve the use efficiency of the transmission line, the mode of delay time measurement is switched between low traffic and high traffic, and the control signal for delay time measurement is based on the delay time data measured during low traffic during high traffic. It is considered that the setting of the wind frame period is suppressed to the necessary minimum by controlling the transmission timing of the, and the delay time is measured while maintaining the high traffic state.

However, when the high traffic state continues, there is a problem that the new line concentrating / distributing terminal 2 cannot set the delay time measurement in the high traffic mode forever. Further, even when the traffic is low, it is necessary to set the window to be wide, and thus it is necessary to adjust the position of the voice time slot in use.

(Problems to be Solved by the Invention) In such a concentrating distribution method proposed hitherto, how to effectively measure the delay time when the high traffic state continues There was a problem in that.

The present invention has been made in consideration of such circumstances, and an object of the present invention is to take advantage of the above-mentioned concentrating distribution system, and even in a case where a high traffic state continues, An object of the present invention is to provide a highly practical concentrating distribution method capable of effectively measuring the delay time and improving the use efficiency of the transmission path.

[Structure of the Invention] (Means for Solving the Problems) The present invention is for transmitting information signals respectively set in first and second transmission lines provided between a plurality of concentration distribution terminals and a central device. Separately from the first and second frequency channels, a third frequency channel for transmitting control signals from the plurality of concentration distribution terminals to the central device and a control signal transmission from the central device to the plurality of concentration distribution terminals And a fourth frequency channel for the purpose of performing the rough measurement of the signal propagation delay time between the central device and the line distribution terminal via the third and fourth frequency channels, and then based on this rough measurement result. It is characterized in that the signal propagation delay time between the central equipment and the line distribution terminal via the first and second frequency channels is measured.

Further, a plurality of sets of first and second frequency channels are provided on the first and second transmission lines, and the set of first and second frequency channels is transmitted via the third and fourth frequency channels. The information is selected and designated according to the information.

(Operation) According to the present invention, the third and fourth frequency channels are used as management channels, and preprocessing such as delay time measurement of the first and second frequency channels is performed on the management channels. . Then, based on the measurement result, delay time measurement of the first and second frequency channels and transmission control thereof are performed. Therefore, even if the first and second transmission lines are in a high traffic state, the delay time is measured reliably,
It becomes possible to effectively allocate time slots and transmit information. In other words, it becomes possible to reliably measure the delay time required for information transmission while sufficiently dealing with high traffic.

Further, even if a plurality of sets of first and second frequency channels are provided, it becomes possible to effectively manage the plurality of sets of frequency channels by using the third and fourth frequency channels.

(Embodiment) An embodiment of the system of the present invention will be described below with reference to the drawings.

In this system, basically, a plurality of (n) concentrating distribution terminals (MAUs) are connected to a central device via an upstream first transmission line and a downstream second transmission line, and In a system constituted by connecting terminal devices such as telephones to the line concentrating / distributing terminals, in particular, the first set on the above-mentioned first and second transmission lines as shown in FIGS. 1 and 2. And third and fourth frequency channels are provided separately from the second frequency channel. Further, here, a plurality of sets of the first and second frequency channels are provided, and the first and second frequency channels are selectively used by information transmission using the third and fourth frequency channels. It is characterized by.

That is, as shown in the schematic configuration of this system in FIG. 1, the central unit is a modem group 11 composed of a plurality of modems having different frequency bands from each other, and a control having different frequency bands from these modems. And a modem 12 for the channel. The modems of a plurality of frequency bands accommodated in the modem group 11 are respectively connected to a plurality of sets of first and second frequency channels, and the control channel modem 12 is a third channel that constitutes a control channel. And a fourth frequency channel. It should be noted that these frequency channels are connected to a central device and a plurality of concentration distribution terminals (MA
The frequency band of the signal cable connecting to U) is set by dividing it into a plurality of bands as shown in FIG. 2, for example.
Then, the frequency band f0 is assigned to the third and fourth frequency channels as a control channel, and the n frequency bands f1, f2, to fn are assigned to the plurality of sets of the first and second frequency channels described above, respectively. , Each of which is a time division multiplexed voice data channel. Here, the frequency band f0 of the control channel is set to be narrower than the frequency bands f1, f2, to fn of the plurality of voice data channels described above.

