JPH04150322A - Time division communication privacy calling method for mobile object communication - Google Patents

Abstract

PURPOSE:To ensure the communication privacy by ciphering the time length of each frame given to a transmission signal at a radio base station and varying the time length of each time slot accordingly. CONSTITUTION:An input signal from a gate exchange is inputted to a cryptographic time segment signal generating circuit group 78 in a radio base station 30 and segmented at a time interval according to the instruction of a cryptographic imparting device 76. Then the output is inputted to a signal speed conversion circuit group 51, in which the signal is subjected to prescribed speed conversion, and time slot arrangement is decided in a signal assignment circuit group and the time length of one frame is changed to a value designated by the cryptographic imparting device 76 and sent to a mobile radio equipment 100 via a radio transmission circuit 32. A cryptographic decoder 175 in the radio equipment 100 decodes the cryptography and inputs the result to a cryptographic time segment signal decoding circuit 179. Then the signal speed is decoded by a speed decoding circuit 138 and the signal is regenerated by referencing the cryptography storage section 177. Thus, interception by a radio equipment not belonging to the system is made difficult.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a confidential communication method in time-division communication of mobile communication. More specifically, a certain radio channel is given, and one of the many mobile radios in one novice area uses this to set up a radio link and communicate with the opposing radio base station. Among these, the aim is to eliminate the possibility that a wireless device that does not belong to the system tunes to the same radio channel and time slot and intercepts the communication content, thereby improving the privacy of communication. .

[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: Mobile phone system study - Time division time compression F
Proposal of M modulation method-' IEICE branch axis RC38911 July 1989 document 2. Ito “Mobile phone system inspection – Time division time compression F
Theoretical study of M modulation system” IEICE branch axis RC889-39
In October 1989, in Document 1, a transmission signal (baseband signal) is divided into predetermined time intervals and stored in a storage circuit, and when read out, the speed is faster than the speed at which it is stored in the storage circuit. In order to read data at a predetermined time thrower 1~ at n times higher speed, angle-modulate or amplitude modulate the carrier wave with the signal accommodated by this time thrower 1~, and transmit/receive intermittently in time. A radio receiving circuit that has a receiving mixer that communicates with each other in a mobile radio device and a radio base station, a radio transmitting circuit that has a transmitting mixer, a synthesizer that applies to the receiving mixer υ of the radio receiving circuit, and a radio A switch circuit is provided for the synthesizer applied to the transmitting mixer of the transmitting circuit, and the output of each applied synthesizer is intermittent, and this intermittent state is synchronized for both transmission and reception, and the same as above is applied to the radio base station communicating with the opposite side. In order to synchronize the intermittent transmission and reception of the mobile radio with that of the mobile radio, and on the receiving side, in order to extract only the signals accommodated in the predetermined time throwers 1 to 1, the radio receiving circuit 13 is opened and received. By storing the demodulated signal in a memory circuit and reading it out at a low speed that is 1/n of the speed recorded in this memory circuit, the baseband signal that is the original signal that has been transmitted is There have been reports of examples of systems that have built systems that enable signal reproduction.

In addition, in Document 2, a study was conducted on adjacent channel interference and co-channel interference, which are problems when applying the TCM (time division time compression multiplexing)-FM method described above to small zones.・The possibility of realizing the system has been shown by appropriately selecting parameters. However, there is a possibility that a radio device that does not belong to the system may tune to the same radio channel and the same time thrower 1 and intercept the communication content, and it is necessary to prevent this from the viewpoint of privacy protection. However, there is nothing known regarding this type of technology.

[Problems to be Solved by the Invention] The system construction examples of Documents 1 and 2 described above describe a method for transmitting a CM (time division time compression multiplexing) signal transmitted from a wireless base station to a large number of mobile wireless devices, and a method for transmitting this signal. However, depending on the disclosed transmission method, when other radios not belonging to the system are in use, There remained a problem to be solved in that it is relatively easy to tune in to radio channels and time slots and listen in on communications.

[Means for solving the problem] When transmitting the 'T'CM signal, the wireless base station retrieves the code from the code storage unit, encrypts the time length of each frame given to the transmission signal according to this, and The present invention provides functions for changing the time length of each time thrower 1 and for instructing the type of code and the method of encryption and decoding to mobile radio devices that communicate face-to-face.

[Effect] [- Because the frame length to be used is changed for each frame, and accordingly, the time length of the temporally divided signals accommodated in each time thrower 1~ is changed for each frame. , it has become possible for TCM signals to have high No. 18 functions equivalent to those of digital signals, so it is possible for systems that do not know the order in which the time lengths of the signals accommodated in time throwers 1 to 1 to be given. It has become extremely difficult for a third party's wireless device to listen in, making it possible to ensure the privacy of communications.

