JPH04274629A - Spread spectrum communication equipment for frequency hopping system - Google Patents

Abstract

PURPOSE:To avoid mistake in re-setting of a frequency hopping pattern and to keep ciphering by activating a spread spectrum modulation section selected by plural spread spectrum modulation sections as an information use, using other for a trickery modulation section, activating them in time division, synthesizing and outputting the synthesized output information. CONSTITUTION:A changeover section 16 supplies information of a modulated wave obtained by an information modulation section 6 to either of spread spectrum modulation sections 71, 72 selectively in time division, the one is used for information and the other is activated for trickery. Then output information sets of the modulation sections 71, 72 are synthesized and the result is sent to a reception system 2. Thus, trouble of resetting of a hopping pattern and its resetting mistake are avoided and leakage of the hopping pattern to the outside is prevented.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a frequency hopping (FH) type spread spectrum communication device in which one of a plurality of spread spectrum modulation units in a transmission system operates for information and the other for deception. .

0002

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional frequency hopping type spread spectrum communication device disclosed in, for example, Japanese Unexamined Patent Publication No. 1-132212.
1 is an information transmission system, 2 is an information reception system, 3 is an information transmission system which constitutes the transmission system 1, 4 is a deception transmission system which constitutes the transmission system 1, 5 is information, 5A is deception information, 6 6A is an information modulation unit that modulates a carrier wave with an information signal; 6A is a deception information modulation unit that modulates a carrier wave with a deception signal; 7 is a spread spectrum modulation unit that discretely sweeps the frequency of the modulated wave in a fixed pattern;
7A is a deceptive spread spectrum modulation unit that similarly sweeps the modulated frequency for deception, 8 and 8A are a code unit that creates a frequency hopping pattern and a deceptive code unit, 9 is an output information synthesis unit, 10 is an antenna, and 11 is a spreading unit. This is an information demodulation section that demodulates a narrowband modulated wave from a converted modulated wave.

Next, the operation will be explained. First, in the information transmission system 3, the information 5 is an analog audio signal, a digital signal obtained by analog/digital conversion of an analog signal,
Or it is a data signal. In wireless communication, the information 5 is a low frequency signal (generally called a signal wave) and cannot be transmitted as is, so the information 5 is added to a high frequency signal (generally called a carrier wave) created in advance by the information modulation section 6.
Give changes according to. Changing a carrier wave by a signal wave is called modulation, and the modulated carrier wave is called a modulated wave. There are several modulation methods depending on the content of the information 5. Generally, when the information 5 is an analog signal, amplitude modulation, frequency modulation, phase modulation, etc. are used, and when the information 5 is a digital signal or data signal. In this case, phase shift keying, frequency shift keying, etc. are used.

The carrier wave (modulated wave) modulated according to the information 5 by the information modulator 6 has its spectrum spread by the spread spectrum modulator 7 . Spread spectrum modulation can be divided into direct sequence modulation, frequency hopping, and other methods, but the frequency hopping method is used here. In frequency hopping type spread spectrum modulation, the frequency of a carrier wave modulated according to information 5 by the information modulation section 6 is
This is achieved by discretely switching and sweeping within a given band in a certain pattern (the content of the pattern is determined by the user before starting communication). The encoder 8 generates a frequency hopping pattern for discretely switching the frequency of the carrier wave (modulated wave) modulated according to the information 5 by the information modulator 6 in a certain pattern by the spread spectrum modulator 7. It has the function of creating.

