JP2001094536A - System and device for data transmission and reception - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep data completely secret by disabling physical reception from the outside by radio although the data were kept secret to some extent before through deciphering, etc. SOLUTION: A directional antenna 24a of a data transmission and reception device A receives even a disturbing wave sent from a nondirectional antenna 25a together with a digital modulated wave sent from a directional antenna 24b of a data transmission and reception device B. The digital modulated wave and disturbing wave received by the directional antenna 24a are supplied to an adder 11 through a switch 26a and added to a phase-inverted disturbing wave from an attenuator 13 to cancel the disturbing wave components and the wave is inputted to a demodulation part 14. When a reception device other than the data transmission and reception device A tries to receive a transmit digital modulated wave of the data transmission and reception device B, a disturbing wave sent by the data transmission and reception device A is also received together with a transmit digital modulated wave of the data transmission and reception device B, so normal demodulation can not be performed because of the disturbing wave to prevent wiretapping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data transmitting / receiving system and a data transmitting / receiving apparatus, and more particularly to a data transmitting / receiving system and a data transmitting / receiving apparatus for transmitting / receiving data by wireless communication.

[0002]

2. Description of the Related Art Conventionally, a low-power radio device is installed on a power pole on which an optical fiber is laid, and by accessing a general home near the power pole by radio, an optical fiber of a power company intended for use, such as the Internet, is used. Communication networks are known. In a data transmitting / receiving device used in such a communication network, it is important to secure the secrecy of communication.

[0003]

However, in the above-mentioned conventional data transmitting / receiving apparatus, although a certain degree of confidentiality is protected by data encryption or the like, it can be physically received from the outside because wireless is used. Its confidentiality has its limits.

[0004] The present invention has been made in view of the above points,
An object of the present invention is to provide a data transmission / reception system and a data transmission / reception device capable of wirelessly transmitting and receiving highly confidential data with a simple configuration.

[0005]

In order to achieve the above object, a data transmission / reception system according to the present invention is characterized in that a reception apparatus receives a digital modulation wave wirelessly transmitted from a transmission apparatus, and demodulates and decodes the digital modulation wave. In a data transmission / reception system that obtains transmission data by using an interfering wave transmitting means for transmitting an interfering wave, a receiving means for receiving a digital modulation wave together with the interfering wave, and a phase of the interfering wave transmitted from the interfering wave transmitting means, Adjusting means for adjusting the amplitude and amplitude, respectively, and removing means for canceling and removing the interfering wave component contained in the digital modulated wave received by the receiving means with the interfering wave whose phase and amplitude have been adjusted by the adjusting means. And a demodulating / decoding means for demodulating and decoding the received digital modulated wave output from the removing means.

According to another aspect of the present invention, there is provided a data transmission / reception apparatus for generating an interference wave, an interference wave transmission unit for transmitting an interference wave, and an externally transmitted digital modulation unit. Receiving means for receiving a wave together with an interfering wave transmitted by the interfering wave generating means, adjusting means for adjusting the phase and amplitude of the interfering wave generated by the interfering wave generating unit, and a digital modulated wave received by the receiving means Removing means for canceling out the interference wave component contained in the interference wave whose phase and amplitude have been adjusted by the adjusting means, and demodulation for demodulating and decoding the received digital modulated wave output from the removing means A configuration having decoding means;

The data transmission / reception system and the data transmission / reception apparatus of the present invention receive an interference wave transmitted by itself at the time of reception together with a digital modulation wave, and cancel and remove the interference wave whose phase and amplitude have been adjusted by the adjusting means. , Reception by a device having no adjusting means can be prevented.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a data transmitting / receiving system and a data transmitting / receiving apparatus according to the present invention. The data transmission / reception system of the present invention shown in FIG.
It comprises two data transmitting and receiving apparatuses A and B according to an embodiment of the present invention which are provided to face each other at a relatively short distance. For example, one is attached to a telephone pole and the other is installed in a house.