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

In FIG. 1A, 10 is a general telephone network, and 20 is a gateway exchange for connecting the telephone network 10 and a wireless system. 30 is a wireless base station and a barrier switch 20
It includes an interface with the mobile radio, a circuit that converts the signal speed, a circuit that allocates and selects time slots, a control unit, etc.
00(100-1 to 10C)-n> and has a wireless transmitting/receiving circuit for transmitting and receiving wireless signals.

Here, between the barrier switch 20 and the wireless base station 30,
There is a transmission line through which communication signals 22-1 to 22n including communication signals of communication channels CH1 to CI-1n and control signals are transmitted.

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

Received transmission signals such as control signals and call signals received by the antenna section enter a radio reception circuit 135 that includes a reception miku'j 136 and a reception section 137, and the output communication signal is sent to a speed restoration circuit 138 and a control section. 140 and clock regenerator 141
is input.

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 darkening 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. Get,
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. Regarding cryptographic information, there is a cryptographic storage unit 177 that stores, for example, a random number table, and this and the control unit 140 further exchange information.

Furthermore, the encryption storage section 177 is used when the mobile radio device 100 takes the lead in encrypting communications.

The communication signal output from the telephone unit 101 is input to the encrypted time frame 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.

Now, the code transmitted as a control signal from the wireless base station 30 is decoded by the decryptor 175, and the result is reported to the control unit 140. Using this, the control unit 14.0 stops the time frame of the telephone signal at the time interval and timing instructed to the encrypted time frame signal forming circuit 178, 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 14.0, the transmission/reception intermittent controller 123.0 is activated. Speed conversion circuit 131.
It supplies necessary timing to the encrypted time frame signal forming circuit 178, the encrypted time piece signal decoding circuit 179, and the speed restoration circuit 138.

For mobile radio Ia100, Zarani Synth 1 noiser 121
-1 and 121-2, and selector switch 122-1.1
22-2, a transmission/reception intermittent controller 123 and a timing generator 142 that generate signals for switching the changeover switches 122-1 and 122-2, respectively.
The synth 4 noiser 1211.121-2, the transmission/reception intermittent controller 123, and the timing generator 142 are the control unit 14.0.
controlled by. Each synthesizer 121-1,
121-2 is supplied with a reference frequency from the reference crystal oscillator 120.

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 line.

Now, the communication signal 22- sent from the barrier switch 20
1 to 22-n are manually input to the signal processing unit 31 of the wireless base station 30. The signal processing section 31 is equipped with an amplifier for compensating for transmission loss, and also performs so-called 2-wire to 4-wire conversion. That is, the input signal and the output signal are mixed and separated, and the input signal from the barrier switch 20 is sent to the encoded time piece signal forming circuit group 78 including the B9 encoded time piece signal forming circuits 78-1 to 78-n. After the signal is converted into the No. 88 signal, it is sent to the signal speed conversion circuit group 51.

The output signal from the signal speed restoration circuit group 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 the signal processing section 31. The signal is then sent to the barrier switch 20 using the same transmission path as the human signal. Of the above, barrier exchange 81
The input signal from 20 is sent to the encrypted time piece signal forming circuit group 78.
and is divided into time intervals according to the instructions of the code generator 76.

Next, this output is sent to many signal speed conversion circuits 511 to 51.
-n is input to the signal speed conversion circuit group 51, and undergoes predetermined speed (pitch) conversion.

In addition, the signal transmitted from the wireless base station 30 to the gateway exchange 20 is outputted from the wireless receiving circuit 35 via the signal selection circuit 39 to the signal speed restoration circuit group 38, where the signal speed (pitch) is converted. The signal is input to the Sho code time piece signal decoding circuit group 79. In this circuit, telephone signals are reproduced and input into the signal processing section 31 as a result of dividing the telephone signals into time intervals according to instructions from the decryptor 75.

Next, the operations of the encrypted time piece signal forming circuit group 7B and the signal speed converting circuit group 51 are explained in FIGS. 2A-1 and 28-2.
This will be explained in detail using figures.

