JPH04183134A - Time division communication method for mobile body communication - Google Patents

Abstract

PURPOSE:To make a third person's radio transceiver not belonging to a system difficult to tap by changing the start point and sequence of reading time piece signals for each frame in accordance with instructions of a cipher signal. CONSTITUTION:When a signal by a switch SW78 flows to side a, since a time piece signal ciphered by a reversible time range memory circuit RTM1 adjusts transmission timing, the time piece signal is stored once in a memory circuit 1, read in accordance with reading instructions to be sent by a timing signal and from a cipher code adder 76, and sent to a signal rate converting circuit 51-1-1. Then, a signal (random number) from the cipher code adder 76 is represented in decimal notation, and if the signal is assumed to consist of more than 2 digits, the numeric value of the lowermost digit and the time length of the time piece signal are equally divided to 10, respectively, and a point of time is determined where a number of times of equally divided time division of the numeric value counting from point P are made to coincide with a number of times of equally divided time division of the time length, and that point of time is designated as reading point A. Next, by choosing the numeric value of the second digit, if it is an even number, the reading sequence is determined as positive, and if it is an odd number, the reading sequence is determined as negative.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a confidential communication method in time-division communication of mobile communication. More specifically, a radio channel is given, and one of the many mobile radios in the service area uses this to set up a radio link and communicate with the opposing radio base station. (The aim is to provide a method to improve the privacy of communications by eliminating the possibility that radio equipment that does not belong to the system tunes to the same radio channel and time slot and intercepts communication contents.) .

[Prior Art] In mobile communication using voice using a small zone method, a method employing a time division time compression multiplex signal is described in the following document.

Literature 1. Ito “Study of mobile phone system - Time division time compression F
Proposal of M modulation system-Pacific Institute of Electronics Engineers Technical Report RC389-11
July 1989 document 2. Ito ゛Study of mobile phone system - Theory study of hour/minute F1 time pressure compression M modulation system °° IEICE technical report RC889-
39 October 1989 In other words, in Document 1, a transmission signal (baseband signal) is divided into predetermined time intervals and stored in a memory circuit, and when read out, the speed is n times faster than the speed at which it is stored in the memory circuit. built into mobile radios and radio base stations in order to read out signals in predetermined time slots at high speed, angle-modulate or amplitude-modulate carrier waves with the signals accommodated by these time slots, and transmit and receive signals intermittently in time. a radio receiving circuit having receiving mixers facing each other and communicating with each other, a radio transmitting circuit having a transmitting mixer, a synthesizer applying voltage to the receiving mixer of the wireless receiving circuit, and a synthesizer applying voltage to the transmitting mixer of the wireless transmitting circuit. A switch circuit is provided for each to intermittent the output of the synthesizer applied to each, and this intermittent state is cycled for both transmission and reception, and the same intermittent transmission and reception as above is synchronized with that of the mobile radio for the radio base station communicating with the opposite. In order to extract only the signal accommodated in the predetermined time slot, the receiving side opens and closes the radio receiving circuit to receive the signal, demodulates the signal, and stores the obtained signal in the storage circuit. An example of a system that constructs a system that can reproduce the baseband signal, which is the original signal that was transmitted, by reading it at a low speed of 1/0 of the speed stored in this memory circuit when comparing the readings. It has been reported.

In addition, in Document 2, there is a study of adjacent channel interference and co-channel interference, which are problems when applying the above-mentioned TCM (time division time compression multiplexing) M method to small zones, and - Possibility of realizing the system has been shown by appropriately selecting parameters.However, there is a possibility that a wireless device that does not belong to the system tunes into the same radio channel or the same time slot and intercepts the communication content. However, it is necessary to prevent this from the viewpoint of privacy protection, and there is no known technology of this kind.

1 Invention or Problem to be Solved] In the system construction examples of Documents 1 and 2 mentioned above, a large number of transfers from a wireless base station are required. l) TCM sent to the radio (
Although a method for transmitting a TCM signal (time division time compression multiplexing) signal and a method for transmitting a TCM signal transmitted from a mobile radio device to a wireless base station in accordance with the method is disclosed, depending on the disclosed transmission method, the system However, there remains a problem that it is relatively easy to tune in to the radio channel and time slot in use by other radios that do not belong to the radio, and listen in on the contents of the communications.

[Means for Solving the Problems] When transmitting a CM signal, a radio base station stores the temporally compressed and segmented signals to be accommodated in each time slot in a frame to be communicated in a storage circuit. When storing and reading this, in the time domain of the temporally compressed signal contained in the delimited signal, start reading from there or change the reading order to the same order as the speech signal. The code is executed in accordance with the code retrieved from the code storage unit, and the type of code, encryption, and decoding are carried out in accordance with the code retrieved from the code storage unit. Added a function to instruct the method.

L effect] Regarding the transmission method in the time domain of the signal accommodated in the time slot to be used, the reading start point of the time piece signal (
Change where the readout point (hereinafter abbreviated as the readout point) starts and whether the readout start order (hereinafter abbreviated as the transmission order) is in a positive or reverse order for each frame according to the instructions of the encrypted signal. As a result, CM signals can now be equipped with high abbreviation functions equivalent to digital signals, so the readout points and transmission order in the time domain of signals accommodated in time slots can be adjusted. It becomes extremely difficult for a third party's wireless device not belonging to the system to listen in, as they do not know whether the order is forward or backward, and it is now possible to ensure the privacy of communications.

Embodiment 1 FIGS. 1A, 1B, and 1C show a system configuration for explaining an embodiment of the present invention.

In FIG. 1A, 10 is a general telephone network, and 20
t is a gateway switch for connecting the telephone network 10 and the wireless system. Reference numeral 30 denotes a wireless base station, which includes an interface with the gateway exchange 20, a circuit for converting signal speeds, a circuit for allocating and selecting time slots, a control section, etc. It has a wireless transmitting and receiving circuit that exchanges wireless signals with the mobile wireless devices 100 (100-1 to 100-n).

