JPS5923501B2 - Mobile communication method - Google Patents

Abstract

PURPOSE:To facilitate an easy setting of the random number between the mobile stations by adding the random number decision function to the mobile communication system. CONSTITUTION:The analog signal 1 which is the original information is applied to A/D converter 2, and this output is sent to circuit 3 which carries out the code processing with the fixed timing clock. And the output of circuit 3 is applied to synchronous signal addition device 4, and the synchronous signal is added by insertion before the digital signal of each frame. Then the output is sent to the random number addition device consisting of devices 5a and 5 to be applied by the random numbers for secrecy. After this, the output applied by the random numbers is modulated at modulator circuit 6 to be transmitted from antenna AT via transmission part 7. This output is received at antena AR at the reception side, demodulated by demodulator 9 via reception part 8, and translated via random number translators 10 and 10a to undergo the synchronous check through random number synchronous check circuit 11. Then the synchronous setting is given at synchronous circuit 12 to obtain analog signal 15 which is restored via code process circuit 13 and D/A converter 14.

Description

[Detailed Description of the Invention] The present invention digitizes analog signals such as voice and multiplies them with random numbers for secrecy in wireless communication lines where good transmission quality is often not obtained, such as shortwave lines. The present invention relates to a mobile communication system that can easily set up random number synchronization when transmitting digital codes between mobile stations located in a wide area.

Conventionally, when transmitting digital codes between mobile stations by multiplying random numbers after digitizing an analog signal, the mobile station sets random number synchronization using a random number digital signal transmitted from a fixed station for a certain period of time. Even when mobile stations perform mutual transmission and reception, if one mobile station loses random number synchronization, it becomes impossible for that mobile station to transmit digital codes, and if there are many mobile stations that lose random number synchronization, the system of the present invention Since the system does not have a random number determination function, it is difficult to determine which mobile station has lost its random number synchronization.

Even if I tried to set the correct random number synchronization again, I was unable to communicate with the other station until the next digital signal was sent from the fixed station. Even if a mobile station that attempts to join this communication network later tries to perform transmission/reception with multiple mobile stations that have already been synchronized with random numbers by setting the random number synchronization correctly, it will not be possible to set up the correct random number synchronization from the fixed station. A certain amount of time was required until the random number digital code transmission was received. On the other hand, even if random number synchronization is applied to a mobile station that is thought to have already been set up for random number synchronization, this does not necessarily mean that the mobile station has set up the random number synchronization correctly, making it difficult to construct a wide area communication network. The present invention overcomes these drawbacks and will be described in detail below. Figure 1 is a configuration example diagram of a transmitting device embodying the present invention, which converts an analog signal of original information into a digital signal, then multiplies it with a random number for secrecy and transmits it over a wireless line. .

This transmitting device (well, in general, the fixed station and mobile station can be considered to have the same circuit configuration, just that the fixed station has higher transmission power.
FIG. 2 is a configuration example diagram of a receiving device embodying the present invention, which is a device that translates a random number digital signal received over a wireless line after synchronizing the random number with the transmitting station, and converts the digital signal into an analog signal.

This device is equipped with a circuit (RTEST) that checks whether the random number synchronization of the own station has shifted during reception after synchronizing the random numbers using a random number digital signal transmitted from the fixed station.
l). 3 and 4 are diagrams showing an example of the configuration of a communication network in which the present invention is implemented, and FIGS. 5 and 6 are diagrams showing an example of operation waveforms of each part in FIGS. 1 and 2, respectively.