Next, the deception transmission system 4 will be explained. The basic operation of this deception transmission system 4 is almost the same as that of the information transmission system 3, but the frequency hopping pattern created by the deception code section 8A is
The frequency hopping pattern produced by

That is, the deceptive information 5A is an analog signal, a digital signal obtained by analog/digital conversion of an analog signal, or a data signal. Similar to the information transmission system 3, in wireless communication, the deceptive information 5A is a low frequency signal and cannot be transmitted as it is, so the deceptive information 5A is combined with a high frequency signal generated in advance by the deceptive information modulator 6A. Give appropriate changes. The spectrum of the deceptive information 5A modulated by the deceptive information modulator 6A is spread by the deceptive spread spectrum modulator 7A. Also in this case, like the information transmission system 3, the frequency hopping method is used. The deception code section 8A converts the frequency of the carrier wave modulated according to the deception information modulation section 5A into a deception spread spectrum modulation section 7A.
It has a function to create a frequency hopping pattern for discrete switching in a certain pattern. Note that the frequency hopping pattern created by the deceptive code unit 8A is temporally the same as the frequency hopping pattern created by the code unit 8 in the information transmission system 3,
Alternatively, in the case of a multiplication relationship, the information transmission wave may be obstructed by the deception transmission wave. Therefore, the deceptive code part 8A must be synchronized with the code part 8, and the frequency hopping pattern for deception created by the deceptive code part 8A and the frequency hopping pattern for information created by the code part 8 must always be different patterns. Must be. Therefore, in order to synchronize the code section 8 and the deceptive code section 8A, for example, an accurate and reliable universal time, that is, an accurate clock common to the code section 8 and the deceptive code section 8A, is prepared, and synchronization is thereby performed. universal timing (absolute synchronization)
There are several possible methods.

Next, as shown in FIG.
The information spread spectrum modulated wave 15 created by the deception transmission system 4 and the deception spread spectrum modulated wave 14 created by the deception transmission system 4 are sent to the output information synthesis section 9.
The signals are combined into one spread-spectrum modulated wave and transmitted from the antenna 10. The spread spectrum modulated wave 15 for information is transmitted to the information transmission system 3.
The frequency hopping pattern frequency created in the code section 8 in the deception code section 8A is switched discretely, and the deceptive spread spectrum modulated wave 14 is created in the deception code section 8A in the deception transmission system 4. The frequency is switched discretely in a frequency hopping pattern, and synchronized with the spread spectrum modulated wave 15 for information.

Next, the receiving system 2 will be explained. Transmission system 1
The spread spectrum modulated wave transmitted from the transmitter is received by the receiving system 2, and by the reverse operation of the spread spectrum modulation performed on the transmitting system 1 side, the spectrum spread over a wide band is converted into a narrow band modulated wave. Convert. Generally, a received modulated wave is converted from a high frequency to an intermediate frequency by a frequency converter in a demodulation section, and then a signal wave is extracted to obtain information (this is called demodulation). Converting a modulated wave from a high frequency to an intermediate frequency using a frequency converter is achieved by supplying a local oscillation (local) signal to the frequency converter. In the case of frequency hopping type spread spectrum communication, the frequency is By switching the frequency of the local oscillation signal supplied to the converter in the same pattern and in synchronization with the frequency hopping pattern created by the code section 8 in the information transmission system 3,
A modulated wave can be obtained.

Next, the synchronization section 12 synchronizes with the code section 8 in the information transmission system 3, creates a frequency hopping pattern identical to the frequency hopping pattern created there, and controls the local oscillation signal. Furthermore, the received signal demodulated from the wideband spread spectrum modulated wave to the narrowband modulated wave by the spread spectrum demodulation section 11 is
The information demodulator 13 demodulates the signal into a signal wave. This signal wave becomes the same as the information 5 in the information transmission system 3. Note that the demodulation method is the same as that of the information modulation section 6 in the information transmission system 3. As described above, frequency hopping type spread spectrum communication is performed.