Here, between the barrier exchange 1120 and the radio base station 30, there is a transmission line that transmits communication signals 22-1 to 22-n including communication signals of communication channels CH1 to CHn and control signals.

FIG. 1B shows a circuit configuration of a mobile radio device 100 that communicates with a radio base station 30.

Received signals such as control signals and call signals received by the antenna section enter a radio reception circuit 135 including a reception mixer 136 and a reception section 137, and the communication signal output from the radio reception circuit 135 is sent to a speed restoration circuit 13B, a control section 140, and a clock signal. The signal is input to the regenerator 141.

Further, a part of the output of the receiving unit 137 is applied to the decryptor 175, and the code sent from the wireless base station 30 is decoded.
0 and is input to the encrypted time piece signal decoding circuit 179. The clock regenerator 141 regenerates a clock from the received signal and sends it to the speed restoration circuit 138 and the control unit 140.
is applied to the timing generator 142.

The speed restoration circuit 138 restores the speed (pitch in the case of an analog signal) of the segmented control signal or compressed and segmented communication signal in the received signal and sends it to the encrypted time piece signal decoding circuit 179. The encrypted time piece signal decoding circuit 179 has the same function as the encrypted time piece signal decoding circuit group 79 of the wireless base station 30, which will be described later, and receives the outputs of the decryptor 175 and the timing generator 142. ,
The telephone unit 101 and the control unit 140 as continuous signals.
is being entered.

In addition, the signals in the time slot, which is usually placed at the beginning of one frame, include a frame synchronization signal as well as an uncompressed control signal, and this control signal includes cryptographic information, etc. This is decoded by a decryptor 175 and input to the control section 140. There is a cipher storage unit 177 that stores cipher information (for example, a random number table), and this and the control unit 140 exchange information with each other.

In addition, when the mobile radio l11100 takes the lead in encrypting communications, the code storage unit 177 and the code adder 176 are used.

The communication signal output from the telephone unit 101 is input to the encrypted time piece signal forming circuit 178. This circuit has the same function as the encrypted time piece signal forming circuit group 78 of the wireless base station 30, which will be described later.

The code transmitted as a control signal from the wireless base station 30 is decoded by the decryptor 175, and the result is sent to the control unit 140.
Report to. According to the decrypted code, the control unit 140 instructs the encrypted time piece signal forming circuit 178 as to whether the time interval, timing, and transmission order of each time slot should be in the forward order or in the reverse order. The encrypted time piece signal forming circuit 178 converts the telephone signal into time pieces according to instructions from the control unit 140 and then sends the output to the speed conversion circuit 131 .

In the speed conversion circuit 131, the speed (pitch in the case of an analog signal) of the communication signal is made high (compressed) and applied to the wireless transmission circuit 132 including the transmission mixer 133 and the transmitter 134.

Further, in the timing generator 142, the clock regenerator 1
41 and a control signal from the control unit 140, the transmission/reception intermittent controller 123. Speed conversion circuit 131. It supplies necessary timing to the encrypted time piece signal forming circuit 178, the encrypted time piece signal decoding circuit 179, and the speed restoration circuit 138.

The mobile radio device 100 further includes a synthesizer 121-1.
6 and 121-2, and selector switch 122-1.122
-2 and a changeover switch 122-1.

The transmitter/receiver intermittent controller 123 and timing generator 142 that generate signals for switching the transmitter 122-2 are included, and the synthesizer 121-1, 121-2, the transmitter/receiver intermittent controller 123, and the timing generator 142 are controlled. 140. A reference frequency is supplied from a reference crystal oscillator 120 to each synthesizer 121-1, 121-2.

A wireless base station 30 is shown in FIG. 1C.

N-channel communication signal 22-1 with gateway switch 20
22-n are connected to a signal processing unit 31 forming an interface through a transmission path.

Now, the communication signal 22 sent from the Kanmon Traffic WA machine 20
−1 to 22-n are input to the signal processing unit 31 of the wireless base station 30. In the signal processing section 31, an amplifier for compensating for transmission loss is straightened, and so-called 2-wire to 4-wire conversion is performed. That is, the input signal and the output signal are mixed and separated, and the input signal from the barrier switch 20 is encrypted by the encrypted time piece signal forming circuit group 78 including the encrypted time piece signal forming circuits 78-1 to 7B-n. After the signal is converted into a signal, it is sent to the signal speed conversion circuit group 51.

The output signal from the signal speed restoration circuit ¥1-38 is decoded by an encrypted time piece signal decoding circuit group 79 including encrypted time piece signal decoding circuits 79-1 to 79-n, and then sent to a signal processing section. 31, and further transmitted to barrier exchange 1120 using the same transmission path as the input signal. Among the above input signals from the gateway exchange 20 are input to the encrypted time piece signal forming circuit group 78 and are divided into time intervals according to instructions from the encryptor 76.

Next, this output is sent to many signal speed conversion circuits 51-1 to 51-5.
The signal is input to a signal speed conversion circuit group 51 including signals 1 to 1n, and undergoes predetermined speed (pitch) conversion.

Further, the signal transmitted from the radio base station 30 to the gateway exchange 20 is inputted to the signal speed restoration circuit group 38 via the output of the radio reception circuit 35 or the signal selection circuit 39, and is speed (pitch) converted. The signal is input to the encrypted time piece signal decoding circuit group 79. In this circuit, as a result of dividing the telephone signal into time intervals according to instructions from the decryptor 75, the telephone signal is reproduced and input to the signal processing section 31.

Next, the operations of the encrypted time piece signal forming circuit group 78 and the signal speed converting circuit group 51 are illustrated in FIG. 2A-1.

This will be explained in detail using FIG. 2A-2 and FIG. 2A-3.