Note that FIGS. 7 to 10 will be explained later. First, the operation on the transmitting side will be explained mainly with reference to FIGS. 1 and 5. In FIG. 1, an analog signal 1, which is original information, is input to an analog-digital converter (A/D) 2 and converted into a digital signal. This conversion can be done by digitizing the analog signal using optimal parameters for restoring it to an analog signal on the receiving side, but for example, the analog signal of the T waveform shown in FIG. There is a method of converting the signal into a digital signal using the level (or frequency, etc.) as a parameter by dividing the signal into small time intervals. A
The output of /D is input to DTl in 3.I) T1 is a circuit that encodes the digital signal using a timing clock, and the bit length of 1 word or 1 frame is determined in advance to be the same between the transmitting and receiving stations. The digital signals for each frame are serially divided into 2, such as 101001...
The signals are arranged in order according to the base code and sent to the next stage 4 (STl). Figure 5 2-T waveform is this output waveform, Sl, S2,...S
Each of O, SO+1, . . . is a serial digital signal for each frame. 4 (STl) is a synchronization signal adding device whose purpose is to synchronize the frame synchronization of digital signals of transmitting and receiving stations (bit synchronization can also be achieved by synchronizing frames at regular intervals) When a control signal is applied to each frame, a synchronizing signal N is inserted and added before the digital signals Sl, S2, etc. of each frame.

The 3-T waveform in FIG. 5 is a waveform to which the synchronization signal N for each frame is added. In this example, N has a 5-bit configuration and 1
0110 is used. The output of this STl is 5 CPT
It is sent to a random number addition device consisting of CTl (control circuit) 1 and 5a, where it is multiplied by a random number for secrecy. The 4-T waveform in FIG. 5 is the output waveform multiplied by this random number. The random number synchronization code is always changed at the N position, but there is no increase or decrease in bits.N(101,10) is transmitted like a 4-T waveform, according to the random number convention predetermined between the receiving stations. Nxl (10001), Nx2 (10101), N
x3(00010),...NXITl(010
10), NXIm+1 (00111), and so on. Note that there are 25=32 types of random number synchronization codes in a 5-bit configuration, some of which are shown in FIG. Furthermore, even when these random number synchronization codes are used, depending on the order in which they are combined, there are a total of (25) combinations of random number synchronization! There are =2.6313083×1035 ways. In order to transmit digital codes between the sending and receiving stations, the number of these 32 types of random number synchronization codes to be used and the order in which they will be sent out in circulation should be determined in advance, and 5a( The digital switches A and B shown in FIG. 8, which are provided at CTl) and 10a (CRl) in the random number translation device on the receiving side, are set in the same way.

Furthermore, in the above example (Fig. 5-4-T), the random number synchronization code is changed at the N position once per frame, and the digital information is changed correspondingly, that is, multiplied by a random number. A combination of changing the random number synchronization code once every frame is also possible. Now, the random number addition device 5 in Figure 1
, 5a, the output of the 4-T waveform in FIG. 5, which has been multiplied by random numbers according to the rule settings of digital switches A and B in FIG. is modulated with a 4-T waveform in an appropriate modulation format, and transmitted from the transmitter T of 7 through the antenna AT over a wireless line.

Here, a method for forming a communication network according to the method of the present invention when transmitting and receiving the above-mentioned random number digital signal over a wireless line will be explained.

FIGS. 3 and 4 are examples of the communication network, and A1 in FIG. 3 is a fixed station, and Bl, B2, Cl, C2, and Dl are mobile stations. Mobile stations other than D1 receive random number digital signals from fixed station A1 and are synchronized with random numbers, allowing mutual transmission and reception between these mobile stations, while mobile station D1 is not yet synchronized with random numbers, but according to the present invention. It is assumed that the mobile stations B1, B2, etc., which have completed random number synchronization by performing the above steps, are attempting to interrupt the communication network and perform transmission and reception with other mobile stations by performing random number synchronization. Therefore, next, a method will be described in which fixed station A1 first starts transmitting, then mobile stations B1 and B2 start receiving, and then synchronize with random numbers to A1. Fixed station A1 to 5th
When the random number digital signal of FIG. 4-T is transmitted at frequency f1 for a certain period of time, each mobile station of B1 and B2 of FIG. 3 receives it via the receiving antenna AR of FIG. It is assumed that the operation is performed at the position S in the time-operation characteristic diagram indicated by -R.