FIG. 2Δ-1 shows the No. 88 time piece signal forming circuit group 78 shown in FIG. 1C. Among the signal speed conversion circuit group 51 and signal allocation circuit group 52, an encrypted time piece signal forming circuit 78-1 for communication channel number 1 is a signal speed conversion circuit 51-1.
Only the signal allocation circuit 52-1 is selected, and similar operations are performed for the communication channel numbers 2 to n, so the 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 left side, Figure 2A2 (a)
A series of telephone signals from the signal processing section 31 enters the encrypted time piece signal forming circuit 78-1. The encrypted time piece signal forming circuit 78-1 is a kind of switch circuit as shown in FIG. Whether or not the robot is turned to the side is controlled by the output signal of the coder 76, including the length of time. Therefore, the series of telephone signals is 2
After being divided, the lf1 piece signal exists on the 78-1-1 side, or the lf1 piece signal exists on the 78-1-1 side, as shown in FIG.
Either exists on the 8-1-2 side, and
Both cannot exist together.

Here, in the telephone signal or encrypted time piece signal forming circuit 78-1 of FIG. 2A-2(a), as shown in FIG. An example is shown in which a random time piece signal follows the output signal. However, in general, the ratio does not necessarily have to be 2:1, and may be e:m (41m is an integer, ri>m).

Now, the signal shown in FIG. 5(b) is input to the signal speed converter 511-1 or 51-1-2 and undergoes speed conversion. The outputs of these two circuits are respectively signal 83'
II is guided to the corresponding unit 52-1-1 or 52-1-2. The signal allocator 52-11.52-1-2 is a type of variable delay circuit, and determines the time slot arrangement of the TCM telephone signal installed within one frame.
The time length of the frame is changed to the value specified by the No. 18 adder 76. The storage/readout circuit of FIG. 2A-1 has a function of once storing the human input signal and then reading it out, and also has the function of reading out the human input signal once τ1. τ2
shows a variable delay time circuit, which makes it possible to perform the operations described above.

Now, the output of this signal S'J circuit 52-1 is mixed and sent to the wireless transmission circuit 32 as shown in FIG. 2A-2 (d>).

Next, the processing status of the output signal of the radio reception circuit 35 received by the signal selection circuit group 39, the signal speed restoration circuit group 38, and the encrypted time piece signal decoding circuit group 79 is shown in FIGS. 2B-1 and 2B-2. This will be explained in detail with reference to the drawings.

FIG. 2B-1 shows the signal selection circuit 39-1 and signal speed for communication channel number 1 among the signal selection circuit group 39, signal speed restoration circuit group 38, and encrypted time piece signal decoding circuit group 79 in FIG. 1C. Only the restoration circuit 38-1 and the 18 coded time piece signal decoding circuit 791 are selected,
Since similar operations are performed for communication channel numbers 2 to n, communication channel number 1 is used as a representative. 2nd B
FIG. 2 is a schematic diagram showing the signal processing state of each part of the circuit shown in FIG. 2B-1.

Now, whether the received signal is selected from the radio reception circuit 35 or the signal selection circuit 3
9 is input. The circuit is a kind of switch circuit,
Using the 88 decoding signal from the decryptor 75 and the timing signal from the timing generation circuit 42, the compressed and time-distorted telephone signal in each frame is selected for each telephone channel, and the signal speed restoration circuit 38- Send it to 1st prize. At this time, since the time length of each frame differs from frame to frame, this information is obtained from the decryption signal that is the output of the decryptor 75, and the timing of the switch position is changed for each frame, and the signal speed is changed for each frame. Restoration circuit 38-1
It becomes possible to send signals to etc.

Next, at a3 in Figures 2B-1 and 2B-2,
The output of the signal selection circuit 39-1 shown in FIG. 2B-2(a) is transmitted from the right side of FIG. 2B-1 to the 8-speed restoration circuit 3B-1.
to human power. The signal speed restoration circuit 38-1 is connected to the second B-1
As shown in the figure, a type of switch 48-1 and a memory circuit 38
-1-1 to 381-3, and is switched to the switch 48-1 or 48-1-1 installed on the input side, or switched to the 48-1-2 or 48-1-3 side. The timing signal is obtained from the timing generation circuit 42 and is performed cyclically in synchronization with the time slot within the frame. The number of signals divided by this switch 48-1 is related to the maximum and minimum time length of the encrypted time piece signal, and in the case shown, the ratio of the time length of the signal to the encrypted time is 2. Therefore, it is divided into three parts. Generally, when this ratio is p>1, the number of divisions is I)+1 if p is an integer, and if p or a number below the decimal point is included, it is given as an integer obtained by rounding all of these up.