FIG. 2A-1 shows that among the encrypted time piece signal forming circuit group 7B and the signal speed converting circuit group 51 shown in FIG.
Encrypted time piece signal forming circuit 78 for speech channel number 1
-1 and signal speed conversion circuit 51-1 are selected, and the same operation is performed for communication channel numbers 2 to n, so communication channel number 1 is used as a representative. FIG. 2A-2 is a schematic diagram showing the signal processing state of each part of the circuit shown in FIG. 2A-1.

Now, in Figure 2A-1, from the K direction, Figure 2A-2 (a
A series of telephone signals from the call processing section 31 of > enters the encrypted time piece signal forming circuit 78-1. The detailed configuration of the encrypted time piece signal forming circuit 78-1 is shown in FIG. 2A-1, which includes a switch 5W78°, a time domain reversible memory circuit RTM1, and an 8-way M2° memory circuit M1. M2 is included, and their operations will be explained below.

Now, the output signal from the signal processing section 31 is the switch 5W7.
Enter into 8. This circuit cuts the signal at regular time intervals, and the time domain reversible memory circuits RTM1 and RTM1.
It has a function of alternately sending data to TM2. The eight time domain reversible memory circuits M1 and M2 perform the following operations. That is, the signal from the signal processing section 31 is transmitted to the switch 5W7.
8 is switched to the a side or the b side, the time piece signal is stored, and the next time it is read out, the control i! B
The readout point can be changed by a control signal from 42, and the time readout order can be changed forward or reverse in the time domain.

Hereinafter, the time domain reversible memory circuit R-m1, which is characteristic of the present invention.
RTM2 will be explained in more detail using FIG. 2A-3.

'(a) in Figure 2A-3 is a time domain reversible memory circuit RT
The time piece signal stored in M1 or M2 is shown.

As shown in the figure, it has the shape of a time piece signal divided by a storage start point and an end point PP', or it is simply a telephone signal divided into fixed time pieces as described above. However, in reading, the reading is not necessarily performed from point P, but according to the control signal from the coder 76, the reading point is read from the designated point A between PP', and the reading time order is also Also, according to the control signal from the cipher 76, the forward direction in the time domain, that is, the order indicated by the arrows D1 and D2 (L in the same figure (b), or the reverse direction, that is, the arrows d1 and d2
It has a function to read data in the order shown ((C) in the same figure).

The above operation will be explained in conjunction with the signal from the coder 76. If the trust @ (random number) of the coder 76 is expressed in decimal notation and has two or more digits, then the last value and the second A
-3 Divide the time length of the time piece signal shown in Figure (a) into 10 equal parts,
Divide it equally from point P and match it with a value several times higher (for example, 6/10 if it is 6), and determine that point as readout point A. Next, focusing on the second digit, if the number is even, the reading order is determined to be positive, and if it is odd, the reading order is determined to be the reverse order. Due to the above connection, the signal (random number) from the coder 76 corresponds to the time piece signal.

Figure 2A-3 (d) is a diagram for roughly explaining the operation of (b) or (c) above, and shows the storage start point P and end point P' of the flat time piece signal in (a). to create a ring-shaped time piece with no endpoint. Next, when the signal is disconnected at the point A<A') and re-stringed to create a flat time piece signal, the result is as shown in (e).

In this case, point A is the starting point in time, and point A' is the ending point.

By the way, point P (P') in (a) exists at the midpoint of AA' as shown in (e).

Also, when reading out a circular time piece signal, if it is read out clockwise (arrow D) from point A (A'), it will be read out in the positive direction.
Conversely, in the case of counterclockwise rotation (arrow d), reading is performed in the opposite direction.

Regarding the reverse order reading of the encrypted time piece signal explained above, a specific implementation method will be explained. The circuit is executed by the above-mentioned time domain reversible memory circuit RTMI or RTM2, but simply speaking, reverse order readout means recording an audio signal on a tape recorder, and when playing it back, the tape is rotated in the opposite direction. This corresponds to playing back the audio recorded first, and playing the audio recorded first last. To perform the same operation as above in a sophisticated way, do the following: That is, a timed analog telephone signal is digitized by an A/D converter and stored in a storage circuit (for example, RAM). Then, the data may be read out in a reverse chronological order, similar to the above-mentioned tape recorder, and then converted into analog data again using a D/A converter. By the above operation, the input time piece signal is converted into inverse time signal.

As is clear from the above explanation, when the signal from the switch 5W78 flows to the side a (Fig. 2A-1), the signal is encrypted by the time domain reversible memory circuit RTM1. In order to adjust the timing at the time of transmission, the signal is first stored in the storage circuit M1, read out according to the timing signal and the reading instruction sent from the coder 76, and sent to the signal speed conversion circuit 51-1-1. It will be done.

Above, we have explained the case where the signal from the switch 5W78 flows to the a side.Also, when the signal flows to the b side of the 5W78, the same processing as above is performed by the signal from the coder 76, and the time segmented telephone signal is The read point and whether or not it is to be detimed is determined, and it enters the signal rate converter 51-1-2 from the storage circuit M2.

These time domain reversible memory circuits RTM1 and 8th M2
The time piece signals which are the output of are shown in FIG. 2A-2(C), and these signals are inputted to the signal speed converter 51-1-1 or 51-1-2 and subjected to time compression, respectively. A signal shown in FIG. 2A-2(d) is output. The outputs are mixed to form one series of time-compressed signals shown in FIG. 2A-2(e), which is input to the signal selection circuit 528.

In the time signals shown in Figure 2A-2, the signals covered with diagonal lines on the upper right are signals that have not been converted to inverted time, and the signals covered with diagonal lines on the lower right are signals that have been converted into inverted time. Showing a signal.

Next, the operations of the signal rate restoration circuit group 38 and the encrypted time frame signal decoding circuit group 79 to which the output of the signal selection circuit group 39 is applied are explained in FIGS. 2B-1, 2B-2 and 2B-3.
This will be explained in detail with reference to the drawings.