0010

[Problem to be Solved by the Invention] Since the conventional frequency hopping type spread spectrum communication device is configured as described above, the spread spectrum modulated wave transmitted from the transmission system 1 via the antenna 10 is As shown in FIG. 5, the spread spectrum modulated wave 15 for information and the spread spectrum modulated wave 14 for deception exist synchronously within a limited band. Spread spectrum modulated waves for information from receiving (intercepting) equipment that has a tuning speed faster than the switching speed of the modulated waves and has wideband performance, such as electronic support measures (ESM) equipment. Although it is possible to prevent decoding of frequency hopping patterns and interception of communication contents, information frequency hopping patterns and deception frequency hopping patterns, including synchronization timing, must be set by the user in advance for all communication devices. However, there were problems such as the possibility of human-induced setting errors and the risk of hopping patterns being leaked to the outside.

[0011] In addition, although the confidentiality of communication can be ensured by periodically changing the hopping pattern against leakage of the hopping pattern, it is also possible to ensure the confidentiality of communication by periodically changing the hopping pattern. Selecting a different pattern requires time for calculations, simulations, etc., requires a large amount of work including setting up all communication equipment, and has the problems of operational constraints.

[0012] Related prior art includes, for example, Japanese Patent Laid-Open No. 174842/1983.

The present invention was made to solve the above-mentioned problems, and provides a frequency hopping type spread spectrum communication device that maintains the confidentiality characteristic of spread spectrum communication and has operational flexibility. The purpose is to obtain.

[0014]

[Means for Solving the Problems] A frequency hopping type spread spectrum communication device according to the present invention provides a plurality of spread spectrum communication devices that discretely switch and sweep the frequency of a modulated wave obtained by an information modulating section in a fixed pattern. a modulation section; a code section connected to each of the spread spectrum modulation sections to create a frequency hopping pattern for the switching; and a code section that is connected to each of the spread spectrum modulation sections and transmits the information of the modulated wave obtained by the information modulation section to the plurality of spread spectrum modulation sections. and a switching unit that selectively supplies the signal to any of the above in a time-division manner, enables the selected spread spectrum modulation unit to operate as information use, and enables the other spread spectrum modulation units to operate as deception use; The output information of the spread spectrum modulator can be combined and transmitted to the receiving system.

[0015]

[Operation] In the present invention, two or more sets of spread spectrum modulation units 7 and code units 8 are not used separately for information/deception purposes, but any spread spectrum modulation unit 7 is selected for information use, and the remaining spread spectrum modulation By operating the unit 7 for deception and performing the switching between information and deception in a time-sharing manner, the conventional work in which the user had to reset the hopping pattern each time the hopping pattern was changed can be improved to just a switching operation. This makes it possible to maintain confidentiality, which is a feature of spread spectrum communication.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 16 denotes a switching unit that distributes the information of the modulated wave from the information modulation unit in a time division manner, and 71 and 72 receive the information of the modulated wave distributed and outputted by the switching unit, and the modulated wave 81 and 82 are connected to each of the spread spectrum modulation sections to create a frequency hopping pattern for the switching, and 9 is a code section for each spectrum. This is an output information combining unit that combines the respective outputs of the spreading modulation units 71 and 72. In addition, other Figure 4
Blocks that are the same as those shown in are given the same symbols,
The redundant explanation will be omitted.

Next, the operation will be explained. The basic operation is the same as the conventional one, but within the transmission system 1, the information transmission system 3 and the deception transmission system 4 are not separated, and the spread spectrum modulation section is time-divisionally used for information and deception purposes. ing. That is, in the transmission system 1, the information 5 is an analog audio signal, an analog/digital converted digital signal, or a data signal. In wireless communication, the information 5 is a low frequency signal and cannot be transmitted as is.
A change corresponding to the information 5 is applied to a high frequency signal previously created by the information modulation section 6. The carrier wave modulated according to the information 5 by the information modulator 6 has its spectrum spread by spread spectrum modulators 71 and 72 in the same manner as described above. The code sections 81 and 82 are used to discretely switch the frequency of the carrier wave (modulated wave) modulated according to the information 5 by the information modulation section 6 in a certain pattern by the spread spectrum modulation sections 71 and 72. Create a hopping pattern.