Switches shown in FIGS. 2B-1(a)/! 18-1, the time-compressed time segment signal is divided into three parts as shown in FIG. 2B-2(b), and the signal speed restorer 3
8-1-1 to 38-1-3, time expansion is applied to each signal here, and the state before the signal is restored is reached as shown in FIG. 2B-2(C). However, if this continues, the original signal will not be restored, as shown in Figure 2B-2 (C
), the restoration times of time-piece signals vary, and if they are mixed as is, some time-piece signals will overlap, and some time-piece signals will have an instantaneous interruption time when no signal exists. This is because it contains

To recover a continuous audio signal from among the above signals,
It requires the No. 18 decoding signal from the No. 08 decoder 75 and the timing signal from the timing generation circuit 42, and according to these signals, a delay time is given to the signal time piece, and the signal is changed to a signal without overlap and without instantaneous interruption time. Is there a need to do that? Therefore, the encrypted time piece signal decoder 79-1-1
~79-13, the signal time piece is restored to the same length as the time of transmission) '1, and the time piece signal as shown in Figure 2B-2(d) is faithfully reproduced, and the sum of these signals is is sent to the processing unit 31 as a series of telephone signals.

Now, the control of the radio reception circuit 35 or the output of the call signal is performed by the signal selection circuit 3 which separately selects the signal to the time thrower l.
The signal is inputted to a signal selection circuit group 39 including 9-1 to 39-n, where it is separated into speech signals corresponding to each speech channel C1-11 to CI-1n. After this output is restored to a signal speed (pitch) by a signal speed restoration circuit 38 including signal speed restoration circuits 3B-1 to 38-n provided for each channel, the signal processing section Input to 31, 4 wire-2
After undergoing line conversion, this output is sent to the barrier switch 20 as communication signals 22-1 to 22-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 conversations can be used (References: Koita et al. ``A tape recorder that compresses/expands the time axis'' (Nikkei Electronics, July 26, 1976, pp. 92-133).

The circuit using a CCD 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 document, and in this case, [, Jl, clock generator This can be achieved by receiving a timing signal from a timing generator 42 that generates timing using a clock from 41 and a control signal from the control unit 40, thereby making the reading speed slower than the writing speed.

Control or audio signals output from the barrier switch 20 via the signal processing section 31 are input to the signal speed conversion circuit group 51, where speed (pitch) conversion processing is performed and the signals are converted for each time slot. The signal is applied to the signal assignment circuit group 52 for assignment. The signal allocation circuit group 52 is a buffer memory circuit that stores one section of high-speed signals output from the signal speed conversion circuit group 51, and receives timing information from the timing generation circuit 42 given by instructions from the control section 40. Then, the signal in the buffer memory is read out and transmitted to the wireless transmission circuit 32. As a result, when viewed in terms of channel correspondence, the same communication signals are arranged in series without overlapping in chronological order, and when all control signals or speech signals described later are implemented, they appear as if they were continuous. It becomes like a signal wave.

The state of this compressed signal is shown in FIG. 2C-1 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. FIG. 2C-1(a) shows super frames SF1. SF2. . . . and each frame F11 . F12. ..., F21. F
22. Indicates the relationship with... super frame SF1
has one frame F11. F12. ..., Fll, and the time length of these discussions is equal to the time length of the next superframe SF2. Also, each frame “11
°F12. . . , Fll generally differ, and are determined by the signal from the coder 76. For example, the signal from the encryptor 76 can be converted to a decimal voltage (
mV unit), the final value is 5, the Naraha frame length is 1Q m sec, 4.3.2. If 1°0, 9.8.7, 6, 5. msec.

6, 7.8.9. Then 11.12.13.14m s
ec, and if a superframe is formed using i frames, the time length of one superframe is approximately (10x
i) It will be about m sec. Do this exactly (
10Xi) msec, for example, use the last two frames as frames for time adjustment, and
Regardless of the output from the tj unit 76, a frame time length may be given to make the superframe length (10xi) msec.

Also, the first time slot S of each superframe
DO is always used for control signals. This signal is for frame synchronization and a code signal for the mobile radio 14100, and the feature of this signal is that the superframe length is always constant, so that it can be easily captured by the mobile radio 100.

Therefore, the mobile radio device 100 can synchronize and decode the encrypted signal.

Next, in Fig. 2C-1 (b) and (C), the wireless base station 3
1 shows the arrangement of time throwers 1 to 1 in each frame transmitted from the wireless transmission circuit 32 of No. 0.

Here frame F1. F2. F3 is, for example, the same figure (a
> frame F11. “12. Showing Fl3.

In the same figure (b), the time stored in each frame is
It shows that the time length of a slot is given by a value proportional to the length of each frame, and in the same figure (C), for m-1 time throwers from l-S Dl to SDm-1, each frame The remaining n-(m
1), an example is shown in which they are shortened or expanded in accordance with each frame length. However, the guard time between time slots was kept constant for all frames in (b) and (c).