Figure 2B-1 shows the signal speed restoration circuit group 3 in Figure 1C.
8 and the encrypted time frame signal decoding circuit group 79, only the signal speed restoration circuit 38-1 and the encrypted time frame signal decoding circuit 79-1 for the communication channel number 1 are selected, .about.n is also performed in a similar manner, so the communication channel number 1 is used as a representative. FIG. 2B-2 is a schematic diagram showing the signal processing state of each part of the circuit shown in FIGS. 2B-1.

Now, in Figure 2B-1 and Figure 2B-2,
Figure 2B-2 (a:l) The signal speed restoration circuit 3B-
] is input. The signal speed restoration circuit 38-1
-1 As shown in Figure 1, it includes a switch 5W38 and a signal speed restorer 38-1-1.38-1-2, and the switch 5W38 installed at the input end is switched to the a side or the b side. This is performed cyclically by receiving a timing signal from the timing generation circuit 42 and in synchronization with the time slot within the frame.
The time signal shown in FIG. 2B-2(b) is obtained at the terminal on the b side. This time signal, including the compressed telephone signal within each frame, is processed by signal rate restorer 381-1.38-1-
2 to restore the original speed to obtain the restored time signal shown in FIG. 2B-2(C). These are sent to the Sho code time piece signal decoding circuit 79-1.

The encrypted time piece signal decoding circuit 79-1 includes a plurality of memory circuits M3. M4 and time-domain reversible memory circuit Rd M3. The operation is performed by the encrypted time piece signal forming circuit 78 shown in FIG. 2A-1.
-1 is the opposite, and the original telephone signal is thereby regenerated.

! 2 Signal speed restorer 3B-1 in Figure B-2 (C)
The output arrives at the time domain reversible memory circuit RT M 3 of the encrypted time piece signal decoding circuit 79-1. This circuit is controlled by a signal from the decryptor 75, and it will be explained with reference to FIG. 2B-3 that this signal faithfully reproduces the originally transmitted telephone signal.

FIG. 2B-3(a) shows an encrypted time piece signal input to eight time domain reversible memory circuits M3 or RTM4. (b) of the same figure shows that when reading out the signal in (a), a control signal from the decryptor 75 is obtained to determine the readout point P, the readout direction (positive direction indicated by arrows D1 and D2), and the readout end point in the time domain. In addition, (C) shows the case in the read direction or in the reverse time direction (reverse direction indicated by arrows d'l and d2). 42 and a control signal from the decryptor 75 are output to the signal processing section 31.

The above is the output signal from the signal speed restorer 38-1-1, but the output signal from the signal speed restorer 38-1-2 is also processed in the same manner as above, and the time domain reversible memory circuit 8 M4 Then, 1q of the time signal shown in FIG. 2B-2(d) is obtained from the memory circuit M4. These output signals are mixed and output as a series of telephone signals to the signal processing section 31, or the telephone signals are faithfully reproduced as the original signal without any discontinuity or overlap. .

Here, also in each time signal of Fig. 2B-2,
As in Figure 2, diagonal lines are drawn upward to the right or downward to the right, but the diagonal lines upward to the right indicate the positive order, and the diagonal lines downward to the right indicate the reverse order, indicating that each time signal includes a telephone signal. It is shown that.

Now, the control of the radio reception circuit 35 or the output of the call signal is performed by a signal selection circuit 39 that selects a signal for each time slot.
-1 to 39-n is input to the signal selection circuit group 39,
Here, speech signals are separated corresponding to each speech channel CH1 to CHn. This output undergoes signal speed (pitch) restoration in a signal speed restoration circuit group 38 including signal speed restoration circuits 38-1 to 38-n provided for each channel, and then is input to the signal processing section 31. , after undergoing 4-wire to 2-wire conversion, this output is sent to the barrier switch 20 as communication signals 22-1 to 22-2.
2-n.

Next, the functions of the signal speed conversion circuit group 51 will be explained.

By storing input signals such as audio signals and control signals divided into fixed time lengths in a memory circuit, and reading them out at a speed that is 15 times faster than when they were stored, the signal time can be stored. It becomes possible to compress the length. The principle of the signal speed conversion circuit group 51 is the same as when playing back audio recorded by a tape recorder at high speed, and in reality, for example, a CCD (Charge C
), BBD (Buc
Brigade Device) can be used, and the memory used in television receivers and tape recorders that compress or expand the time axis of conversation can be used (References: Koita et al. A tape recorder that compresses and expands 'Nikkei Electronics, July 26, 1976, pp. 92-133).

The circuit using COD or BBD exemplified in the signal speed conversion circuit group 51 can be used as it is in the signal speed restoration circuit group 38 as described in the above-mentioned literature. This can be achieved by making the reading speed slower than the writing speed by receiving a timing signal from a timing generator 42 that generates timing based on the clock and a control signal from the control unit 40.

The control or audio signals outputted from the barrier switch 20 via the signal processing unit 31 are input to the signal speed conversion circuit group 51, and after speed (pitch) conversion processing is performed, signals are assigned to each time slot. It is applied to the signal allocation circuit group 52. Is this signal allocation circuit group 52 a buffer? - A memory circuit that stores one section of high-speed signals output from the signal speed conversion circuit group 51, and converts the signals in the buffer memory using timing information from the timing generation circuit 42 given in accordance with instructions from the control unit 40. is read out and transmitted to the wireless communication circuit 32. As a result, when viewed in terms of channel correspondence, communication signals are arranged in series without overlapping in chronological order, and when all control signals or communication signals, which will be described later, are implemented, they appear as if they were continuous signal waves. become.

The state of this compressed signal is shown in FIG. 2C and will be explained.

The output signal of the signal speed conversion circuit group 51 is sent to the signal assignment circuit group 5.
2 and are given time slots in a predetermined order. SDO, SDl in Figure 2C (a)
, SD2., SDn indicate that the speed-converted communication signals are allocated to each time slot.

