JPS60103747A - Time division multiplex communication equipment - Google Patents

Abstract

PURPOSE:To prevent data leakage to other stations than a corresponding transmission/reception station by transmitting a burst data signal while applying time series position conversion and multiplexing at a mult-frame period according to a prescribed rule on a time series. CONSTITUTION:A data signal of transmission stations 30a-30c is converted into a burst data signal respectively by transmission interface circuits 301a-301c and inputted respectively to time series position converting circuits 302a-302c. The circuits 302a-302c apply position converting at each frame unit at each multi- frame period to a burst data signal of each transmission station on time series so as not to produce collision, and the result is transmitted by a multiplexing circuit 303 through time division multiplex. Channel selection circuits 304a-304c select a signal from the reception signal in the unit of corresponding frame in response to the time series on the reception station and the burst signal corresponding to the own station is separated. Moreover, time series position inverters 305a-305c rearrange the signal into the burst data signal of a prescribed channel and it is demodulated into the original continuous signal by frequency converting circuits 306a-306c.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a time division multiplex communication device, and more particularly to a time division multiplex communication device having a simple secret circuit function for preventing leakage of data signals.

[Prior art]

As a time-division multiplex communication device, for example, the transmitting side time-division multiplexes the data signals of N stations (N is an integer such that N>1) and transmits them, and the receiving side transmits the output data signals of the N stations, respectively. A multidirectional multiplex communication system is an example of a communication system that extracts only the data signal corresponding to its own station from among the data signals. That is, in such a multidirectional multiplex communication system, one base station (i.e., master station) and a plurality of subscriber stations (i.e., slave stations) communicate with each other.

The master station transmits time division multiplexed (TDM) signals to each slave station, and each slave station extracts only its own signal. However, this communication system has a problem in that the receiving station can pick up signals from stations other than its own station.

This will be explained below using FIGS. 1 and 2.

FIG. 1 is a schematic diagram of a conventional time division multiplex communication device, and FIG. 2 shows the timing of burst data signals in each part of FIG. 1.

Now, a case where data signals are transmitted from transmitting station] Oa to receiving station 14a, from transmitting station Job to receiving station 14b, and from transmitting station 10c to receiving station 14c.

The data signals transmitted from each transmitting station are different.

Transmission interface circuits 101a, 101b, 101c
It is placed on a time-series channel with a predetermined constant period. For example, the data signal of the transmitting station 10a is transmitted to channel CHI of FIG.
The data signal of b is shown in FIG.
The data signal of station 105 is channel CH in FIG. 2(c).
3, respectively, and are sent out as gust-like data signals. The data signals of each transmitting station, which are converted into burst data signals of different channels having a constant period in time series, are multiplexed by the multiplexing circuit 102 and sent out as shown in FIG. 2(d).

At the receiving station, channel selection circuits 103a and 103b select the multiplexed signal sent from the transmitting side.

103C, one frequency conversion circuit 104a, 104b selects the first-wave data signal corresponding to its own station at a constant cycle and separates each signal.

]04c, the same signal as the data signal on the transmitter side is reproduced on both channels. First, in the receiving station 14a, the channel selection circuit 103a selects the burst data signal of channel CHI shown in FIG. 2(a).

Furthermore, the frequency conversion circuit 104a converts the frequency of the burst data signal of channel CHI and extracts it as the original continuous data signal. Do the same.

The receiving stations 14b and 14c also take out the original data signals.

In the above system 2, e.g. from station 10a to station 14a
If the channel selection circuit 103b of the second station 14b selects channel CHI while transmitting a data signal to the second station 14b, even one station 14b can receive the data signal from the station 10a. This also applies to other receiving stations, and depending on the settings of the channel selection circuit), it is possible to receive signals even if they are on other channels. There is a risk that data signals between the transmitting and receiving stations t, b, , s may leak to other stations.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a time division multiplex communication device having a function of preventing data signal contents from leaking to receiving stations other than those between corresponding transmitting and receiving stations.

[Structure of the invention]

The present invention provides a one-time division multiplex communication device in which, on the transmitting side, the output of the transmitting interface circuit, the first-order data signal, is time-series in a multi-frame period according to a predetermined rule so that each station will not cause a collision in one time series. Series position conversion is performed, and the /N+N north totaler signals of each transmitting station are multiplexed and sent out by a multiplexing circuit. On the other hand, on the receiving side, a channel selection circuit selects and separates the burst data signals of the 8 own stations corresponding to the time series positions determined on the transmitting side for each station.

Next, the time-series position inverse conversion circuit converts the gust-like data signal into a fixed channel in the time series, and the frequency conversion circuit extracts it as the original data signal. It is characterized by preventing leakage of the contents of data signals to receiving stations other than those between transmitting and receiving stations.

〔Example〕

Hereinafter, one aspect of the present invention will be explained in detail.