Since encryption is performed regarding the time thrower l~ and the frame time length as explained above, the mobile radio device 100 that receives this signal needs to decode the signal according to the process described above. , the original signal will be reproduced.

In addition, in Figure 2C-1 (b) and (C), F
l is the first frame of frame "1 is superframe S"1. Therefore, an example is shown in which the above-described time thrower l-S DO exclusively for control signals is installed.

Next, a large number of mobile radio devices 100 transmit, and the radio base station 3
The signal received will be explained using FIG. 20-2. Figures 2C-2 (a) and (b) are similar to Figure 2C-1 (b).
), (C)
0-=wireless base station 30) This is an example of the signal g, and each mobile wireless device 100 receives the dark bow sent from the wireless base station 30 by M.
The example is shown in which a signal transmitted from the mobile radio device 100 is input to the radio receiving circuit 35 according to the time slot number, timing, and time length of the time segment that are instructed. In the same figure (Puruflame F1.F2
．． ...and time slot SUO.

SUl, SU2. 11) The distance between frames F1 and F2° in the second (, -1 Figures (b) and (C), respectively) is
・SD○, SDl, SD2゜ to Yatime Thrower 1・
It is the same as...etc. However, the first time slot SUO of frame "1" is for a specific mobile radio device 100 to transmit a control signal addressed to the radio base station 30 when making a call, etc., and is always left unused. This indicates that a large number of mobile wireless devices 100 are used for time sharing.The time length of this time slot SUO is always constant regardless of the frame length F1.

The time length of each frame or time slot in Figure 2C-2 is the same as that in the corresponding Figure 2C-1.

Note that the first time thrower 1 to SDO of each frame accommodates frame synchronization and control signals, and the time slots SD1 to SD3[)n accommodate the mobile radio device 100.
A call signal and/or a control signal in response to an incoming call to or an outgoing call from the mobile radio 100 is accommodated. If a speech signal is not implemented, the speech signal portion may be supplemented with an empty slot signal or, depending on the system, may have no signal transmitted at all, including the carrier wave.

In this way, as shown in FIGS. 2C-1 (b) and (C), in the radio transmitter circuit 32, signals forming one lumen are applied to the modulation circuit in the time slots SDO, SD1 to SDn. become. The time-series multiplexed signal to be transmitted is angle-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 described above, the control signal transmission between the mobile radio device 100 and the mobile radio device 100 is carried out using time slot SDO, but depending on the system, it is possible to use either within the telephone signal band or outside the telephone signal band. It is also possible.

Figure 3A shows these frequency relationships. In other words, in the figure (a), it is an example of an out-of-band signal, and as shown in the figure,
Low frequency side (250Hz >) and high frequency side (38501-1
2> 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.

The above examples were all tone signals, but it is possible to transmit many types of signals at high speed by increasing the number of Hoehn signals or modulating 1 to - to create a subcarrier signal. becomes.

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. The audio signal and the control signal can be extracted separately by receiving the signal with the opposing receiver and performing the operation in the demodulation circuit in the opposite manner to that shown in FIG. 3C.

On the other hand, the signal sent from the mobile radio device 100 is received by the antenna section of the radio base station 30, and is received by the radio receiving circuit 35.
is input to. FIG. 2C-2 schematically shows this upstream input signal.

That is, each frame F1. F2. F3. ... time slot SU1. S[J2. ..., 3Un are mobile radio devices 100-1. 'too~2. ..., 100n
3 shows a transmission signal addressed to the wireless base station 30 from.

Also, each time slot SU1. SU2. ..., 5I
The contents of Jn consist of speech signals and/or control signals. However, if you want to make a call or emergency communication from the mobile radio [100 to the radio base station 30, t, j:,
The time slot SUO, which is always placed at the beginning of each frame, is used.

Now, among the input signals that have arrived at the radio base 830, the control signal is immediately sent to the control unit 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 output of the signal speed restoration circuit group 38 to the control unit 40 after performing similar processing on the call signal. Further, the call signal is applied to the signal selection circuit group 39.

A timing signal from a timing generation circuit 42 that generates a predetermined timing is applied to the signal selection circuit group 39 according to a control signal instruction from the control section 40, and a timing signal is applied to each time thrower l-3U1 to Sun. A synchronization signal, a control signal, or a speech signal is separated and output. Each of these signals is input to the signal speed restoration circuit group 38, and as described above in detail, the signals are transmitted to the mobile radio device 100 on the transmitting side.
It has a function of performing inverse conversion of the speed conversion circuit 131 (FIG. 1B) that is applied to the speed conversion circuit 131 (FIG. 1B), whereby the original signal is faithfully reproduced and transmitted to the gateway exchange 20.

