JP2002027000A - Communication equipment using carrier modulated by random number code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication equipment with excellent confidentiality. SOLUTION: The communication equipment is provided with a random number code generator employing a noise, or a radiant ray, or a numeric expression at its receiver side. The receiver side transmits a carrier modulated by the random number code, a transmitter side uses a modulation code receiver 8 to receive the carrier sent from the receiver side, uses data to modulate this carrier and transmits the modulated data, and the receiver side applies addition/ subtraction or multiplication/division of the carrier sent to the transmitter side from the received modulation wave to demodulate the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting device and a receiving device applied to data communication and two-way communication, and to a communication device applicable to all communication fields such as telephones and portable terminals. is there.

[0002]

2. Description of the Related Art In conventional communication, a carrier generated on a transmitting side is modulated with a signal or data and transmitted to a receiving side, and the receiving side demodulates the received modulated wave as it is, or uses the same carrier as the transmitting side. Generally, a method of demodulating a modulation wave received by itself and extracting a valid signal or data has been used. Modulation methods include AM, FM, ASK, FSK, PS
Analog systems such as K, APK, QMA, and FDM
Digital systems such as A, TDMA, and CDMA are widely known.

[0003] In these communication systems, in order to ensure the security of communication data, the data itself is encrypted on the transmission side, a carrier wave is modulated with the encrypted data and transmitted to the transmission side, and the reception side transmits data. There is also a communication system that demodulates the carrier wave modulated by the method described above, decodes the carrier wave by using an encryption secretly determined in advance with the transmitting side, and obtains effective data.

As an example of such a communication system, the CDMA (Code Division) using a spread spectrum technique is used.
A Mnltipie Access (Code Division Multiple Access) system is known, and the CDMA communication system can be further divided into a direct spread system (DS system) and a frequency hopping system (FH system) depending on the spread spectrum technique used.

FIG. 11 shows a block diagram of a transmitter using the direct spreading method, and FIG. 12 shows a block diagram of a receiving device.

In the case of the direct spreading system, on the transmitter 50S side, data is modulated by the data modulator 1 with the basic carrier from the carrier generator 2, and the data is further passed through the next-stage wideband code modulator 3 to the PN code. PN from generator 11
(Pseudorandom Noise: Pseudorandom Noise) code, and transmitted to the receiver 50R side.

FIG. 13 shows the relationship between data, a PN code, and a spread signal modulated by the wideband code modulator 3. PN
The codes are +1,-as well as digital data after data modulation.
Taking two values of 1, the period of the change (spreading factor) is
For example, in the case of CDMA1, it is 128 times. In this spreading method, the frequency band after spreading has a larger power density distribution (equal to the spreading factor) than that before spreading, as shown in FIG. In addition, unnecessary signals can be eliminated.
On the other hand, on the receiver 50R side, signal operation completely opposite to that on the transmission side is performed. That is, in the block diagram of FIG. 12, the receiver 50R has the same PN code generator 1 as the transmitting side.
1 to generate a PN code, and perform code synchronization tracking 7
The PN code is subtracted from the spread signal received by the code demodulator 6 while taking the timing described above, and the data is further demodulated based on the carrier from the carrier generator 2 to obtain valid signals and data.

CDMA by Frequency Hopping Method
Communication FIG. 15 is a block diagram of a transmitter using the frequency hopping method, and FIG. 16 is a block diagram of a receiver.

In the spread spectrum of the frequency hopping method, the transmitter 50S converts the frequency of the modulated data from the baseband modulator 16 via the frequency synthesizer 14 and the up-converter 15 based on the code timing of the PN code generator 11. With this method, the carrier frequency flies randomly and widely. FIG. 17 shows an example of the frequency hopping pattern at this time, and FIG. 18 shows the relationship between the frequency distribution before and after spreading and the power density. In the receiver 50R, the operation just opposite to that of the transmitting side may be performed, and the same hopping pattern as the PN code on the transmitting side is created via the carrier generator 17, the PN code generator 11, and the frequency synthesizer 14, and the down converter At 20, the original data signal can be extracted.

Further, in this frequency hopping method, SFH (Slow FH) and FFH (Fast FH) are determined by the ratio between the signal rate (bit rate) of the primary modulation and the hopping rate.
H). FFH is difficult to operate at high speed,
On the other hand, SFH is mainly used for military applications because it can be spread over a wide band, and SFH is mainly used for mobile phones and the like because it can be manufactured at low cost. In any case, in order to extract the transmitted signal (despreading), it is necessary to multiply the same PN code used for the spreading at the same timing as when the spread is performed. It is restricted and usually has a control channel. For timing adjustment, synchronization acquisition and synchronization tracking after acquisition are performed by separate circuits. Representative examples are a serial search method and a matched filtering method.