In the receiving section 8 of FIG. 2, the f1 wave is selectively extracted and amplified, and then demodulated by the demodulator (DEMl) 9, the random number digital signal of the 2-R waveform of FIG.
l) Enter 10+10a. Note that CPRl can be said to be a random number translation circuit, and CRl can be said to be its control circuit. At this time, the random number translation device cannot perform translation because it is not synchronized with the transmitting station. Therefore, it is impossible to synchronize the frame before multiplying the random number with that of the transmitting station, and the analog signal cannot be restored. However, Fig. 6 1-2-R after the ROS point
When the first bit a of the waveform is input, the received code of the previous five bits including this a is checked by CPRl. In this case, since there is no receiver power before S, all the previous bits of a are 00000 with 60° in binary code. If this a
The bit position is the random number synchronization code Nxm (m=1, 2, 3,
...N, n+1, ...), it is 00000 (1) in the random number synchronization code in Fig. 7, so the next bit is determined by the settings of digital switches A and B in Fig. 8. The receiving station can predict which random number synchronization code will arrive. In other words, since the bit length up to the same position among the 5 bits of the next predicted random number synchronization signal for bit a in FIG. 6 is 1 in FIG. 6 2-R, at least this 1
The bit length data is stored in 10 (CPRl) in FIG. 2, and the previous five bits including the 2-ROf bit in FIG. 6 are checked. In the example of FIG. 6, this is 10010 (bit f at the end).

Set this in advance to digital switches A and B (Fig. 8).
If the random number synchronization code set in and the arrival rule (order of arrival) are different, it means that the position of the a bit is not the break point of random number synchronization. Note that such an operation requires that the test be completed before the next g bits of f are received. Next, for the b bit, the previous 5 bits including b are similarly checked (in this case, they are 00001), and the same random number synchronization judgment as a is performed for the bit length of 2 for b. In this way, random number synchronization determination is performed for each bit of C, d, and e as well for bit lengths of 3, 4, and 5. For example, for the e bit, if you check the previous 5 bits including this, it will be 01010 (Abcde).On the other hand, with a bit length of 5, the next random number synchronization code will be 0001.
0 (Fghij), and if this matches the random number synchronization code arrival rule of the A and B digital switches in FIG. In the example shown in Figure 6, e is Nx2, j is Nx3) Even for the predicted bit length 6 after j bits, the previous 5 bits from the end are checked to determine whether or not it is a random number synchronous code. I do. As described above, if a plurality of consecutive random number synchronization codes (for example, 10 from NX2 to NXll) are checked and they match, for example, 70%, these are considered to be random number synchronization codes, and from the next bit onwards, the The received information digital signal multiplied by random numbers is translated in accordance with the random number rule set by the digital switches A and B in FIG. 8, regardless of the received random number synchronization code.

In other words, once random number synchronization is set, this (discrimination of the break point between the random number synchronization code and digital information is set), but after that, the random number synchronization code may change due to deterioration of the quality of the wireless line, etc. Even if an error occurs, random number translation is performed regardless of this to restore the original digital information.More specifically, random number synchronization is performed for the received signal that arrived at the position t1 of the 3-R waveform in Fig. 6. If it is, then at which bit position the random number synchronization code will arrive is known by the settings of the A and B digital switches provided in the random number translation device, so all the random number synchronization codes are N (in this example 10110) to translate the random number digital signal.

In Figure 6 3-R, the translated digital information is Sn-1
, Sn, Sn+1, . Now the second
In the figure, an output signal as shown in FIG. 6 3-R from the random number translation device is input to the random number synchronization test circuit 12 (SRl) via the random number synchronization test circuit 11 (RTESTl).

12 (SRl) is a circuit that synchronizes the frame and bits of the digital signal using the synchronization code N, and its output is 1.
3 (DRl), where it undergoes code processing such as timing in preparation for restoring it to analog information, and then is sent to the digital-to-analog converter (D/A) 14.

From 14 (D/A), it is almost the same as the sending side. Figure 6 4-R
An analog signal such as is obtained at its output 15.

