RU2308049C1 - Method for creating non-modulated active interferences for suppressing mobile communications under conditions of multipathing of interference and signal - Google Patents

Abstract

FIELD: radio-electronic suppression of radio-electronic devices.

SUBSTANCE: method for creating non-modulated active interference for suppressing mobile communications under conditions of multipathing signal and interference includes receiving signals of device being suppressed, creating and emitting continuous interference signal at working frequency of the device being suppressed by means of an antenna. Antenna is turned around a circle, radius of which equals λ/4, where λ - wave length of interference signal. The method allows prevention of interference fading of interference field in receipt points, ensures expansion of guaranteed mobile communications suppression zones, and reduction of energy costs of suppression.

EFFECT: realization of method for creating non-modulated active interferences for aimed setting of interference for mobile communication means under conditions of multi-path distribution of radio waves.

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Description

The invention relates to the field of radio engineering, and in particular to the field of electronic suppression (REP), electronic means (RES), and can be used for targeted jamming of mobile communications in the conditions of multipath propagation of radio waves.

There is a method [1, p.12, 13] of suppressing a RES with a frequency-targeted interference using a jamming station (SP) with a frequency-tunable narrow-band interference. The SP formed by the frequency-targeted narrow-band noise in its parameters is consistent with the tuning frequency and bandwidth of the receiver of the suppressed ES and is characterized by a high power spectral density.

The closest in technical essence (a prototype of the claimed invention) is a method of creating unmodulated active radio interference [1, p.13-15]. The essence of the method lies in the formation and emission of continuous harmonic oscillations at the tuning frequency of the suppressed RES. The method is implemented using a joint venture, the structural diagram of which is shown in Fig. 2.11 [1, p. 34], and a description of the joint venture is shown on pages 34-35 [1].

To suppress communication, it is necessary to fulfill the condition that the interference / signal ratio exceeds the suppression coefficient K _n at the input of the receiver of the mobile station (MS)

where P _{n, c} is the interference power of the signal at the input of the receiver of the MS, respectively.

As is known [2, pp. 50-51], the propagation of radio waves in urban environments and inside buildings is accompanied by multipath, which leads to significant changes in the field levels (up to 40 dB) of the signal and interference within a relatively small spatial area. Knowing this feature of multipath propagation of radio waves, the subscriber of the MS, having determined that his MS is suppressed, begins to search in space for a point at which the required signal / noise ratio is observed. Thus, even if condition (1) is fulfilled for medium levels of interference and signal, at some points inside the building, the communication will function with the required quality, which is a significant disadvantage of the prototype. The disadvantage of the prototype is the need to increase the radiation power of the SP in order to compensate for the deep fading of interference at the reception points.

The problem to be solved by the claimed method is aimed at eliminating constant in time deep interference fading of the interference field at the receiving points.

The technical result is expressed in reducing the radiation power of the SP, necessary for guaranteed suppression of MS in a given region of space. By guaranteed, we mean a suppression in which there are no points with an acceptable quality of communication in the suppressed region of space.

The technical result is achieved by the fact that in the known method of creating unmodulated active interference, which consists in receiving an MS signal, generating and emitting a continuous interference signal with an antenna at its operating frequency, the antenna rotates around a circle whose radius is λ / 4, where λ is the length wave interference signal.

The essence of the proposed method is as follows.

In the known method, the generated noise is emitted by an antenna located at one point in space, so the propagation path of the SP-MS does not change over time if the MS is stationary. When a subscriber moves with the MS in the suppression area, points can be found at which a minimum of interference is observed, and the communication quality will be acceptable.

. Видно, что за один период вращения антенны Т значение q_н может изменяться до 40 дБ. В этом случае абонент МС не может найти точки с постоянным минимальным уровнем помехи.In the proposed method, the SP antenna is constantly moving in space, while the interference radiation at each moment in time comes from different points in space. The propagation paths of the interfering signal change, therefore, the level of interference at the input of the MS receiver also changes, even if it is stationary. Consider one of the most easily implemented in practice options for moving the antenna of the SP - rotation around the radius R.

. It can be seen that for one rotation period of the antenna T q _n value can vary up to 40 dB. In this case, the subscriber MS can not find points with a constant minimum level of interference.

The proposed method can be implemented using a device whose structural diagram is shown in figure 3.

The device contains:

- equipment for detection and analysis of signals 1;

- interference shaping device 2;

- transmitter interference / interference 3;

- control equipment 4;

- omnidirectional mobile antenna 5;

The jamming station that implements the inventive method operates as follows.

Formed in the jamming device 2 and in the interference transmitter 3 unmodulated interference emitted by an omnidirectional mobile antenna 5.

The control equipment 4, on the basis of data from the equipment for detecting and analyzing signals 1, depending on the parameters of the processed signals, selects the most optimal operating modes of the joint venture.

Example. To verify the applicability of the claimed invention, experimental studies were conducted to assess the changes in the level of the interfering signal when moving the SP antenna along a circle of radius R. Figure 1 shows a diagram of rooms on one floor of a building in which a SP, transmitting MS and receiving (suppressed) MS are located.