The data transmission / reception devices A and B have the same configuration, and each of the reception units 10a and 10b and the control unit 21a,
21b, the internal connection buses 22a and 22b, and the transmission unit 23
a, 23b, directional antennas 24a, 24b, non-directional antennas 25a, 25b, and switches 26a, 26b
, Connectors 27a, 27b, distributors 28a, 28b
And data transmission / reception units 29a and 29b.

The receiving unit 10a adjusts the power of the adder 11, a phase shifter 12 as interference wave removing means for inverting the phase of the interference wave generated inside the receiving unit 10a, and the output inverted interference wave of the phase shifter 12. An attenuator 13, a demodulator 14 for demodulating a digitally modulated radio wave which is an output signal of the adder 11, a decoder 15 for decoding an output demodulated signal of the demodulator 14, and an interfering wave generator 16 for generating an interfering wave. Consisting of Receiver 10
b has the same configuration. The interfering wave is a frequency within the transmission / reception frequency band of the digital modulation wave transmitted / received by the data transmission / reception devices A and B.
It is desirable that the frequency and pattern of the interfering waves respectively generated from each other are different from each other in order to improve confidentiality.

The control units 21a and 21b include a receiving unit 10a,
10b, transmitting units 23a and 23b, switching units 26a and 2b,
6b, connectors 27a and 27b, and a data transmitting / receiving unit 29
a, 29b. Internal connection buses 22a, 22b
Are transmitted to the control units 21a and 21b by the reception units 10a and 1b.
0b, transmission units 23a and 23b, and switches 26a and 26
b, connectors 27a and 27b, and a data transmitting / receiving unit 29
a and 29b. The transmission units 23a and 23b encode the transmission data and modulate the data into digital modulation waves. The directional antennas 24a and 24b radiate the above-mentioned digitally modulated waves as radio waves or receive digitally modulated waves. The omnidirectional antennas 25a and 25b
a, and wirelessly transmit signals from 28b.

The switches 26a and 26b switch the connection between the directional antennas 24a and 24b and the receiving units 10a and 10b or the transmitting units 23a and 23b. Connector 27
a and 27b are the receiving units 10a and 10b and the distributor 28
a, the connection with 28b is interrupted. Distributors 28a, 28b
Distributes the interference wave generated by the receiving units 10a and 10b to the non-directional antennas 25a and 25b and the receiving units 10a and 10b. The data transmitting / receiving units 29a and 29b
a, 10b and the transmission units 23a, 23b and exchange data with the outside.

Next, the operation of this embodiment will be described with reference to FIG. Here, interference waves are generated at the time of transmission and reception using modulated radio waves,
A case where a modulated radio wave is decoded while removing the influence of an interfering wave will be described. It is assumed that the radio wave transmitted from the data transmitting / receiving device B is received by the data transmitting / receiving device A through a known line connection procedure. At time t1 in this case, FIG.
As schematically shown in (C), in the data transmission / reception apparatus B, the switch 26b is connected to the transmission unit 23b, so that the input data is encoded and modulated, and transmitted as a digital modulation wave from the directional antenna 24b. I do. At this time, since the connector 27b is cut off as schematically shown in FIG. 2D, no interfering wave is transmitted from the omnidirectional antenna 25b.

On the other hand, in the data transmitting / receiving apparatus A that has received the incoming call notification by a known procedure, at the time t1, the data
As schematically shown in (A), since the switch 26a connects the directional antenna 24a to the receiving unit 10a, the digital modulation wave transmitted from the directional antenna 24b of the data transmitting / receiving apparatus B has a directivity. The signal is received by the antenna 24a.

In the data transmitting / receiving apparatus A, at the time t1, the connector 27a is in the connected state as schematically shown in FIG. The interference wave generated from the section 16 is
a to a splitter 28a, where the signal is split into two, one of which is input to the phase shifter 12 in the same receiving unit 10a and whose phase is inverted, and the other is input to the omnidirectional antenna 25a and transmitted therefrom. Is done.