Note that in shortwave lines and other lines where the receiving electric field fluctuates significantly depending on the distance between transmitting and receiving stations, the frequency used, etc., it is often difficult to set up random number synchronization for all mobile stations with one fixed station.

In such a case, the method of multiplying random numbers is the same and the modulated input signal is supplied from one location, but it is also possible to use a plurality of frequencies and transmission locations for transmission from the fixed station.
For example, three transmitting stations are provided, A, B, and C, and different transmitting frequencies are assigned to them, such as Fl, f2, and f3. If the mobile station receives a signal of the optimum frequency among these transmission waves and performs random number synchronization, it is possible to transmit from the fixed station to the mobile station and to send and receive random number synchronized digital codes between the mobile stations. In this way, for example, the mobile stations C1 and C2 in FIG. 3 can obtain random number synchronization with the fixed station A1, and the mobile stations B1, B2, Cl, and C2 can mutually transmit and receive random number digital signals. By the way, if the random number adding device of the transmitting mobile station (5, 5a in Figure 1)
) Also, (1 receiving side mobile station random number translation device (10 in Figure 2)
, 10a) or a large frequency shift in the crystal oscillator of the local station (not shown, but the oscillator located in the random number adding device and the random number translation device that controls the timing of clock pulses, etc.). If the random number synchronization timing differs from that between the two, mutual communication will become impossible. Moreover, another mobile station (for example, D1) synchronizes the random number synchronization with the mobile station (for example, C2) that has lost this random number synchronization, interrupts this communication network, and transmits and receives random number digital signals between the mobile stations. Even if you try to do so, it is impossible to transmit/receive with other mobile stations B1, B2, and Cl that have correct random number synchronization. If a system is formed, it will cause confusion.In order to prevent such errors, the mobile station should perform random number synchronization and then check the random number synchronization again using the random number digital signal transmitted from the fixed station A1. Only the mobile stations need to apply random numbers so that they can mutually transmit and receive data.Furthermore, if the random numbers are out of synchronization during the test, it is automatically corrected.If a mobile station passes the test, for example, C1 in Figure 3, then Mobile station D desiring random number synchronization interrupt
1. If synchronization is achieved, all mobile stations will not disturb the random number synchronization of the communication network, and even if a mobile station loses random number synchronization, the random number synchronization will be automatically corrected by inspection, allowing stable transmission and reception. can.

Here's how to fix it.