The mode of transmission in the 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 group 52. 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.

The original signal, for example, an audio signal (0.3 kl-(Z ~ 3.0
FIG. 3B shows the frequency distribution on the output side when the signal speed conversion circuit group 51 (FIG. 1C) passes through the signal speed conversion circuit group 51 (FIG. 1C). In other words, as mentioned above, if the audio signal is 15
If converted by a factor of 2, the signal frequency IE has been expanded to <4.5kl-Iz~/15kt(z) in FIG. 3B.

Here, the signal is expanded by the frequency of the signal, but it is necessary to keep in mind that the waveform form is simply a stretch of the frequency axis, and the waveform itself remains unchanged. Also, for signal encryption, the time length of the time piece signal is different for each frame, but in order to perform compression proportional to the time length of the signal during time compression, it is accommodated in each time thrower 1. The highest frequencies of the signals do not differ. Now, FIG. 3B shows a case where the control signal is simultaneously transmitted using the lower frequency band of the audio signal. Among these signals, the control signal (0, 2-4, 0kt-1z
, ) and a call gCH1 (denoted as SDI with 4,5 to 45kl-12) are accommodated in a time slot, e.g. SDI. The same applies to the audio signals accommodated in the other time slots SD2 to SDn.

That is, time slot soi <r=2゜3, -
, n> has a control unit @ (0,2~4.0kl-1z>
and communication signal Cl-1i (4,5~45kt-+Z)
is accommodated. However, the signals within each time slot are arranged in chronological order, and multiple time slots are
The signals in slots 1 to 1 are never 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 angular modulator included in the If there are multiple radio channels, the speedup of the signal by the signal speed conversion circuit group 51 is limited to a certain number due to the limitations on these frequency intervals.
rep and the maximum signal speed due to the above-mentioned speed increase of the audio signal is fN, then the following inequality must hold between the two.

f > 2 f u ep On the other hand, in digital signals, audio is usually digitized at a speed of about 64 kb/s, so read by raising the scale on the horizontal axis in Figure 3B, which explains the case of analog signals, by about one digit. Although necessary, 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 (conversion 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. It is sent to the barrier exchange 20.

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.

When the mobile radio device 100 is powered on, the first
In the wireless receiving circuit 135 in Figure B, the downlink (wireless base station 30
→Mobile radio 100) Wireless channel (Channel C111)
start capturing the control signals contained in the If the system is provided with multiple radio channels, the radio channel with the highest received input field)
Radio channels instructed by control signals included in the radio channel: i) Channels with empty time slots among the time slots in the radio channel, etc. The channel CHI is in the receiving state for each frame Fl shown in FIGS. 20-1(b) and 20-1(c).

F2. This is possible by capturing the synchronization signal within time slot SDi within -2. 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 also controls the synthesizer 1.
It is in a state where it is tilted to the 21-1 side and fixed. Therefore, when the receiver of the telephone unit 101 is off-hook (starting calling>-y (3201, FIG. 4A)), the synthesizer 1 of FIG.
21-2 receives from the control unit 140 a control signal that generates a local frequency that enables transmission of the wireless channel CH1. Further, the switch 122-2 is also connected to the synthesizer 12.
Fold it to the 1-2 side and it becomes fixed. Next, the calling control signal output from the telephone section 101 is sent out using the wireless channel C)-11.

This control signal is transmitted in the frequency band shown in FIG. 3A (b) using, for example, time slot SUO.

The transmission of this control signal is limited to time slot SUO, and is sent in bursts, and no signal is transmitted during other time periods, so it does not adversely affect other communications. However, if the speed of the control signal is relatively slow or the amount of information in the signal is large and cannot be accommodated in one time slot, the same time slot of the next frame or Sent 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, and by receiving this, the mobile radio 18100
Frame synchronization is possible. This control signal roughly includes:
Contains control information such as currently used time slots and unused time slots (empty time slot display). Depending on the system, the time slot SD
When i (i = 1.2. . . . , n) is used for other communication, it may contain only the synchronization signal and the call signal, but even in such a case, the unused time signal Slots 1 to 1 usually include a synchronization signal and a control signal, and by receiving this control signal, the mobile radio 100 knows which time slot to use to send out a calling signal. I can do it. Note that if all time slots are in use, it is not possible to make a call on this wireless channel and it is necessary to sweep and search for another wireless channel.

In other systems, empty slots may not be displayed 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, which has received the control information sent from the radio base station 30 by one of the above methods, determines in which time slot it should send the call control signal. It is too difficult to judge including the transmission timing.

