WO2015086690A1 - Jamming method and device with confined linear effect - Google Patents

Abstract

A confined jamming device and method arranged in a coverage area in which may be found prohibited radio communication devices the operation of which it is sought to be prevented, characterized in that said device comprises at least the following elements: • at least one linear element (1) comprising a plurality of openings Oi enabling interference signals to be radiated, the linear aerial being connected to one or more effectors via a connector (3), · said generating effector element or elements (2) being suitable for injecting one or a plurality of interference signals at at least one end of the linear aerial (1), the power flux Ρ_j,f of the interference signal J_j,f in the band B_j,f of a carrier f is selected such that the ratio P_Sj,f/P_J,f, between the power flux P_Sj,f of the signal S_j,f potentially usable by the prohibited device on the carrier f and the power flux P_J,f, of the signal J_f present on the carrier f for preventing operation of the prohibited device are less than an operating threshold Seuil_Sj,t of the prohibited device.

Description

 METHOD AND INTERFERENCE DEVICE WITH CONFINED LINEAR EFFECT

The invention relates to a method and a scrambling device using an overhead line and a scrambling device, the assembly being adapted to generate and broadcast disturbing or jamming signals in a given closed or semi-open space without impact on the operation. elements arranged outside this space.

 It finds its application to disrupt or prevent the operation of radio systems, radiocommunication devices, the use of which is illegal, or radio systems that do not have operating authorization, in enclosures, prisons, cinemas examination, etc.

 In certain environments such as prisons, examination centers, schools, some rooms in embassies, experimental centers, etc., the use of radio communication devices, such as mobile phones, is prohibited. One of the problems today is to eradicate all unauthorized radiocommunications in a closed enclosure by controlling the containment of the signal used to prevent such communications by avoiding any inconvenience to outside users not concerned by this prohibition of radiocommunications.

The state of the art known to the applicant describes detection systems and jamming systems that will block the illicit radio communications and the systems that use them from conventional radio antennas. These devices have many disadvantages; due to geometric losses in 20.log-i ₀ (R) of the power radiated from a conventional antenna (where R is the distance to the phase center of the antenna), they are poorly suited in terms of efficiency, coverage , of emitted power; the containment is not satisfactory, which generates complaints from operators and external users not affected by this prohibition; they are very delicate to install and maintain, and often expensive as soon as significant hedges have to be obtained.

 US Patent 6,195,529 discloses a method and device for blocking the transmission of mobile phones by transmitting interfering signals in the frequency range of the mobile radio.

 The document entitled "Jamming System for Mobile Communications" of POUSADA-CARBALLO et al., Electronics Letters, IEE STEVENAGE, vol. 34, No. 22, XP00601536, describes a scrambling system for communications in a closed area, generating signals of noise at the transmission channel corresponding to the signal to be scrambled.

 Patent application WO 98 56192 describes a method for regulating cellular communications.

 There is at present a need for a device allowing complete jamming of radio communications considered to be illegal, which device applies within a given closed space in general (or known as "space"). indoor "), whose effectiveness is reliable, controlled coverage, confined effect, and controlled containment. The term "unlawful or prohibited terminal" means a terminal, a radiocommunication device that is not authorized to operate in a given area and outside that perimeter.

 We shall use indifferently the expression "linear element" or "linear air" to designate the same element.

 The object of the invention is based in particular on the use of one or more linear geometry airplanes associated with effectors consisting of suitable scrambling devices and couplings. The use of these effectors and the linear geometry of the aerial allow both:

 • ensure reliable coverage of interference,

 • control the jamming confinement,

• simultaneously transmit numerous interference signals simultaneously addressing a large number of frequency intervals and a large number of radio systems whose frequency plans are included in these ranges.