Note that each frame F1. F2. F3. The first time slot SDO of .
Contains call signals and/or control signals in response to calls from. If a speech signal is not implemented, the speech signal portion is supplemented with an empty slot signal, or in some systems no signal is transmitted at all, including the carrier wave.

In this way, as shown in FIG. 2C (a), in the wireless transmission circuit 32, the time slots SDO, SD
A signal forming one frame from 1 to SDn is applied to the modulation circuit. The time-series multiplexed signal to be transmitted is angularly modulated in the radio transmission circuit 32, and then sent out into space from the antenna section.

When making or receiving a telephone call, the wireless base station 30
As mentioned above, the control signal transmission between the mobile radio 1fi100 and the time slot SDO
However, depending on the system, it is possible to use either in-band or out-of-band telephone signals. Figure 3A shows these frequency relationships. That is,
Figure (a) shows an example of an out-of-band signal, and as shown in the figure, there are signals on the low frequency side (250Hz>
> can be used. This signal is also used, for example, when it is desired to send a control signal during a call, or when a signal is being encrypted, which will be described later.

FIG. 3A (b) shows an example of an in-band signal, which is used when making and receiving calls.

Although the above examples were all tone signals, it is possible to transmit many types of signals at high speed by increasing the number of tone signals or by modulating the tone and making it into a subcarrier signal.

The above was a case of analog signals, but if a digital data signal is used as a control signal, it is also possible to digitally encode the audio signal and time-division multiplex the two to transmit. The circuit configuration of is shown in FIG. 3C. In this system, an audio signal is digitized by a digital encoding circuit 91, and then it and a data signal are digitized by a multiplex conversion circuit 9.
This is an example of a case where the signal is multiplexed by 2 and applied to a modulation circuit included in the wireless transmission circuit 32. Then, by receiving it with the opposing receiver and performing the operation opposite to that shown in FIG. 3C in the demodulation circuit, it is possible to extract the audio signal and the NJ control signal separately.

On the other hand, the signal g sent from the wireless device 100 is received by the antenna section of the wireless observation station 30, and is received by the wireless receiving circuit 3.
5. Figure 2C (b) shows this upstream input 1
is a schematic representation of a bow.

That is, the valley frame F1. F2. F3. ... time slot SU1. SU2. −． 5IJn is a mobile radio 100-1.100-2. . . , indicates a communication signal addressed to the wireless base station 30 from 100-n.

Also, each time slot SU1. SU2. ..., Su
If the contents of n are shown in detail, it consists of a call signal and/or a control signal, as shown in the lower left of FIG. 2C (b). However, move! ! From line equipment 100 to wireless base station 3
If you want to perform emergency communication to the calling party to 0, time slot SUO placed at the beginning of the constant frame
use.

Now, among the input signals that have arrived at the radio base station 30, the control signal is immediately sent to the control section 40 from the radio reception circuit 35.
added to. However, depending on the magnitude of the speed conversion rate, it is also possible to apply the call signal to the control unit 40 from the output of the signal speed restoration circuit group 38 to a bond that has undergone similar processing. Further, the call signal is applied to the signal selection circuit group 39.

The signal selection circuit group 39 receives a timing signal from the timing generation circuit 42 that generates a predetermined timing according to a control signal instruction from the control unit 40, and synchronizes each time slot SU1 to SU5 (Jn). signal, control signal, or speech signal are separated and output. Each of these signals is input to the signal speed restoration circuit group 38. As already described in detail, this circuit
It has a function of performing inverse conversion of the speed conversion circuit 131 (FIG. 1B) at 0, so that the original signal is faithfully reproduced and transmitted to the gateway exchange 20.

The manner in which signals are transmitted in a signal space according to the present invention will be explained below using the required transmission band and the relationship between this and adjacent wireless channels.

As shown in FIG. 1C, the control signal from the control section 40 is applied to the wireless transmission circuit 32 in parallel with the output of the signal allocation circuit u52. However, depending on the magnitude of the speed conversion rate, it is also possible to apply the signal to the wireless transmission circuit 32 from the output of the signal allocation circuit group 52 after performing the same processing as the call signal.

Next, as shown in FIG. 1B, the mobile radio device 100 also has a circuit configuration required when the radio base station 30 has one communication channel among its functions.

Original signal, for example, an audio signal (0.3kHz to 3.0kHz7)
) passes through the signal speed conversion circuit group 51 (FIG. 1C), the frequency distribution on the output side is as shown in FIG. 3B. In other words, if the audio signal is converted 15 times as described above, the frequency distribution of the signal will be < 4 as shown in Figure 3B.
．． This means that the frequency is expanded from 5kHz to 45kHz.

Here, although the frequency distribution of the signal has been expanded, it should be noted that the waveform form has simply been stretched along the frequency axis, and the waveform itself has not changed. Now, FIG. 3B shows a case where the control signal is simultaneously transmitted using the lower frequency band of the audio signal. Of these signals, a control signal (0,2~4.0kHz2> and a speech signal CH1 (4,5~45kHz expressed as SDl) are assigned to a time slot, e.g.
Suppose that it is housed in Other time slot SD2
The same applies to the audio signals accommodated in ~SDn.

That is, time slot so; <r=2°3,
-, n> accommodate a control signal (0.2 to 4.0 kHz) and a communication signal CHi (4.5 to 45 kHz). However, the signals in each time slot are arranged in chronological order, and the signals in multiple time slots are not applied to the wireless transmission circuit 32 at the same time.

These call signals are sent to the wireless transmission circuit 32 along with control signals.
When added to the angle modulation section included in the above, the required transmission band requires at least fc±45kHz. However, fo is a radio carrier frequency. If there are a plurality of wireless channels given to the system, the speed-up of the signal by the signal speed conversion circuit group 51 is limited to a certain value due to the limitations on these frequency intervals. The frequency interval of multiple wireless channels is f
rep and the maximum signal speed due to the above-mentioned speed increase of the audio signal is fH, then the following inequality must hold between the two.

f > 2f ■ ep On the other hand, in digital signals, audio is usually digitized at a speed of about 64 kb/s, so it is necessary to read the scale on the horizontal axis in Figure 3B, which explains the case of analog signals, by raising it by about one digit. However, the relationship in the above equation also holds true in this case.