Furthermore, the system led by the radio base 830 encrypts the communication signal.At this point, the mobile radio 100 has received the encryption information, and once communication starts, the control unit 1
40 can enter a standby state for a code to be given to the encrypted time piece signal forming circuit 17B. However, confidential conversations will not be made until the call has started.

Assuming that the time slot SUO for uplink signals is an empty slot (...), we will use this empty time slot, send out a control signal for calling, and calculate the necessary timing from the response signal from the wireless base station 30. It is possible to take out the control signal and send out a burst control signal.

If there is a call from another mobile radio at the same time, the calling 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 call collisions are to be significantly reduced, the following method may be used. If the mobile radio 1100 finds an empty time slot in which it can make a call, it does not use the entire time slot, but uses only the first half for some mobile radios and the latter half for others. This is the way to do 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 slot within that one time slot. This is a method of giving a belt. 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, assuming that the call control signal from the mobile radio Ia 100 is successfully received by the radio base station 30 and the ID (identification number) of the mobile radio 100 is detected (8202), the control unit 40 of the radio base station 30: To detect the ID (identification signal) of the mobile radio 100 (3202) and confirm the ID, the communication channel designation signal and encryption information necessary for making a call are sent to the mobile radio 100 in the downstream time slot S.
Transmit to the mobile radio device 100 using DO (8203
>.

The mobile radio 81100 that has received the control information sent from the radio base E30 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 3.
0 (S205>) and waits for dial numbers 1 to -- to be sent (3206>).

The radio base station 30 naturally expects this and is waiting for reception, and upon receiving the slot switching completion report (8207>
, 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 switch groups included in the barrier exchange 120. The dial number is sent to the wireless base station 30 (3210, 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 a communication path has been set (3212>). Time mobile radio 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
The dial signal is transmitted using the uplink time throwers 1 to SU1 (S213>).The thus transmitted dial signal is received by the radio receiving circuit 35 of the radio base station 30. responds to the calling signal from the mobile radio device 100, gives the time thrower 1 to be used, operates the signal selection circuit group 39 and the signal allocation circuit group 52 of the radio base station 30, and adjusts the uplink time. - Receive slot SU1 and receive downlink time slot SD1
It is now in a state where it is transmitting a signal. Therefore, the dial signal transmitted from the mobile radio 100 passes through the signal selection circuit 39-1 of the signal selection circuit group 39, and then passes through the signal speed restoration circuit group 38 to the encrypted time piece signal decoding circuit group 79. 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.

In the mobile radio device 100, the signal waiting for reception is received by the radio reception circuit 135 in the time thrower of the radio channel CI-11 to SDI, and its output is inputted to the speed restoration circuit 138. In this circuit d3, the original signal of the transmission is restored and inputted to the handset of the telephone section 101. A call will be started between the Hidden-C1 mobile radio 100 and a general type telephone within the general telephone network 10 (S2
16>,.

Furthermore, as described above, the wireless base station 30 and the mobile wireless device 100 are already prepared for the secret conversation, and once the conversation starts, it is immediately executed.

To do this, the control section 40 may give a control signal to the code input device 76 to start its operation at the same time as the start of the call.

In addition, is it possible to use confidential communication even in control communication between the radio base station 30 and the mobile radio device 100, which is performed before the start of a call, such as the above-mentioned call channel assignment?
I omitted the explanation because it is not very practical.

The call is terminated by turning on the receiver of the telephone unit 101 of the mobile radio device 100 (3217>), and the end of the call signal and the on-hook signal from the control unit 140 are transmitted to the speed conversion circuit 1.
31 from the wireless transmission circuit 132 to the wireless base station 30 (3218>), and the control unit 140 stops the operation of the transmission/reception intermittent controller 123 and switches 1221 and 122-2 to the synthesizer 1.
It is fixed to the output ends of 21-1 and 121-2.

On the other hand, in the control unit 40 of the radio base station 30, the mobile radio device 1
When the call termination signal is received from 00, the call termination signal is forwarded to the barrier switch 20. 3219>, switch group (not shown)
The switch is turned off to end the call (S220>. At the same time, the signal selection circuit group 39 and signal allocation circuit group 52 in the wireless base station 30 are opened.

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

(2) Incoming call to mobile radio device 100 The mobile radio device 100 is on standby with the power turned on. In this case, as explained in the section regarding the call origination from the mobile radio [100], the mobile radio [100] is in a waiting state to receive a downlink control signal from the wireless channel C111 according to 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 switch 20. These control signals pass through the signal processing section 31, the encrypted time frame signal forming circuit group 7B, and the signal speed conversion circuit group 51 as communication signals 22, and are sent to the control section 40 via the signal allocation circuit group 52, in the same way as audio signals. (Figure 1C).