FIG. 19 is a block diagram of a typical synchronization acquisition circuit 70 using the serial search method. In the serial search method, a received spread signal is demodulated with a PN code generated at an appropriate timing, and it is checked whether a signal of a certain level can be obtained through a low-pass filter. This operation is repeated while changing the timing of the PN code, and synchronous tracking is started when a signal of a certain level is detected. However, there are the following problems (1) to (4). (1) The generation timing of the PN code should be adjusted for each chip. However, in practice, it is not necessarily synchronized for each chip, so the adjustment must be performed at intervals shorter than one chip. (2) To check if the timing is correct,
It takes one cycle of the PN code for each timing. In the worst case, it takes 2 ^K -1 times (k: the bit length of the PN code) the time for one period of the PN code. (3) Depending on the influence of noise, it is not possible to confirm whether synchronization has been achieved only by examining one cycle. Therefore, it is necessary to confirm whether the found timing is correct. (4) If a different signal interferes during one period of the PN code during data communication, there is a possibility that the synchronization acquisition timing to be detected may be erroneous, so that data cannot be transmitted until synchronization acquisition is confirmed.

The matched filtering method is a method that uses a SAW element (surface acoustic wave element) that operates similarly to a shift register that handles an analog waveform. This is W
It is used in the CDMA system, and is characterized in that synchronous acquisition can be performed in one period of the PN code, but has a disadvantage that the bit length of the PN code is limited by the number of taps.

[0013] In the CMDA, in order to avoid the above-mentioned problem, a method of establishing inter-bit synchronization as shown in FIG. 20 is determined in advance. Even in the synchronous type CMDA (FIG. 20-a), since perfect synchronization is difficult depending on the used parts, the quasi-synchronous type CMDA (FIG. 20-b) is provided with an allowable range for phase deviation. CDMA1 uses G to avoid these problems.
Synchronized using PS.

The asynchronous type CMDA (FIG. 20-c) has the advantage that there is no need to synchronize at all, but since transmission is performed at random, the phase shift of the spreading code must be considered, and the PN code used Correlation value is 0 depending on the sequence
There are drawbacks such as not becoming a problem.

In the CDMA system, the only thing that separates users is the PN code used for spreading. If the cross-correlation between different spreading code systems becomes high, signals of other users are erroneously demodulated at the same time. For the PN code system used for spreading, Walsh code system is used for synchronous CMDA, and M is used for asynchronous CMDA.
Sequence or Gold sequence is used.

As a feature of the M-sequence, the probability that 0s or 1s appear continuously is close to a random number, and the power spectrum distribution is the same as that of thermal noise. Is small). If used carelessly, the cycle of the generated code is shortened. To avoid this, a Gold sequence obtained by simply adding two M sequences is used. According to this method, if the code length is k bits, 2 ^K +1 kinds of code sequences can be obtained from one circuit, and the absolute value of the cross-correlation value can be suppressed to about ^21/2 times of the M sequence at maximum. Although it is used for asynchronous CMDA, the cross-correlation cannot be set to 0 because it is created based on the M sequence. Also, this method has an inferior autocorrelation than the M sequence.

[0017]

As described above, the conventional communication system has a configuration in which the same carrier wave as that of the transmitting side is created and demodulated using the same, so that the receiving side generates carrier waves necessary for demodulation. It is necessary to incorporate a circuit and an oscillation circuit, and the circuit configuration has become complicated.

In the above-mentioned communication system, a carrier wave is open to the public, and since it is uniquely determined, it is a possible system. Therefore, there is a problem in securing the security of communication data (security). I was For example, in e-commerce and data communication using a mobile terminal, damages such as exploitation of the communication data or unauthorized processing of the communication data in the middle of the communication path due to external acts have been occurring frequently. Separately, communication means for encrypting data had to be used, and complicated circuits and software for encryption and decryption were required.

The present invention has been made in view of the above-mentioned conventional problems. A receiving side modulates a carrier with a random number code and transmits the modulated signal to a transmitting side, and the transmitting side uses the received carrier to transmit data and the like. It is an object of the present invention to provide a highly reliable communication device that secures excellent confidentiality by performing continuous encryption and decryption by a communication method different from the conventional one, that modulates a signal.