FIG. 10 is a diagram showing an example of random number synchronization test correction, and this figure shows that a random number digital signal different from the random number digital signal initially sent from the fixed station A1 in FIG. 3 to multiple mobile stations to achieve random number synchronization is An explanation will be given as an example of a correction method when an error occurs when the mobile stations Cl and C2 in FIG. 3 receive random number digital signals transmitted at a later agreed time and check the random number synchronization. FIG. 10 shows time distinctions, where A is the transmission stop time of the fixed station A1, and B is the time during which the random number digital signal is being transmitted. The fixed station and the mobile station have the same random number rules set in the A and B digital switches in Figure 8 as described above, and both the transmitting and receiving stations start from S1 in Figure 9 and close to A1. Assume that there is a random number synchronization code position in . FIG. 9 is an explanatory diagram of the movement of random numbers determined between sending and receiving, and the random number synchronization code changes in the determined order of the determined contents.
Although it cycles, the random number pattern of fixed station A1 starts from S1 at a certain time, and the mobile station has the same timing (time adjustment) of its random number addition device or random number translation device as the fixed station, but sets random number synchronization. is slower than that, for example around A1. The waveform in FIG. 10 is the random number digital code being transmitted, and the random number synchronization code Nx8 (101
00), Nx9 (01100), NxlO (01101
), Nxll (00010), Nx,2 (11101)
etc. are transmitted in order according to the transmission protocol. Also SX8,S
X9, SXlO, SXll, . . . are information signals changed from the original digital codes multiplied by random numbers by these random number synchronization codes. In this case, the mobile stations Cl and C2 in FIG. 3 perform their own random number synchronization check at T in FIG.
Let us start from position 1. This random number synchronization check is based on the random number synchronization (sign and order) determined in the same way as the mobile station sets random number synchronization using the random number digital signal transmitted from the first fixed station as explained earlier, and The transmitted random number digital signal is compared with the random number synchronization set, and if it is incorrect, the random number synchronization is corrected to the one at the time of inspection. Specifically, regarding T and subsequent bit a in Figure 10, the first 5 bits (00001) including this bit are checked with the same 1-bit length as in Figure 6, including h, and the digital switch is determined. It is determined whether it matches the random number synchronization code arrival rule determined by A and B (FIG. 8). If they do not match, then perform the same check on each bit B, c, d, e, f, and g in order. For example, if bit g
When the 5-bit Cdefg = 10100 for Jklmn = 01100 is checked with a bit length of 6, it matches the random number synchronization code arrival rule of A and B, and if it also matches with the next bit length of 7, set T2 to the random number at this time. It is determined that this is the break point of digital information multiplied by a synchronization code and a random number. The determined break point of T2 and the previous random number synchronization code Nx9 (01100) are already at the fixed station A1.
If the random number synchronization is determined and matches the breakpoint at which random number translation is performed sequentially according to the random number convention and the random number synchronization code that can be predicted at that time, the mobile station passes the test. For example, mobile station C1 in FIG. 3 is mobile station Sl in FIG.
If random number synchronization was set in advance from the beginning in S2, S3, S4, and S5, the test would pass. The other mobile station C
2, even if the random number synchronization settings are correct at first, the synchronization will go out after that and the Sll re-Sl25Sl39Sl4 in Figure 10 2 will occur.
, Sl5, if random number synchronization had been set, it can be determined that there is a 2-bit shift at time T2, so the 2-bit correction is made here. The mobile station that passes the test, for example C1 in FIG. 3, may then set up random number synchronization for the mobile station D1 that desires a random number synchronization interrupt.

In addition, since the mobile station C2 does not reach the final bit (5th bit) of the random number synchronization code at time T2 in FIG. 10,
This will correct the received random number synchronization code NXlO, and the test will fail with a transmission time of 1, but after a certain period of time, the random number synchronization test will be performed again, and if it passes this test, it will be the same as the C1 mobile station. Random number synchronization may be set for the D1 station.

This test is carried out by the random number synchronization test circuit 11 (RTEST1) shown in FIG. 2, and whether or not the own station has passed the random number synchronization test may be displayed by providing an indicator lamp or the like in this circuit 11. 10. Waveforms 3 and 4 of FIG. 10 show the output digital waveforms of FIG. 2 13 when C1 and C2 in the above example inspect and translate random digital codes, respectively, and C2
The station can output a correct digital signal after the CT shown in FIG. 10, and can correctly maintain frame synchronization with the original digital signal from the transmitting station after the DT. 1st
0 Figures 5 and 6 are Figure 2 1 for each station of Cl and C2, respectively.
This shows the restored analog signal that is the D/A output of station C1.The analog signal of station C1 is almost the same as the original analog signal of fixed station A1, but for station C2, the DT of FIG.
Thereafter, it becomes equal to A1. Furthermore, the method of setting up random number synchronization using the random number digital signals transmitted from B1, B2, and Cl that passed the inspection by the D1 station is exactly the same as the method in which the mobile station initially set up random number synchronization using the signal from the fixed station. . Fig. 4 is a different communication network configuration diagram, but the only difference from Fig. 3 is the configuration method. Initially, the master stations Al, Al2 of the two mobile station groups are set to random number synchronization with the fixed station A1. Only this master station performs a random number synchronization check, and the slave stations belonging to each group, in the example of group A, Bl, B2, B3.
, Cl, and the first group, Dl, D2, and El can perform mutual random number digital code transmission after setting random number synchronization with the parent station of each group. In this way, even if many mobile stations existing in a wide area use radio lines with poor transmission quality, it is possible to transmit data using random number digital codes with high transmission efficiency. In addition, in FIG. 3, mobile station Cl
, C2 have been synchronized with random numbers to the fixed station A1, but if these stations have not yet been tested, when transmitting and receiving with these stations, digital code transmission is performed without applying random numbers until the testing is completed.