The modem group 11 is connected to the exchange 14 via the TDMA interface 13, and the control circuit for the control channel is also used.
15 transmits information to and from a plurality of concentration distribution terminals (MAU) via the control channel modem 12, controls the TDMA interface 13, and controls each of the concentration distribution terminals (MAU). It has become a thing.

Information transmission through each of the above voice data channels is
The above-mentioned frame structure shown in FIG. 6 is used, and information transmission through the control channel is carried out using the frame structure shown in FIG.

On the other hand, the centralized distribution terminal (MAU) is a TD for connecting a telephone etc. with a modem 21 configured as shown in FIG. 4 described later.
MF interface 22, and control channel control circuit 23
And is configured.

Then, under the control of the control channel control circuit 23, after transmitting information to and from the central device via the above-mentioned control channel, the central device via the voice data channel selected and designated via this control channel. Information is transmitted between them.

The modem 21 provided in the concentrating distribution terminal (MAU) will now be described with reference to FIG. 4. Input from the telephone or the like connected to this MAU via the TDMA interface 22 and the MAU to the central unit. The data transmitted via the voice data channel or the data transmitted from the control channel control circuit 23 to the central unit via the control channel is subjected to a predetermined code conversion process by the code converter 31. , Is scrambled through the scrambler 32. Then, the scrambled transmission data is band-limited through low-pass filters (LPF) 33, 34, and then guided to mixers 35, 36 to transfer a predetermined frequency signal output from local oscillator 37 and the frequency signal. The signals, which have been phase-shifted by 90 ° through the phase shifter 38, are mixed with each other and added by the adder 39.
Are combined through the four-phase PSK modulation.

The LPFs 33, 34 receive the channel selection signal, and the band characteristics thereof are variable depending on whether the data is transmitted via the voice data channel or the control channel. By controlling the band characteristics of the LPFs 33 and 34, the frequency band f0 of the control channel is restricted so as not to unintentionally widen.

However, as described above, the 4-phase PSK-modulated signal passes through the bandpass filter (BPF) 40 of a predetermined band, is guided to the mixer 41, and uses the signal of the predetermined frequency oscillated and output by the frequency synthesizer 42. Is modulated. Under the control of the control channel control circuit 23, the frequency synthesizer 42 receives control data designating one of the plurality of frequency channels (a plurality of voice data channels or control channels) and controls the frequency band of the frequency band. It oscillates a signal. The transmission frequency band of the 4-phase PSK-modulated signal is determined by the designated control of the oscillation frequency of the frequency synthesizer 42. Then, this signal is sent out to the above-mentioned transmission line via the BPF 43 and is transmitted to the central device.

On the other hand, the signal received from the central unit via the transmission line is
Ingested via BPF44. Here, the signal sent from the central unit via the control channel is further taken into the demodulator 46 via the BPF 45 and demodulated. The signal received via this control channel is
It may be a 4-phase PSK modulation signal or an FSK signal. The signals received and demodulated in this way are managed and
It is given to the control channel control circuit 23 as control data.

On the other hand, the signal of the voice data channel taken in through the BPF 44 is guided to the mixer 47, mixed with the signal oscillated by the frequency synthesizer 42, and demodulated.
Thereafter, the 4-phase PSK modulated signal which is the demodulated signal is guided to the 4-phase PSK demodulator 49 via the BPF 48 and the received data is reproduced. The received reproduction data is output to the telephone set or the like connected to the MAU via the TDMA interface 22.

The clock regeneration circuit 50 regenerates the reception clock from the outputs of the demodulators 46 and 49, and receives the channel selection signal and regenerates the clock from the output signal of the demodulator 46 when the control channel signal is received. At the time of receiving the signal of the voice data channel, the clock is reproduced from the output signal of the demodulator 49.