[0020]

In order to achieve the above object, a communication apparatus according to claim 1 transmits a carrier modulated with a random number code from a receiving side, and the transmitting side transmits the carrier wave transmitted from the receiving side. Modulation is performed using a carrier wave, and transmission is performed. On the receiving side, demodulation is performed by performing addition / subtraction or multiplication / division of the carrier wave transmitted to the transmission side from the received modulated wave.

The communication device according to the second aspect is characterized in that:
Communication of M, FM, ASK, FSK, PSK, APK, QMA, etc., or FDMA, TDMA, CDMA
A carrier generation device incorporating a random number code modulation circuit capable of communication of a system or the like is provided.

The communication device according to claim 3 is characterized in that:
M, FM, ASK, FSK, PSK, APK, and Q
Carrier generation circuit such as MA system, or FDMA, T
A carrier having a carrier generation circuit such as a DMA or CDMA system, and modulating a carrier from the carrier generation circuit required for transmission using a random pulse and a random number generated by a random number code generator when confidential communication is required It has a generator.

The communication device according to a fourth aspect of the present invention includes a receiving device capable of transmitting a carrier modulated with a random number code and receiving the carrier modulated on a data transmitting side.

A communication device according to a fifth aspect of the present invention includes a transmitting device that receives a carrier wave modulated with a random number code transmitted from a receiving device, modulates the carrier wave with data, and transmits the data to a receiving side. .

Further, the communication device according to the present invention includes a carrier generation device that uses a random pulse generated from a random number code generator as a direct carrier.

Further, the communication device according to the present invention includes a carrier generation device that uses a random number value generated by the random number code generator as a carrier random number value.

In the communication device according to the present invention, the random number code generator may include electric noise (thermal noise, white noise) or optical noise, radiation, or a mathematical expression (including a pseudo random number generator using software). The random number generator used was used.

The communication device according to the ninth aspect is configured to continuously perform modulation of transmission data including encryption and demodulation of reception data including decryption.

Further, the communication device according to the tenth aspect uses a carrier to be transmitted as an ID and an encryption key on the receiving side.

The communication device according to the eleventh aspect is used for a portable telephone or a portable terminal.

In the above configuration, since the data is encrypted by the carrier wave, sufficient confidentiality can be relatively easily secured without requiring a public key or a secret key as in the related art.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a communication device according to the present invention will be described below with reference to the drawings. To simplify the description, the same reference numerals are used in the following description for portions common to the related art.

FIG. 1 is a block diagram on the transmitter side in which the present invention is applied to the direct spreading system of CDMA communication.
Shows the block diagram of the receiver side,
FIG. 3 is a block diagram on the transmitter side when the present invention is applied to a frequency hopping scheme, and FIG.
3 shows a block diagram of a receiver.

According to the present invention, a carrier modulated by a natural random number code is transmitted from a receiving side, and a transmitting side modulates a carrier transmitted from a receiving side with data or the like without providing a carrier generating circuit required for transmission. In addition, the receiving side performs demodulation by removing the carrier wave by performing addition / subtraction or multiplication / division reverse to the modulation performed on the transmission side based on the received modulated wave, thereby extracting a valid signal.

Therefore, in the communication apparatus of the present embodiment shown in FIGS. 1 to 4, the receiver 50R transmits the carrier modulated by the random number code in any of the direct spreading system and the frequency hopping system. The transmitter 50S includes a modulation code receiver 8 (or a natural random number code receiver 21) for receiving a carrier modulated with a random number code transmitted from the receiver 50R. This point is fundamentally different from the conventional communication apparatus shown in FIGS. 11 and 12, and FIGS. Further, while the conventional device uses the PN code from the PN code generator 11 as the modulation code, the present embodiment uses the random pulse signal from the natural random number code generator 9 as the natural random number code. The points are also different.
The other configuration is the same as that of the conventional device, and the description is omitted.

In a satellite communication or the like, if a time difference that cannot be ignored from transmission to reception occurs, it is necessary to correct the time difference and synchronize it. In the case of the present invention, a common modulation is used on the transmission side and the reception side. Since a wave is used, the generated time difference is only a simple phase delay, so that a complicated circuit configuration such as the conventional CDMA system shown in FIG. 19 is not required for synchronization acquisition. However, a simple circuit such as a shift register can be used.

Here, the natural random number code generator 9 for generating a random number pulse for modulating the carrier described above will be described with reference to FIG.

As shown in FIG. 5, the natural random number code generator 9
Is a radiation source that emits radiation (α rays), a natural random number code generating element 24 having a semiconductor detector (for example, a PIN diode) for detecting the radiation source, a preamplifier 25 and a main amplifier 26, and a wave height discrimination circuit 27. And a waveform shaping unit 28 for generating a random pulse signal and a random analog waveform signal based on radiation energy from the α-ray source.