Further, the control signal input from the mobile radio device 100 to the radio base station 30 is input to the radio reception circuit 35, but a part of the output is input to the control unit 40, and the other part is input to the signal selection circuit group 39. The signal is sent to the signal speed restoration circuit group 38 via the signal speed restoration circuit group 38. After the latter control signal undergoes a speed conversion (change to a low speed signal) that is completely opposite to that at the time of transmission, it becomes the same signal speed as that used in the general telephone network 10 and is transmitted via the signal processing section 31. and is sent to the barrier exchange 20.

Finally, we will explain secret techniques when considering system elements.

The transmission of decryption information is of the utmost importance, since communication itself is impossible unless the desired recipient decrypts the polarized signal during signal transmission. Therefore, in the TCM system, it is necessary to apply the following technology.

i) Frame (bit) synchronization ii) Highly reliable transmission of control signals In order to satisfy the above requirements i> and 2) in a mobile communication system that is subject to poor fading conditions, the following technology is required.

<a>I > by Diperity Technology, ii) Improvement (b)' Improving the reliability of the confidential communication system As for (a), a known method can be adopted, so (b) will be explained.

The other party's radio equipment has a highly stable crystal oscillator (the reference crystal oscillator 120 in FIG. 1B corresponds to this) and the same cryptographic memory unit as the own radio station (the cryptographic memory unit 177 in FIG. 1B).
(corresponds to this), at the beginning of communication, an instruction signal is sent saying "from what page, what line, what character", and if the other party receives this successfully, the control signal is sent after that with some fading. Even if it becomes impossible to receive the code, a method such as continuing to decrypt the code using autonomous synchronization may be adopted.

Next, the call originating/receiving operation of the system according to the present invention will be explained by taking the case of a voice signal as an example.

(1) Call origination from mobile radio device 100 This will be explained using the flowcharts shown in FIGS. 4A and 4B.

Mobile radio I! When the wireless base station 100 is turned on, the wireless receiving circuit 135 in FIG.
0 → mobile radio 100) radio channel (channel CH1
) is included! l Start capturing the control signal. If the system is provided with multiple radio channels, j〉 indicates the maximum received input electric field.
Radio channel indicated by Shinyumi iii) Receiving status of the radio channel (hereinafter referred to as channel CH1) according to the procedure defined in each system, such as channels with empty time slots among the time slots within the radio channel. Enter. This corresponds to the time slot SD in each frame F1.F2.-- shown in Figure 2C (a).
This is possible by capturing the synchronization signal within i. The control unit 140 sends a control signal to the synthesizer 121-1 to generate a local frequency that enables reception of the wireless channel CH1, and the switch 122-1 is also fixed to the synthesizer 121-1 side. It is in.

Therefore, when the receiver of the telephone unit 101 is off-hook (starting calling) (3201, FIG. 4A), the synthesizer 121-2 in FIG. 1B generates a local frequency that enables transmission on the wireless channel CH1. A control signal is received from the control section 140 to cause the control to occur.

Further, the switch 122-2 is also turned to the synthesizer 12]-2 side and becomes fixed. Next, the wireless channel CHI
The call control signal outputted from the telephone carrier section 101 is sent using the telephone carrier section 101. This υj (company) 1 word is transmitted using the frequency band shown in Section 3A (b) using, for example, time slot SUO.

The transmission of this control signal is limited to time slot SU◯, and is sent in bursts, and no signal is sent during other time periods, so it does not adversely affect other communications. However, if the speed of the limiting signal is relatively slow, or the amount of information in the signal is too large to be accommodated in one time slot, the same time slot of the next frame or - Transmitted using slots.

Specifically, the following method is used to capture the time slot SUO. The control signal transmitted from the radio base station 30 includes a synchronization signal and a subsequent control signal, as shown in FIG. It becomes possible. Furthermore, this i control signal includes 11@ information such as currently used time slots and unused time slots (empty time slot display). Depending on the system, the time slot SDi (i=1.2°・
..., n) may contain only periodic signals and speech signals when they are being used by other communications, but even in such cases, unused time slots usually contain synchronization signals and control signals. By receiving this control signal, the mobile radio va100 can know which time slot should be used to send out the calling signal.

Note that if all time slots are in use,
It is not possible to make a call on this radio channel and it is necessary to sweep and search for another radio channel.

In other systems, there may be no empty slot indication in any of the time slots, in which case the audio multiplex signal SDI that follows.

SD2. ---, it is necessary to search for the presence of SDn one after another and check for empty time slots.

Now, returning to the main topic, the mobile radio device 100 that has received the control information sent from the radio base station 30 by one of the above methods should transmit a call control signal in which time slot. It is possible to make a judgment including the transmission timing.

Also, when encrypting communication signals in a system led by the wireless base station 30, at this point the mobile wireless! l! 11
00 has received the cipher information, and once communication is started, the control unit 140 can enter a standby state for the cipher to be given to the encryption time smoke signal forming circuit 17B. However, confidential conversations will not be made until the call has started.

Assuming that time slot SUO for uplink signals is an empty slot, it is decided to use this empty time slot, and a control signal for calling is sent out, and the necessary timing is extracted from the response signal from the wireless base station 30. It is also possible to send out burst-like control signals.

If a call is made from a mobile radio at the same time, the call signal will not be properly transmitted to the radio base station 30 due to call collision, and the operation will have to be restarted from the beginning, but this probability is When viewed as a system, this value is kept to a sufficiently small value. If k further reduces call collisions, the following method is taken. If the mobile radio device 100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but rather uses only the first half of the time slot for some mobile radio devices and only the second half for other mobile radio devices. This is a method that allows you to use it.