 The invention relates to a confined interference device disposed in a coverage area in which there may be prohibited radio communication devices whose operation is sought to prevent, characterized in that it comprises at least the following elements:

 At least one linear aerial comprising several orifices Oi allowing the radiation of interference signals, the linear aerial being connected to one or more effectors via a connector,

The one or more effectors being adapted to inject one or more interference signals at one end of at least one of the linear overhead signals, the power flow Ρ of the interference signal J _jif in the band Β of a carrier f is chosen such that the ratio Ps, j / Pj, f, between the power flow Ps _j of the signal S _j , f potentially usable by the forbidden device on the carrier f and the power flow Pj _{, f} , of the signal J _f present on the carrier f to prevent the prohibited device from operating is below the operating threshold Thresholds _j .t of the forbidden device (Psj / Pj, f≤ Thresholds.t).

 According to an alternative embodiment, the effector is adapted to generate, for a point M (r, l) in which a forbidden radiocommunication device is located, a value of the spectral density Ν (Γ, Ι) of the interference signal injected into the linear overhead via the connector such as for the band B ,, f of each carrier f on

10.log ₁₀ (Nj, _f (r, l) .Bi, _f )> 10.log ₁₀ (Ps, j, t) -10.log ₁₀ (Thresholds, j, f) + C (r ₀ ) +

P '. (Ll ₀ ) + 10.log ₁₀ (r / r ₀ ) + where

. r, I, are the coordinates of a point M,

. I ₀ denotes a reference linear distance, r ₀ denotes a reference radial distance to the linear element,

. P 'denotes the rate of linear losses along the aerial radiating from the distance l ₀ , . -C (ro) denotes the losses by coupling in the band Bj at the reference radial distance r _0,

 . η represents a margin of caution taking into account additional attenuations of the jamming signal during its propagation from the air to the forbidden terminal.

 The effector is, for example, adapted to generate transmission power taking into account one or more of the following elements:

 - measurements of the beacon, control and traffic signal levels from transmitters in the external networks which may enter into communication with the illicit devices,

 the rate P 'of linear losses in the linear air,

losses by coupling C (r ₀ ) of the linear overhead,

 margins η intended to compensate for the additional attenuations of various types which may affect the jamming signal J during its propagation from the linear overhead line to the device to be scrambled.

 According to one variant, the characteristics of the prohibited radiocommunication devices and the characteristics of the aerial radiation regime are previously known or measured in order to parameterize and adjust the frequency bands of the interference signal, the nature of the jamming signals emitted and the levels at the output of the effector whose signal is injected into the air via the coupler.

 At least one of the effectors is, for example, adapted to the generation and transmission of scrambling signals, and is a broadband generic scrambler.

 The effector is, for example, adapted to the generation and emission of jamming signals and is composed of a set of dedicated jammers, whose output signals are transmitted to filtering and amplification and rectification modules, then injected into a coupler, the output of said coupler being injected into the linear aerial.

According to one variant, the effector is, for example, adapted to the generation and transmission of jamming signals and comprises modules frequency-selective filtering apparatus adapted to excise the scrambling signal to release one or more carriers usable by a controlled radiocommunication over-network.

 The device may comprise means adapted to duplex the signal at the output of an effector and a device for injecting said signal into two different linear aerials.

 The device may also comprise a first effector disposed at a first end of the linear overhead and a second effector disposed at a second end of the linear overhead line in order to inject a jamming signal J1, J2 at each end of the linear air.

 The device may include a system of baffles adapted to locally optimize the confinement, baffles for which one can use grilles for passage of electric cables with inverted mounting, mesh meshes and various geometries.

 The invention also relates to a method of interference jamming the operation of one or more radiocommunication devices prohibited in a given zone, implemented in the device having one of the preceding characteristics, the method is characterized in that it has at least the following steps:

 · Using at least one linear aerial comprising a plurality of orifices Oi allowing the radiation of jamming signals, the linear aerial being connected to one or more effectors via a connector,

• injecting at least one of the linear aerial one or more interference signals, the power flow Ρ of the jamming signal J _{j, f} in the band B _jf of a carrier f is chosen such that the ratio