As shown in FIG. 6, from the natural random number generating element 24, a pulse (the waveform on the right side in FIG. 6) due to the energy of the α-ray (the waveform on the right side in FIG. 6) and the noise generated by the semiconductor detector itself (the waveform on the left side in FIG. 6). Is output, so that a method (signal range A in FIG. 6) in which both noise and a radiation signal are used depending on the speed required for modulation, the depth of the modulation level, and the like,
Any of the methods using only radiation (signal range B in FIG. 6) can be selected and used. In addition,
Of course, it is also possible to use the random number generation element 24 utilizing white noise such as resistance noise, thermal noise, and optical noise.
When using white noise, a pulse signal generated with energy up to about 0.3 keV is used as shown in FIG.

In the communication apparatus of the present invention, the natural random number code generator 9 is mounted on the receiver side, and in a digital system such as the above-mentioned CMDA, the natural random number code is used instead of the conventional PN code or hopping pattern. Code modulation is performed using a random pulse signal generated by the code generator 9, and in an analog system such as AM or FM, analog modulation is performed using a random analog signal. Therefore, the correlation value can be set to 0 in any case. In addition, the number of users that can be used in the same frequency also depends on the length of the random number code used for spreading. In contrast to the conventional CMDA system in which the number of users is 20 to 30, the present invention significantly increases the number. It is possible.

In the above-mentioned analog modulation such as AM and FM, a carrier generation circuit 30 for data modulation shown in FIG. 8 and a data demodulation circuit 40 shown in FIG. 9 are mounted on the receiver side.

The carrier generation circuit 30 converts the carrier basic signal (FIG. 10-b) from the basic carrier generation circuit 31 through the random number modulation circuit 32 into a random analog signal (FIG. 10-a) from the natural random number code generator 9. And the combined waveform (FIG. 10-c) is used as a carrier. The modulated carrier is transmitted from the receiving side to the data transmitting side, and the data transmitting side further modulates the received carrier with transmission data and transmits the modulated carrier to the receiving side. The receiving side receives this in the data demodulation circuit 40,
Inverse conversion is performed using the carrier wave of the carrier wave generation circuit 30 sent to the transmission side via the carrier wave separation circuit 41 in the same manner as in the above-mentioned CMDA method, and valid data and signals are extracted.

Here, the carrier wave delay circuit 42 is a circuit for adjusting the timing so that the carrier wave arrives at the transmitting side, and is the same as the time difference from when the carrier wave is modulated by the data and back.

In the above embodiment, the CDMA system has been described. However, the communication system is not limited to this, and AM, FM, ASK, FSK, PSK, A
Analog communication such as PK and QMA, or FDM
By incorporating a data modulation circuit using the above-mentioned random number code in digital communication such as A, TDMA, etc., these communication systems can be widely supported.

As described above, the communication apparatus of the present invention modulates a carrier with a random pulse or a random code generated from a natural random number code generator without using a public key or a secret key as in the related art. Communication confidentiality can be reliably ensured. Further, in the present invention, since the carrier to be transmitted itself is encrypted, it is possible to use this carrier as the ID of the receiving side, and further, it is also possible to use this random pulse directly as the carrier. is there.

[0046]

As described above, the communication apparatus of the present invention is provided with a random number code generator for each receiver, and modulates a carrier with a random number code and a random number pulse of the random number code generator to transmit the signal to the signal transmitting side. , And receives the signal and carrier transmitted from the transmitting side, and removes (demodulates) the carrier using the random number code generated by itself, thereby extracting the target signal. Even if the transmission signal is received, the signal cannot be demodulated unless the random number code or the random number pulse itself modulating the carrier wave is simulated, so that the confidentiality of the communication is ensured. When a random number code is created using perfect natural random numbers created with α rays or the like and applied to CDMA or the like, since the signal is almost equal to the noise level due to spectrum spreading, the random number is calculated from the noise level. Is almost impossible to retrieve, and thus the security is significantly improved compared to the conventional method.

Also, by selecting random numbers based on white noise or natural random numbers of perfect random numbers in accordance with the level of security, the confidentiality of communication can be relatively easily secured by a method completely different from conventional communication methods. It is most suitable for mobile phones and mobile terminals that require confidentiality.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmitter when the present invention is applied to a direct spreading system of CDMA communication.

FIG. 2 is a block diagram of a receiver when the present invention is applied to a direct spreading system of CDMA communication.