In other words, the portion of the time slot used as a calling signal is divided into several types, and this is used to classify a large number of mobile radios into groups, and each group is assigned a time period within that one time slot. It is a way of giving. Another method is to create many types of frequencies for control signals, group a large number of mobile radios, and give these to each group. According to this method, even if control signals of different frequencies are transmitted simultaneously using the same time slot, no interference will occur at the radio base station 30. The above two methods may be used separately, or when used together, the effects will increase synergistically.

Now, the control signal for calling from the mobile radio device 100 is successfully received by the radio base station 30, and the control unit 40 receives the mobile heat 8! R10
Suppose that an ID (identification signal) of 0 is detected (S202>
, sends the communication channel designation signal and encryption information necessary for making a call to the mobile radio device 100 in the downlink time slot S.
Transmit to the mobile radio device 100 using DO (S203
>.

The mobile radio device 100 that has received the control information sent from the radio base station 30 searches the code storage unit 177 from the code information, frame number, and communication channel to find the time slot number assigned to itself. Switch to the specified time slot SU1 (S204>,
Using this, the slot switching completion signal is sent to the wireless base station 30.
(3205>) and wait for a dial tone to be sent (5206>).

The radio base station 30 naturally expects this and is waiting for reception, and upon receiving the slot switching completion report (3207>
, sends a calling signal together with the ID of the mobile radio device 100 to the gateway exchange 20 (3208>.In response, the barrier exchange 20 turns on the necessary switches among the switches included in the barrier exchange 20, A dial tone is sent to the wireless base station 30 (S210, FIG. 4B).

This dial tone is transferred by the radio base station 30 using time slot SD1 (S211>, and the mobile radio 100 confirms that the communication path has been set (3212>). When transitioning to this state Mobile radio device 10
Since a dial tone can be heard from the handset of telephone section 101 of 0, transmission of a dial signal begins. This dial signal is speed-converted by a speed conversion circuit 131 and sent to the transmitter 1.
34 and a wireless transmission circuit 132 including a transmission mixer 133
It is sent using the upstream time slot SU1 (
5213). Thus, the transmitted dial signal is received by the radio receiving circuit 35 of the radio base station 30. This radio base station 30 already responds to the calling signal from the mobile radio 100, gives the time slot to be used, and operates the signal selection circuit group 39 and signal allocation circuit group 52 of the radio base station 30. Then, it receives the uplink time slot 5LJ1 and shifts to the state of transmitting the signal of the downlink time slot SD1. Therefore, the dial signal transmitted from the mobile radio viA100 passes through the signal selection circuit 39-1 of the signal selection circuit group 39, and then enters the encrypted time piece signal decoding circuit group 79 via the signal speed restoration circuit group 38. Here, the original transmission signal is restored and transferred to the gateway exchange 20 as a call signal 22-1 via the signal processing unit 31 (3214>, and a call path to the telephone network 10 is set (3215>).

On the other hand, an input signal from the barrier switch 20 (initial control signal,
When a call is started, the call signal) is polarized in the encrypted time piece signal forming circuit group 78 via the signal processing unit 31 in the radio base station 30, and the polarized signal is polarized in the signal speed converting circuit group 51. After undergoing speed conversion at , the time slot SD1 is given by the signal allocation circuit 52-1 of the signal allocation circuit group 52. and wireless transmission circuit 32
The data is transmitted to the mobile radio device 100 using the time slot SD1 of the downlink radio channel.

The mobile radio device 100 is waiting for reception in time slot SD1 of the radio channel Cl-11 and is received by the radio reception circuit 135, the output of which is sent to the speed restoration circuit 1.
38. In this circuit, the original signal of the transmission is restored and input to the handset of the telephone section 101. Thus, a call is started between the mobile radio device 100 and a regular telephone within the regular telephone network 10 (3216>).

Furthermore, as mentioned above, the wireless base station 30 and the mobile radio 1100 are both ready for the secret conversation, and once the conversation starts, it is immediately executed.

To do this, the control unit 40 sends the coder 7 at the same time as the start of the call.
6 to start the operation.

Note that the communication between the radio base station 30 and the mobile radio l1100, such as the above-mentioned call channel assignment, is performed before the start of the call.
Confidential communication is also possible in communication for control during the period, and the explanation is omitted because it is not very practical.

The call is terminated by on-hooking the handset of the telephone unit 101 of the mobile radio device 100 (3217>), and transmitting the end-of-call signal, the on-hook signal from the control unit 140, and the speed conversion circuit 1.
31 from the wireless transmission circuit 132 to the wireless base station 30 (S218>, the control unit 140 stops the operation of the transmission/reception intermittent controller 123 and switches the switches 122-1 and 122-2 to the synthesizer. It is fixed to the output ends of 121-1 and 121-2.

On the other hand, in the control unit 40 of the radio base station 30, the mobile radio 11
Upon receiving the call termination signal from 100, the call termination signal is transferred to the gateway exchange 20 (3219>), and the switch group (not shown) is turned off to terminate the call (S220>).

At the same time, the signal selection circuit group 39 and signal allocation circuit group 52 in the radio base 830 are opened.

In the above explanation, control signals between the radio base station 30 and the mobile radio device 100 are controlled by the signal speed conversion circuit group 51. Although it was explained that the signal does not pass through the signal speed restoration circuit group 38, etc.,
This is for the convenience of explanation, and communication can be carried out without any problem even through the signal speed conversion circuit 51, signal speed restoration circuit group 38, control signal speed conversion circuit 48, or signal processing section 31 in the same way as with audio signals. .

(2) Incoming call to mobile wireless device 100 The mobile wireless device 100 is on standby with the power turned on. In this case, as explained in the section on making a call from the mobile radio [100], the mobile radio [100] is in a waiting state to receive a downlink control signal on the radio channel Ctl in accordance with the procedure determined by the system.