Accordingly, at this time, the directional antenna 24a of the data transmitting / receiving apparatus A is provided with the omnidirectional antenna of the data transmitting / receiving apparatus A itself together with the digital modulated wave transmitted from the directional antenna 24b of the data transmitting / receiving apparatus B. The interference wave transmitted from 25a is also received. The digital modulation wave and the interfering wave received by the directional antenna 24a are supplied to the adder 11 in the receiving unit 10a through the switch 26a, and are added to the phase inversion interfering wave from the attenuator 13.

Here, the attenuator 1 input to the adder 11
3, the phase shift amount of the phase shifter 12 and the attenuator are set in advance so that the phase of the interference wave component in the received signal input to the adder 11 through the switch 26a is inverted and the amplitude becomes the same. Thirteen attenuations are adjusted. This allows
The interfering wave component in the received signal input to the adder 11 is canceled by the interfering wave input from the attenuator 13 to the adder 11 and input to the demodulation unit 14. The demodulation unit 14 demodulates the input received signal without the influence of an interference wave, and
, Where the error is corrected and decoded. Decoding unit 1
5 is supplied to the data transmitting / receiving unit 29a,
This will output to the outside.

Here, when an attempt is made to receive the transmission digital modulation wave of the data transmission / reception apparatus B by a reception apparatus other than the data transmission / reception apparatus A, not only the transmission digital modulation wave of the data transmission / reception apparatus B but also the data transmission / reception apparatus Will also receive the transmitted interfering wave, so that it cannot be demodulated normally due to the interfering wave and wiretapping can be prevented.

It is assumed that the radio wave transmitted from data transmitting / receiving apparatus A at time t2 is received by data transmitting / receiving apparatus B. At time t2 in this case, since the switch 26a is connected to the transmitting unit 23a in the data transmitting / receiving device A as schematically shown in FIG. 2A, the input data is encoded and modulated, and The modulated wave is transmitted from the directional antenna 24a. At this time, the connector 27a is
Since it is cut off as schematically shown in (B), no interfering wave is transmitted from the omnidirectional antenna 25a.

On the other hand, in the data transmission / reception apparatus B, at the time t2, as shown schematically in FIG. 2C, the switch 26b connects the directional antenna 24b to the reception unit 10b. Directional antenna 24 of transmitting / receiving apparatus A
The digitally modulated wave transmitted from a is received by the directional antenna 24b. Also, the connector 27b is shown in FIG.
As shown schematically in FIG. 2, the interfering wave generated from the interfering wave generator in the receiver 10b is supplied to the distributor 28b through the connector 27b.
One is input to the same receiving unit 10b, and the other is input to the omni-directional antenna 25b and transmitted therefrom.

Therefore, in this case, contrary to the above case, the digital modulation wave transmitted from the data transmission / reception device A by the data transmission / reception device B is demodulated and decoded, and data can be normally obtained without the influence of the interference wave.

The present invention is not limited to the above embodiment. For example, the present invention controls the interference wave generated by the interference wave generator 16 so that it can be generated in several types of patterns. Phase shifter 12 according to each pattern
By controlling the amount of phase transition and the amount of attenuation of the attenuator 13 by the control unit 21a, it is possible to transmit and receive more confidential data. Further, the connection order of the phase shifter 12 and the attenuator 13 may be reversed.

[0023]

As described above, according to the present invention,
During the reception, the self-transmitted interfering wave is received together with the digital modulation wave, and the interfering wave whose phase and amplitude have been adjusted by the adjusting means is canceled and removed, thereby preventing reception by a device having no adjusting means, so that external adjustment is performed. Even if an attempt is made to eavesdrop by another device having no means, demodulation can be disabled. Further, according to the present invention, a highly confidential communication can be realized with a simple configuration by reversing the idea of transmitting a disturbing wave on the receiving side.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of a data transmission / reception system and a data transmission / reception device of the present invention.