In other words, the signal waveform shown in Figure 5, 3-T, is used to modulate the signal and transmit and receive it on the radio line.) In this case, the synchronization code N is sent in the same pattern for each frame, so all that is needed is to interrupt the synchronization code and receive N. For example, frame and bit synchronization can be obtained. In addition, if the mobile station, which has been set up for random number synchronization using the transmission wave from fixed station A1, wants to immediately transmit a digital code multiplied by a random number, it will be clear whether it is before or after the test by changing the radio frequency. Just do it. For example, Fl
, f2, or f3. When multiple mobile stations complete random number synchronization settings by transmission from fixed station A1 using either frequency f2 or f3, random number digital code transmission between the mobile stations is performed using F4 wave until the end of the test. After the inspection is completed, it will be carried out at 8. (F, ~F5 are all different frequencies) Then, the mobile station D1 receives on F5 and sets random number synchronization. As explained in detail above, using the method of the present invention, when performing mutual transmission and reception by multiplying complex random numbers over a line with generally poor transmission quality, such as a wireless line, random number synchronization settings can be easily obtained, and random number synchronization settings can be easily obtained. Even if synchronization deviates after a certain period of time, it can be corrected, making it easy to form a communication network.

Further, even when later interrupting this communication network and setting random number synchronization to perform mutual transmission/reception with a station for which random number synchronization has already been set, random number synchronization can be set without error, which is extremely effective in practice.

[Brief explanation of the drawing]

1 and 2 are circuit configuration examples of a transmitting device and a receiving device implementing the present invention, respectively, FIGS. 3 and 4 are configuration example diagrams of a communication network implementing the present invention, and FIG. 5 and FIG. Figure 6 shows the operation waveform diagrams of each part in Figures 1 and 2, respectively.
Figure 7 is a random number synchronization code diagram, Figure 8 is an outline diagram of the random number transmitting/receiving device (random number adding device and random number translation device), Figure 9 is a movement circulation diagram of random numbers, and Figure 10 is an example of random number synchronization test and correction. be. 1...Original information analog signal, 2...A
/D converter, 3... code processing circuit, 4...
... Synchronization signal addition device, 5+5a ... Random number addition device, 6 ... Modulator, 7 ... Transmission unit,
8... Receiving section, 9... Demodulator, 10+
10a...Random number translation device, 11...Random number synchronization check circuit, 12...Synchronization circuit, 13...
. . . code processing circuit, 14 . . . D/A converter, 15 . . . restored analog signal.

Claims (1)

[Claims] 1. When performing digital transmission over wireless lines between multiple mobile stations in a wide area by adding random numbers to the original digital signal for secrecy, a fixed station installed in the area is used to set up synchronization. , a random number synchronization code having a predetermined code combination and a transmission order that is initially transmitted for a certain period of time, and a random number digital signal containing an information signal multiplied by a random number by these random number synchronization codes, The reception data extracted at regular intervals is compared with the random number synchronization code and the order of arrival of the random number synchronization code set in the random number synchronization check circuit of the target station according to the random number setting rules agreed upon in advance between the mobile station and the fixed station. After performing random number synchronization setting by inspecting the code of a certain bit length in the code and finding the break point of the random number synchronization code in the received code, a communication network between mobile stations is formed,
Thereafter, each mobile station checks whether the random number synchronization is out of order using the random number digital signal transmitted from the fixed station for a certain period of time at a predetermined time, by performing the same random number synchronization settings as above. If there is an error, the mobile station corrects the bit before communicating, and if it interrupts the communication network and communicates with another mobile station, it must pass the above inspection. A mobile communication system characterized in that mutual communication is performed after random number synchronization is set using synchronization codes that arrive at regular intervals in received codes from mobile stations.