FIG. 3 is a schematic diagram of a time division multiplex communication device using the present invention, and FIG. 4 shows timing for explaining the present invention.

Now, when data signals are sent from the transmitting station 30& to the receiving station 36a, from the transmitting station 30b to the receiving station 36b, and from the transmitting station 30c to the receiving station 36c.

The data signals of each transmitting station are converted into burst data signals by transmitting interface circuits 301a, jolb, and 301c, respectively. The relationship is shown in FIG. Next is the 1-time series position conversion circuit 302a.

At 302b and 302c, positions are converted in time series so that the burst data signals of the respective transmitting stations do not collide with each other in each frame in each multi-frame period. The timing of this relationship is shown in FIG.

Each transmitting station data signal is sent to the ninth-order multiplexing circuit 303, where it is multiplexed and sent to the receiving station in a time-series positional relationship as shown in FIG.

On the other hand, each receiving station has a channel selection circuit 304a.

From among the signals received at 304b and 304c, a burst signal is selected according to the time-series position in each frame by the corresponding transmitting station, and the burst signal corresponding to the own station is separated as shown in Fig. 7. do. Furthermore, the primary time-series position inverse conversion circuits 305a, 305b, and 305c rearrange the data signals into constant channel burst data signals as shown in FIG. Each original continuous signal is demodulated.

Expressing the above in a concrete formula, the number of channels to be multiplexed is N (N is an integer where N>1), and one frame is composed of m frames (rn is the number of u where m>1). If so, in the case of the conventional system, the signal of another station is selected once every N ways, but in the case of the 7-way system, the signal of another station is selected once every Nnn times. This is an increase of Nrn-N times compared to the conventional method. For example, the number of channels is 8 channels.

If one multiframe is composed of 10 frames, in the conventional system, the signal of another station must be selected once in every eight ways. However, in the case of one-piece method, 8” =
1,073,741,824 messages are received every 9 times, which is an increase of 1,073,741,816 messages compared to the conventional method, making it extremely difficult to select any receiving station other than the own station. .

〔Effect of the invention〕

According to this method, since each transmitting station performs position conversion on a time-series basis for each frame at a multi-frame period, the receiving station side does not know the time-series position of the transmitting station corresponding to itself. If so, it is possible to extract the original data signal by selectively separating the burst-like data signal of the own station and inversely converting the two time series positions. However, since the number of combinations of positions above any receiving station other than the own station is extremely large depending on the number of channels and the number of frames in one multiframe, it is very difficult to select this position.

As described above, by using the present invention, it is possible to prevent leakage of data signal contents to receiving stations other than between corresponding transmitting/receiving stations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional time division multiplex communication device. FIG. 2 is a diagram showing the timing of burst data signals at each part in FIG. FIG. 3 is a block diagram showing a time division multiplex communication device using the present invention. FIGS. 4 to 8 are diagrams showing the timing of burst data signals in each part of FIG. 3. FIG. 4 shows the nostril-like data signals at points 31a, 31b, and 31a. FIG. 5 shows a burst data signal after time-series position conversion at points 32a', 32b, and 32a. Figure 6 shows multiplexed signals at 33 points. Figure 7 shows 34a, 34. b, Channel-selected burst-like data signal at point 34c. FIG. 8 shows the twisted data signals at points 35a, 35b, and 35a. In the figure, 10a to 10c, 30a to 30c are transmitting stations, 14
．． a to 14c and 36a to 36c are receiving stations. 101a to 101c, 301a to 301c are transmission interface circuits, 102 and 303 are multiplexing circuits, 103
a~] 03 c, 304 a ~304. c is a channel selection circuit. 104 a ~ 104 c, 306 a ~ 306
c is a frequency conversion circuit, and 302a to 302C are time-series position conversion circuits. 305a to 305C are time-series position inverse conversion circuits.

Claims (1)

[Scope of Claims] (1) A transmission interface circuit that transmits input data signals to predetermined time-series positions (hereinafter referred to as channels) in a /J-streak pattern, and a transmission interface circuit that transmits input data signals from N transmission interface circuits. A transmission system includes a multiplexing circuit that performs time division multiplexing (TDM) of N columns of burst data signals of mutually different channels. A channel selection circuit selects and separates an arbitrary channel from the output signal of the transmission system, converts the frequency of the burst data signal in the selected channel, and sends the N channels to the transmission system in time series. A time-series position conversion circuit that performs time-series position conversion on a frame-by-frame basis to avoid collisions is provided on the output side of the transmission interface circuit, and in the receiving system, the time-series position conversion circuit performs time-series position conversion on a frame-by-frame basis. Only the burst data signal of the own channel is selected by the channel selection circuit, and the output side of the channel selection circuit is provided with a time series position reverse signal for returning the burst data signal to a predetermined position on the time series. A time division multiplex communication device characterized by being provided with a conversion circuit.