As an interference transmitter, the G4-129 generator tuned to a frequency of 900 MHz was used. The receiver was a SMV-8.5 selective microvoltmeter. As transmitting and receiving antennas, half-wave symmetrical vibrators were used.

. На фиг.2 время t_Σp соответствует заштрихованной площади. Как известно, для потери информации необходимо накрытие помехой половины слова, что соответствует W=0.5. Отметим, что для случая использования неподвижных антенн коэффициент W может принимать только два значения - 1 (связь подавлена) и 0 (связь неподавлена).The evaluation results showed that when the SP antenna moves around the circumference, the level of the interfering signal at the receiver input changes by a value of the order of 20-30 dB, while the radius of the circle should be at least λ / 4, where λ is the wavelength of the interfering signal. In addition, the SP antenna must rotate at a sufficiently high speed so that the rotation period is not more than the average word duration. In this case, all words will be distorted, and, as a result, the information will be lost. We introduce the coefficient W equal to the ratio of the time during which communication is suppressed to the period of rotation of the antenna

. 2, the time t _Σp corresponds to the hatched area. As is known, to lose information, it is necessary to cover half the word with interference, which corresponds to W = 0.5. Note that for the case of using fixed antennas, the W coefficient can take only two values - 1 (communication is suppressed) and 0 (communication is not suppressed).

Let us estimate the gain in power of application for the joint venture of mobile antennas in comparison with stationary ones.

, равному 12 дБ, фиг.4в - значению

, равному 27 дБ.Figure 4 shows the dependence of the coefficient W when moving the MS along the 0y axis (a - a mobile antenna is used; b, c - a stationary antenna). Figa, b corresponds to the average for the suppressed region the value of the normalized ratio of interference / signal

equal to 12 dB, figv - value

equal to 27 dB.

, равном 12 дБ, абонент МС не сможет найти точки с приемлемым качеством связи (гарантированное подавление области пространства). При использовании неподвижной антенны (фиг.4), точки с приемлемым качеством связи в этом случае могут быть найдены, кроме того, в этих точках коэффициент K равен 0 (искажение информации вообще отсутствует). Даже при увеличении отношения

до 27 дБ (фиг.4в) в подавляемой области пространства могут быть найдены точки с приемлемым качеством связи. При дальнейшем увеличении отношения

подавление данной области пространства будет гарантированным. Нетрудно заметить, что при использовании для СП подвижной антенны, перемещающейся по окружности радиусом λ/4, выигрыш по мощности составляет порядка 15 дБ по сравнению с использованием для СП неподвижных антенн.From figure 4 it is seen that when using a mobile antenna for the SP at a value

equal to 12 dB, the subscriber of the MS will not be able to find points with an acceptable quality of communication (guaranteed suppression of the area of space). When using a fixed antenna (figure 4), points with acceptable communication quality in this case can be found, in addition, at these points the coefficient K is 0 (there is no information distortion). Even with an increase in attitude

up to 27 dB (figv) in the suppressed region of space can be found points with acceptable communication quality. With a further increase in attitude

suppression of this area of space will be guaranteed. It is easy to notice that when using a mobile antenna for a SP moving around a radius of radius λ / 4, the power gain is about 15 dB compared to using fixed antennas for a SP.

Thus, when using mobile antennas for SP in the suppressed region of space, there are no points with clear dips in the interference field. The interference field in the suppressed region is constantly changing, and at a speed equal to the speed of the PP antenna. This makes it impossible for the subscriber of the MS to adapt to the interference environment by searching for points of space with a minimum level of interference.

The proposed technical solution is new, because from publicly available information there is no known method for creating unmodulated active interference, based on the emission of an interfering signal by an antenna rotating in a circle whose radius is λ / 4.

The proposed technical solution has an inventive step, since it does not explicitly follow from published scientific data and known technical solutions that the inventive method for generating unmodulated active interference by emitting an interference signal by an antenna rotating around a circle whose radius is λ / 4 reduces the minimum required for guaranteed suppression of this MS power PP.

In practice, the inventive REP method can be implemented using commercially available radio equipment devices.

The inventive method of creating unmodulated active interference to suppress mobile communications inside the building allows in practice to significantly reduce the required radiation power of the SP or to increase the range of MS suppression inside the building.

Information sources

1. Paly A.I. Electronic warfare. - M .: Military Publishing House, ed. 2nd, rev. and add., 1989, pp. 12-15, 34-35.

2. Lee W. Technique of mobile communication systems: Per. from English - M .: Radio and communications, 1985, p. 50-51.

Claims (1)

The method of creating unmodulated active interference to suppress mobile communications in the conditions of multipath signal and interference, according to which the signals of the suppressed means are received, a continuous interfering signal is generated and emitted by the antenna at the operating frequency of the suppressed means, characterized in that the antenna rotates around a circle whose radius is λ / 4, where λ is the wavelength of the interfering signal.

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