In the present system configured as described above, the control channels (third and fourth frequency channels) provided separately from the above-mentioned plurality of voice data channels (a plurality of first and second transmission paths) are as follows. It is used as follows.

That is, the signal format of information transmitted through this control channel is configured as shown in FIG. 3, and information is transmitted between the central unit and a plurality of centralized distribution terminals (MAU) through this channel. It is used for transmitting various control information and management information for communication. And MA
If U newly enters by turning on the power, etc., M
Initial measurement of the propagation delay time in the transmission line is performed between the AU and the central unit via this control channel.

However, at the time of initial measurement of the propagation delay time, it is unknown at which position on the transmission line the MAU is connected. Therefore, as described above, it is necessary to set a long window period for measuring the delay time. Since the control channel does not always have a high traffic state unlike the voice data channel, the window period is set by using the spare area for transmitting the system management information and the like. ing.

However, this control channel has a different frequency band from the above-mentioned multiple voice data channels, and the frequency band itself is set narrower than the voice data channel, so measurement is performed via the control channel. It is undeniable that the propagation delay time caused is slightly different from the propagation delay time when actually transmitting a signal through the voice data channel.

Therefore, in this system, when a MAU newly enters, the propagation time with the central unit is first measured via the control channel, and at the same time, which channel among the plurality of voice data channels described above is measured via this control channel. Is used to selectively specify whether to transmit data to and from the central device. This selection designation is controlled by, for example, monitoring the traffic states of a plurality of voice data channels.

Then, using the selected voice data channel,
First, the signal transmission timing is controlled based on the propagation delay time measured via the control channel as described above, and the propagation time is measured with the central device.

In other words, using the control channel to measure the propagation time roughly,
According to this rough measurement result, the propagation delay time in the voice data channel selected and designated is measured with high accuracy.

Then, a time slot is assigned from the central unit in the selected and designated voice data channel, and between the central unit and the central unit under the signal transmission timing control based on the delay time measurement result via the designated time slot. It is supposed to transmit information.

Thus, in this system, even when the voice data channel (first and second frequency channels) is in a high traffic state, it is possible to reliably measure the delay time for the MAU newly entering the market. In other words, it is possible to roughly measure the propagation delay time via a low-traffic control channel and control the transmission timing of the control signal for measuring the delay time in the voice data channel based on the rough measurement result. The delay time can be measured in the high traffic mode while keeping the channel in the high traffic state.

That is, since a plurality of voice data channels are set by frequency division of the transmission path band and information is transmitted while using each of them in time division, the traffic volume can be greatly increased. After that, coarse measurement of the delay time through the control channel and allocation of the voice data channel are performed, and the delay time is measured in the designated voice data channel based on the rough measurement result.・ It becomes possible to effectively measure the delay time for newly entered MAUs while maintaining high traffic for each channel.

According to the above-mentioned control channel in this system, the following actions are also exhibited.

That is, as described above, when a plurality of transmission lines are set between the central device and a plurality of concentrated distribution terminals (MAU),
It is possible to distribute the traffic volume of each voice data channel by monitoring the traffic state of those transmission lines and selecting the voice data channel by information transmission via the control channel according to the monitoring result and assigning it to multiple MAUs. it can. Therefore, even if the calls from the centralized distribution terminals (MAUs) are concentrated, it is possible to cope with this.

Normally, each concentrating distribution terminal (MAU) has a long global address of about 64 bits, but in general, when transmitting information only within a certain system, for example, a short local address of about 16 bits is used. It is often preferable to specify the centralized distribution terminal (MAU).

Therefore, for such a request, for example, by assigning a local address to the concentrating distribution terminal (MAU) in the system via the control channel, the information is transmitted at the time of information transmission via the voice data channel. local·
The address can be effectively used. As a result, it is possible to realize effective information communication without using the long global address described above each time.

Especially when the local systems are connected to each other nationwide to construct a large-scale system, the above-mentioned local address has a great effect.