Assume that an incoming call signal to the mobile radio device 100 arrives at the radio base station 30 from the general telephone network 10 via the barrier exchange 120. These control signals are processed as communication signals 22 in the same way as audio signals by the signal processing unit 31° encrypted time piece signal forming circuit group 78. The signal passes through five signal speed conversion circuit groups and is transmitted to the control unit 40 (FIG. 1C) via the signal assignment circuit group 52.

Then, the control unit 40 selects an empty slot among the downlink time slots of the radio channel CH1 addressed to the mobile radio device 100,
For example, using SDI, the mobile radio device 100 transmits an ID signal, an incoming call signal, a signalman time slot use signal (for example, SUL corresponding to SDl is used for transmission from the mobile radio device 100).

Mobile radio device 100 receives this signal and transmits it from receiving section 137 of radio receiving circuit 135 to control section 140 . In the suburban area 140, this signal is transmitted to its own mobile radio II.
To confirm that it is an incoming call signal to I'100, the telephone unit 101 makes a ring tone and at the same time calls the designated time slot SD1. The transmission/reception intermittent controller 123 is operated to stand by at SU1, and the switches 122-1 and 122-2 are started to be turned on and off. In this way, the state has shifted to a state in which calls can be made.

Note that it is clear that confidential communication can be performed for incoming calls as well as for outgoing calls. Furthermore, the secret technology described in the present invention allows a third party who does not belong to the system to use fP=
It is clear that this makes the possibility of doing so extremely difficult. This is because the reading point in the time domain and the forward or reverse transmission order of the signal accommodated in a time slot that is stopped in a time frame are changed for each frame according to the instruction of the encrypted signal. - Even if the slot signal can be received, it is not known whether or not there is a time domain inversion. Therefore, since the same state continues in the next frame signal, a large amount of noise is mixed in, making it impossible to listen to the signal.

[Effects of the Invention] As is clear from the above explanation, the secret method for TCM signals, which has not been disclosed in the past, has become practical, making it difficult for a third party's radio equipment that does not belong to the system to listen in. The effect of being able to ensure privacy in TCM communication is significant.

[Brief explanation of the drawing]

Figure 1A is a conceptual block diagram showing the concept of the system of the present invention, Figure 1B is a circuit diagram of a mobile radio used in the system of the present invention, and Figure 1C is a wireless base used in the system of the present invention. Figure 2A-1 is a circuit diagram showing the internal configuration of the encrypted time piece signal forming circuit and signal speed conversion circuit, which are the components of Figure 1C. Figure 2A-2 is the circuit diagram of the station. 2A-3 is an operation diagram for explaining the operation of the time-domain reversible memory circuit which is a component of FIG. Figure 1 is a circuit configuration diagram showing the internal configuration of the signal speed restoration circuit and encrypted time piece signal decoding circuit, which are the components of Figure 1C, and Figure 2B-2 is a diagram of each part of the circuit shown in Figure 2B-1. 2B-3 is an operation diagram for explaining the operation of the time-domain reversible memory circuit, which is a component of FIG. 2B-1, and FIG. 2C is used in the system of the present invention. A time slot structure diagram for explaining time slots, Figures 3A and 3B are spectrum diagrams showing spectra of speech signals and control signals, and Figure 3C is a circuit configuration diagram for multiplexing voice signals and data signals. , 4A and 4B are flow charts showing the flow of operation of the system according to the present invention. 10... Telephone network 20... Gateway switchboard 22
-1 to 22-n...Communication signal 30...Radio base station 31...Signal processing section 32
...Wireless transmission circuit 35...Wireless reception circuit 38.
... Signal speed restoration circuit group 39 ... Signal selection circuits 39-1 to 39-n ... Signal selection circuit 40 ... Control section 41 ... Clock generator 42 ... Timing generation circuit 51 ...・Signal speed conversion circuit group 51-1 to 51-〇...Signal speed conversion circuit 52...
Signal allocation circuit 75...Decryptor 76...FM
@Adder 77--Encryption storage unit 78...Abbreviated time piece signal forming circuit group 79...@Encoded time piece signal decoding circuit group 91...Digital encoding circuit 92...Multiple conversion circuit 100.100-1 to 100-n-...mobile inorganic machine 10
1...Telephone unit 120...Reference crystal oscillator 1
21-1.121-2...Synthesizer 122-1.
122-2...Switch 123...Transmission/reception intermittent controller 131...Speed conversion circuit 132...Wireless transmission circuit 133...Transmission mixer 134...Transmission unit 135
... Radio reception circuit 136 ... Reception mixer 137.
...Receiving section 13B...Speed restoration circuit 141.
...Clock regenerator 175...Code decoder 176...Code adder 1
77... Encrypted storage unit 178... Encrypted time piece signal forming circuit 179... Encrypted time piece signal decoding circuits M1 to M4... Storage circuits RTM1 to RTM4... Time domain reversible storage circuit 5W3
8.5W78...-Switch. Among the agents 1) ωH t −+ in the Kosan (one idiot) section H ω of the α-tei in Figure 2A-2 Figure 2A-3 (Dark-1 in Figure 2B-2) 2 Figure 2B-3 3A Diagram L Momentum 1 1

Claims (1)

[Scope of Claims] Each radio base means (30) each covers a plurality of zones to constitute a service area, and a frame structure for moving across the plurality of zones and communicating with the radio base means. a barrier exchange means (20) for exchanging communications with each mobile radio means (100) using a radio channel carrying temporally compressed delimited signals in time slots of In a communication method, the temporally compressed delimited signal is created to be accommodated in each time slot in oppositely communicating frames;
When storing and reading this, the reading start point and reading order in the time domain of the temporally compressed signal contained in the segmented signal are set to the same normal order as the speech signal. A time-division communication secret method for mobile communication, wherein at least one of the radio base means and the mobile radio means communicating oppositely communicates in a reverse order with respect to a call signal.