FIG. 2 is an explanatory diagram of a connection state of each unit for explaining the operation of FIG. 1;

[Explanation of symbols]

 A, B Data transmitting / receiving device 10a, 10b Receiving unit 11 Adder 12 Phaser 13 Attenuator 14 Demodulating unit 15 Decoding unit 16 Interference wave generating unit 21a, 21b Control unit 22a, 22b Internal connection bus 23a, 23b Transmitting unit 24a, 24b Directional antennas 25a, 25b Non-directional antennas 26a, 26b Switches 27a, 27b Connectors 28a, 28b Dividers 29a, 29b Data transceiver

Claims (6)

[Claims] 1. A data transmitting / receiving system in which a receiving device receives a digitally modulated wave wirelessly transmitted from a transmitting device and demodulates and decodes the digitally modulated wave to obtain transmission data, wherein the receiving device transmits an interference wave. Interfering wave transmitting means, receiving means for receiving the digital modulated wave together with the interfering wave, adjusting means for adjusting the phase and amplitude of the interfering wave transmitted from the interfering wave transmitting means, and the receiving means Removing means for canceling and removing the interfering wave component included in the received digital modulation wave from the interfering wave whose phase and amplitude have been adjusted by the adjusting means, and the reception output from the removing means And a demodulation / decoding means for demodulating and decoding the digitally modulated wave. 2. The interfering wave transmitting means generates and outputs an interfering wave of one type selected from a plurality of types of pattern interfering waves, and the adjusting means selects one of the pattern interfering waves selected by the interfering wave transmitting means. 2. The data transmission / reception system according to claim 1, wherein the amount of adjustment of the phase and the amplitude is variably controlled in accordance with the interference wave of the type of pattern. 3. An interfering wave generator for generating an interfering wave, an interfering wave transmitter for transmitting the interfering wave, and a digitally modulated wave transmitted from outside together with the interfering wave transmitted by the interfering wave generator. Receiving means for receiving; adjusting means for respectively adjusting the phase and amplitude of the interference wave generated by the interference wave generation unit; and the interference wave component contained in the digital modulated wave received by the reception means Removing means for canceling and removing the interference wave whose phase and amplitude have been adjusted by the adjusting means, and demodulating and decoding means for demodulating and decoding the received digital modulated wave output from the removing means. A data transmitting / receiving device, comprising: 4. The data transmission / reception apparatus according to claim 3, wherein said interference wave transmitting means has an omni-directional antenna, and said receiving means has a directional antenna. 5. An interfering wave generator for generating an interfering wave, an omnidirectional antenna for transmitting the interfering wave, and a connection for intercepting the interfering wave from the interfering wave generator during transmission and transmitting the interfering wave during reception. An adjusting unit for adjusting the phase and amplitude of the interfering wave, a distributor for dividing the interfering wave input through the connector into the omnidirectional antenna and the adjusting unit, and transmitting from the outside. A directional antenna that receives the digitally modulated wave thus transmitted together with the interfering wave transmitted from the omnidirectional antenna, a transmitting unit that modulates data to be transmitted into a digitally modulated wave, Adding the digitally modulated wave and the interfering wave to the interfering wave whose phase and amplitude have been respectively adjusted by the adjusting means, and adding the interfering wave component contained in the received digitally modulated wave An adder for canceling out, and transmitting the digital modulated wave from the transmitting unit to the directional antenna for transmission and transmitting the digital modulated wave and the interfering wave received by the directional antenna during reception. A switch that supplies the adder, a demodulator / decoder that demodulates and decodes the received digital modulated wave output from the adder, and transmits the operations of the connector, the distributor, and the transmitter when transmitting. 4. The data transmitting / receiving apparatus according to claim 3, further comprising a control unit configured to perform control according to reception. 6. The interfering wave generating unit generates and outputs an interfering wave of one type selected from a plurality of types of interfering waves, and the adjusting unit selects one of the interfering waves selected by the interfering wave transmitting unit. The data transmission / reception device according to any one of claims 3 to 5, wherein the amount of adjustment of the phase and the amplitude is variably controlled in accordance with the interference wave of the type of pattern.