Then, the control unit 40 selects the wireless channel A addressed to the mobile radio B1100.
Empty slots behind the downlink time slots of Channel CI-II, for example, using SDI for mobile radio 14100
The mobile radio 100 transmits an ID signal, an incoming call signal display signal, a time slot usage signal (for example, SUL corresponding to SDI is used for transmission from the mobile radio device 100). In the mobile radio device 100 that received this signal, the radio receiving circuit 13
5 is transmitted to the control unit 140 from the receiving unit 137. 11
7111 section 140 transmits this signal to its own mobile radio device 1.
To confirm that it is an incoming call signal to 00, telephone section 1
01 J = At the same time, the transmission/reception intermittent controller 123 is operated to stand by at the designated time slot SDI, SU1, and switch 1 is activated.
221.122-2 starts turning on and off. In this way, the state of being able to make phone calls has been transferred.

Note that it is clear that confidential communication can be performed for incoming calls as well as for outgoing calls. Furthermore, it is clear that the confidential conversation technology described in the present invention makes it extremely difficult for a third party who does not belong to the system to listen in without permission.

This is because the time length of frames and time slots used for communication differs from frame to frame, and even if a signal for a certain time slot can be received, the exact time length is not known and the next frame Since I don't know the length of the broadcast, a large amount of noise comes in, making it impossible to listen.

[Effects of the Invention] As is clear from the above explanation, the secret method regarding the CM signal, which has not been disclosed in the past, has become practical, making it difficult for a third party's radio equipment not belonging to the system to overhear it. , the effect of ensuring 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. A circuit configuration diagram of the station, FIG. 2A-1 shows the internal configuration of the encrypted time piece signal forming circuit, signal rate conversion circuit, and signal allocation circuit, which are the components of FIG. 1C. Figure 2 is 2A-
Time chart 1 showing the signals of each part of the circuit shown in Figure 1
~, Figure 2B-1 is a circuit configuration diagram showing the internal configuration of the signal selection circuit, signal rate restoration circuit, and encrypted time piece signal decoding circuit, which are the components of Figure 1C, and Figure 2B-2 is the circuit configuration diagram of Figure 2B-2. 1
2C-1 and 2C-2 are time charts showing the signals of each part of the circuit shown in the figure. 3A and 3B are spectral diagrams showing the spectrum of call signals and control signals; FIG. 3C is a circuit configuration diagram for multiplexing voice signals and data signals; FIGS. 4A and 4B are diagrams of the present invention. Flow charts 1 to 1 show the flow of operation of the system according to the invention. 10... Telephone network 20... Gateway switchboard 22
-1 to 22-n...Communication signal 30...Radio base station 31...Signal processing section 32...Wireless transmitting circuit 35...Radio receiving circuit 3
8...Signal speed restoration circuit group 39...To signal selection circuit 39-1-39-n...Signal selection circuit 40...Control section 41...Clock generator 42...Timing generation circuit 51...Signal speed conversion circuit group 51-1 to 51-n...Signal speed conversion circuit 52...
Signal assignment circuit 75...Code decoder 76...Cipher (=I vaporizer 77...Code storage unit 78...-18g conversion port, 1 piece signal forming circuit group 79...
- Encrypted time piece signal decoding circuit group 91...Digital encoding circuit 92...Multiple conversion circuit 100.100-1 to 100-n-...Mobile radio device 10
1...Telephone unit 120...Reference crystal oscillator 121-1, 121-2...Synthesizer 122-
1,122-2...Switch 123...Transmission/reception intermittent controller 131...Speed conversion circuit 132...Wireless transmission circuit 133...Transmission mixer 1
34... Transmission section 135... Radio receiving circuit 1
36... Reception mixer 137... Receiving section 138.
... Speed restoration circuit 141 ... Clock regenerator 175
...Code decoder 177...Code storage section 178.
...Encrypted time piece signal forming circuit 179... Encrypted time piece signal decoding circuit. Agents 1) Kosan (1 idiot) Figure 1A 100-n

Claims (1)

[Scope of Claims] Each radio base means (30) each covers a plurality of zones and constitutes a service area, and a frame for moving across the plurality of zones and communicating with the radio base means. mobile using barrier exchange means (20) for exchanging communications between each mobile radio means (100) using a radio channel carrying time-compressed delimited signals in the time slots of the configuration; In the physical communication method, when creating the temporally compressed delimited signals to be accommodated in time slots in frames that communicate oppositely, the time lengths of each frame containing the delimited signals are made to be opposite to each other. A time-division communication secret method for mobile communication defined in the wireless base means communicating with each other.