The switching section 16 also selects and connects any one of the plurality of spread spectrum modulation sections 71 and 72, and outputs a carrier wave (modulated spread spectrum modulation units 71, 7
Transmit to 2. For example, if the spread spectrum modulation section 71 is selected by the switching section 16, the spread spectrum modulation section 72 will operate for deception. on the other hand,
The receiving system 2 is no different from the conventional one, and restores the original information 5 in synchronization with the frequency hopping pattern of one of the spread spectrum modulators 71 and 72 selected for information.

In the above embodiment, two sets of spread spectrum modulation sections 71, 72 and code sections 81, 82 are provided, but three or more sets may be provided as shown in FIG.

Furthermore, in the embodiments shown in FIGS. 1 and 2, the receiving system 2 has been described as having the same configuration as the conventional one, but as shown in FIG. Synchronization parts 121 to 12 of the same group as
3 are provided, respectively, to create the same hopping pattern as each code of the transmission system, and the switching unit 16 selects a synchronization part having the same hopping pattern as the code part selected by the transmission part 1 for information use, and then generates a local oscillation. By controlling the signal and demodulating it in the spread spectrum demodulation section 11, it is possible to provide further flexibility in the operation of spread spectrum communication.

[0021]

As described above, according to the present invention, there are provided a plurality of spread spectrum modulation units that discretely switch and sweep the frequency of a modulated wave obtained by an information modulation unit in a fixed pattern, and a plurality of spread spectrum modulation units that a code section that is connected to each of the plurality of spread spectrum modulation sections to create a frequency hopping pattern for the switching; and a code section that is connected to each of the plurality of spread spectrum modulation sections and selects the information of the modulated wave obtained from the information modulation section in a time-division manner to one of the plurality of spread spectrum modulation sections. and a switching unit that enables the selected spread spectrum modulation unit to operate as information use and the other spread spectrum modulation units as deception use; Since the structure is configured so that it can be combined and transmitted to the receiving system, the conventional work that the user would have to do to reset the synchronization timing every time the frequency hopping pattern is changed can be reduced to just a switching operation, and it also eliminates the confidentiality characteristic of spread spectrum communication. This has the effect of providing flexibility in operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a frequency hopping spread spectrum communication device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing another embodiment of the transmission system in the present invention.

FIG. 3 is a block diagram showing another embodiment of the receiving system according to the present invention.

FIG. 4 is a block diagram showing a conventional frequency hopping type spread spectrum communication device.

FIG. 5 is an explanatory diagram showing spread spectrum modulated waves for information and deception in FIG. 4;

[Explanation of symbols]

2 Receiving system 5 Information 6 Information modulation section 9 Output information synthesis section 16 Switching section 71 Spread spectrum modulation section 73 Spread spectrum modulation section 81 Code part 82 Code part

Claims (1)

[Claims] Claim 1: An information modulation unit that modulates a carrier wave according to information to be transmitted, and a plurality of spread spectrum modulation units that discretely switch and sweep the frequency of a modulated wave obtained by the information modulation unit in a fixed pattern. a coding section that is connected to each of the spread spectrum modulation sections and creates a frequency hopping pattern for the switching; and a coding section that is connected to each of the spread spectrum modulation sections and generates a frequency hopping pattern for the switching, and transmits the information of the modulated wave obtained by the information modulation section to the plurality of spread spectrum modulation sections. a switching unit that selectively supplies the spread spectrum modulation unit to any one of the above in a time-sharing manner to enable the selected spread spectrum modulation unit to operate as information use and the other spread spectrum modulation unit to operate as deception use; an output information synthesis section that synthesizes the output information of the modulation section to enable transmission; and an output information synthesis section that receives the transmitted output information and synthesizes the output information in synchronization with the frequency hopping pattern of the spread spectrum modulation section selected for the information. A frequency hopping type spread spectrum communication device comprising a receiving system for restoring information of the frequency hopping method.