FIG. 3 is a block diagram of a transmitter when the present invention is applied to a frequency hopping scheme of CDMA communication.

FIG. 4 is a block diagram on the receiver side when the present invention is applied to a frequency hopping scheme of CDMA communication.

FIG. 5 is a diagram showing a circuit configuration of a natural random number generator according to the present invention.

6 is a diagram showing a use range of a signal generated from the natural random number code generation element of FIG.

FIG. 7 is a diagram illustrating a use range of a signal due to white noise.

FIG. 8 is a block diagram of a carrier generation circuit.

FIG. 9 is a block diagram of a data demodulation circuit.

FIG. 10 is a diagram showing waveforms at various parts in FIG. 8;

FIG. 11 is a block diagram on the transmitter side in a conventional direct spreading method of CMDA communication.

FIG. 12 is a block diagram on the receiver side in a conventional direct spreading method of CMDA communication.

FIG. 13 is a diagram showing waveforms at various parts in FIG. 11;

FIG. 14 is a diagram showing a frequency distribution in the direct spreading method.

FIG. 15 is a block diagram on the transmitter side in the frequency hopping method of the conventional CMDA communication.

FIG. 16 is a block diagram on the receiver side in the frequency hopping system of the conventional CMDA communication.

FIG. 17 is a diagram illustrating a frequency hopping pattern.

FIG. 18 is a diagram showing a frequency distribution in a frequency spreading method.

FIG. 19 is a block diagram of a synchronization acquisition circuit.

20A and 20B are diagrams showing a method of synchronous acquisition, wherein FIG. 20A shows a case of synchronization, FIG. 20B shows a case of quasi-synchronization, and FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 data modulator 2 carrier generator 3 wideband code modulator 4 data demodulator 6 code demodulator 7 code synchronization tracking 8 modulation code receiver 9 random code generator (natural random code generator) 10 natural random code transmitter 14 frequency Synthesizer 15 Upconverter 16 Baseband modulator 21 Natural random number code receiver 30 Carrier generator (carrier generator) 31 Basic carrier generator 32 Random modulator 40 Data demodulator 50S receiver (receiver) 50R transmitter (transmitter) )

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J104 FA10 HA04 NA02 NA05 PA02 5K004 AA01 AA03 AA04 AA05 AA08 BA02 DA01 DD00 DF00 DG04 EA01 EE00 EG00 FA01 FE00 FG00 JA01 JE00 JG00 5K022 EE02 EE23 EE31

Claims (11)

[Claims] 1. A receiving side transmits a carrier modulated with a random number code, a transmitting side modulates and uses the carrier transmitted from the receiving side, and a receiving side transmits from the modulated wave received. A communication device for performing demodulation by performing addition / subtraction or multiplication / division of the carrier transmitted to the side. 2. AM, FM, ASK, FSK, PSK,
Communication such as APK, QMA, or FDMA, T
The communication device according to claim 1, further comprising a carrier generation device incorporating a random number code modulation circuit capable of performing communication such as DMA or CDMA. 3. AM, FM, ASK, FSK, PSK,
It has a carrier generation circuit such as an APK and QMA system or a carrier generation circuit such as an FDMA, TDMA, or CDMA system, and uses a random pulse and a random number generated by a random number code generator when confidential communication is required. The communication device according to claim 1, further comprising a carrier generator that modulates a carrier from the carrier generator required for transmission. 4. The apparatus according to claim 1, further comprising a receiving device capable of transmitting a carrier wave modulated with a random number code and receiving the carrier wave modulated on a data transmitting side. The communication device according to any one of the above. 5. A transmitting apparatus for receiving a carrier modulated by a random number code transmitted from a receiving apparatus, modulating the carrier with data, and transmitting the modulated data to a receiving side. 3. The communication device according to any one of 3). 6. The communication device according to claim 1, further comprising a carrier generator that uses a random pulse generated from a random number code generator as a direct carrier. 7. The communication device according to claim 1, further comprising a carrier generator that uses a random number value generated from the random number code generator as a carrier random number value. 8. The random number code generator according to claim 6, wherein the random number code generator is an electric noise, optical noise, radiation, or a random number code generator using a mathematical expression. Communication device. 9. The communication apparatus according to claim 1, wherein modulation of transmission data including encryption and demodulation of reception data including decryption are continuously performed. 10. The communication device according to claim 3, wherein a carrier to be transmitted is used as an ID and an encryption key on the receiving side. 11. The communication device according to claim 1, wherein the communication device is used for a mobile phone or a mobile terminal.