The present invention is not limited to the above embodiment. Although the case where a plurality of sets of first and second transmission lines are used as a plurality of frequency-multiplexed voice data channels has been described here, needless to say, one voice data channel may be used. Also, the number of time slots set in the voice data channel may be determined according to the specifications. Further, the frequency band of the voice data channel and the frequency band of the control channel may be determined according to the transmission line characteristics. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

EFFECTS OF THE INVENTION As described above, according to the present invention, first and second frequency channels for information signal transmission are provided on the first and second transmission lines between the central device and the plurality of concentration distribution terminals. Separately provided third and fourth frequency channels for control signal transmission,
After performing a rough measurement of the propagation delay time via the third and fourth frequency channels, a first measurement is performed according to the rough measurement result.
Also, the propagation delay time in the second frequency channel is measured. Therefore, according to the present invention, it is possible to obtain a great practical effect such as enabling a new entry of a concentrating distribution terminal while keeping the first and second frequency channels in a high traffic state.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a communication system to which a concentration distribution system according to an embodiment of the present invention is applied, FIG. 2 is a diagram showing a relationship between a voice data channel and a control channel, and FIG. 3 is a control channel. FIG. 4 is a diagram showing an example of a format of a signal transmitted via the present invention, FIG. 4 is a diagram showing a configuration example of a modem provided in a concentration distribution terminal according to the present invention, FIG. 5 is a diagram showing a basic concept of a concentration distribution system, FIG. FIG. 6 is a diagram showing an example of a basic format of a signal transmitted between the central device and the concentration distribution terminal. 1 ... Central device, 2a, 2b, ... 2n ... Concentration distribution terminal (MA
U), 3 ... first transmission line, 4 ... second transmission line, 11 ...
... modem group, 12 ... control channel modem, 21 ... modem, 23 ... control channel control circuit, f0 ... control channel (third and fourth frequency channels), f1, f2, ... fn ...
Voice data channel (sets of first and second frequency channels).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Saito 1-3-3 Uchisaiwai-cho, Chiyoda-ku, Tokyo Within Tokyo Electric Power Company (72) Hidero Haruyama 1 Komukai-Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Incorporated company Toshiba Research Institute (72) Inventor Kazuyoshi Ozawa 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research Institute (72) Inventor Hiroshi Kobayashi Komukai-Toshiba, Kawasaki-shi, Kanagawa No. 1 Incorporated company Toshiba Research Institute (56) References JP-A-61-145995 (JP, A) JP-A-62-26947 (JP, A)

Claims (4)

[Claims] 1. An information signal is time-divisionally transmitted from a plurality of concentration distribution terminals to a central device via a first frequency channel on a first transmission line, and a second signal is transmitted on a second transmission line.
In a concentrating distribution method for transmitting information signals in a time division manner from the central device to the plurality of concentrating / distributing terminals via the frequency channels, the first concentrating device is provided between the plurality of concentrating distribution terminals and the central device.
In addition to the second frequency channel, a third frequency channel for transmitting a control signal from the plurality of concentration distribution terminals to the central device is provided on the first transmission path, and A fourth frequency channel for transmitting a control signal to the line concentrating / distributing terminal is provided on the second transmission line, and signal transmission is performed using the third and fourth frequency channels, First measuring means for roughly measuring the signal propagation delay time between the plurality of concentration distribution terminals, and setting signal transmission timing based on the rough measurement result obtained by the first measuring means, When signal transmission is performed using the first and second frequency channels according to the set transmission timing, and a signal propagation delay occurs between the central device and the plurality of concentration distribution terminals. The first to the accuracy measurement 2
Concentration distribution system characterized by comprising: 2. A plurality of sets of first and second frequency channels are provided, which are selectively designated by information transmitted through the third and fourth frequency channels. The concentrating distribution method described in item 1. 3. The concentrating distribution system according to claim 1, wherein the first to fourth frequency channels are set by frequency division. 4. The third and fourth frequency channels and the plurality of sets of first and second frequency channels are set by dividing a frequency band, and the plurality of sets of first and second frequencies are set. The concentrating distribution system according to claim 1, wherein the frequency bands of the third and fourth frequency channels are set narrower than the channels.