Psj, f / Pj, f, between the power flow Ps .t of the signal Sj, f potentially usable by the forbidden device on the carrier f and the power flow Pj _{, f} , of the signal J _f present on the carrier f for to prevent the prohibited device from operating is below the operating threshold Thresholds of the forbidden device (Psj / Pj, f≤ Thresholds.t). For the implementation of the method, a value of the spectral density N _jf (r, l) is generated for the interference signal injected into the overhead line, such as for the band B _if of each carrier f

10.logio (N _j, f (r, l) .B _i, f)> 10.log ₁₀ (Psj, _f) -10.logio (threshold _s, j, f) + C (r ₀₎ +

 . r, I, are the coordinates of a point M,

. I ₀ denotes a reference linear distance,

. r ₀ denotes a reference radial distance to the linear element,

. P 'denotes the rate of linear losses along the aerial radiating from the distance l ₀ ,

. -C (r ₀ ) denotes the losses by coupling in the band Bj at the reference radial distance r _0,

 . η represents a margin of caution taking into account additional attenuations of the jamming signal during its propagation from the air to the forbidden terminal.

 Other characteristics and advantages of the method and of the device according to the invention will appear better on reading the following description of an exemplary embodiment given by way of illustration and in no way limiting attached to the figures which represent:

FIG. 1, an exemplary device according to the invention comprising a linear element at the input of which a scrambling device injects a scrambling signal dedicated to the eradication of unauthorized radiocommunications,

 FIG. 2, a linear element detail,

FIG. 3a, an example of an arrangement of a linear element provided at each of its ends with an effector and implemented in a space with a privileged direction,

FIG. 3b, a possible example of an arrangement of several linear elements for the implementation of the method in a closed space of rectangular or square shape whose linear elements define the perimeter, in which the jamming signal, emanating from two effectors present at the ends of a diagonal, is distributed in each half-perimeter,

• Figure 4, a representation of a linear element with an effector connected to each end.

 In order to better understand the object of the invention, the description is given for illustrative and not limiting purposes for an application to prevent the operation (transmission / reception) of a mobile phone whose use is prohibited within 'a prison, that is to say that we will ensure that the signaling signals to this mobile phone can not be decoded or interpreted by the latter, which makes it impossible for any access to the network any request for a call or any answer to the calls. This example can be extended to all radio devices whose operation is not allowed in a given space.

 FIG. 1 schematizes a first exemplary embodiment of the device according to the invention comprising an overhead with linear geometry 1, associated with a device for generating disturbing waves or effector 2, via a connector 3. The mobile telephone 4 which is not Not allowed to receive communications or data is found on this figure in the vicinity and in the efficiency zone of the linear overhead.

 The effector 2 is for example composed of:

 one or more devices for generating and transmitting interference signals 5, 5 ',

 one or more filtering modules and amplification and rectifying stages 6, 6 ', signals emitted by the aforementioned generation and transmission devices, these filtering and amplification modules making it possible to finely adjust the bands, the carriers and the output levels,

 a coupler 7 making it possible to constitute the signal effectively injected into the linear aerial 1 via the connector 3.

Such an arrangement makes it possible to produce a broadband interference signal or a multi-band interference signal, of frequency bands, carriers and adequate levels in given areas where mobile phones 4 that are sought to prevent operation can be found. In practice, the scrambling signal is injected into the linear overhead via the connector 3 with a level adjusted on each band and on each carrier in these bands to scramble and prevent on these carriers all data exchange between the mobile terminal and prohibited communications networks throughout the area covered by linear overhead. That is to say that in the example of FIG. 1, the resulting jamming signal J, considered at the forbidden terminal, has, for each of the carriers potentially usable by the forbidden terminal, a power Pj defined as a function of the power P _s of the signals listened to by the forbidden terminal, such that the PS / PJ ratio is less than the operating threshold Thresholds of the prohibited mobile phone on each usable carrier (this operating threshold Thresholds being known to those skilled in the art for each radio network to be forbidden by consultation of the standards of these networks).

 The aerial linear geometry 1 has for example radiation characteristics which, combined with suitable effectors as described above, can disrupt the operation of mobile phone present at the point M (r, l) by precisely controlling the flow the radiated power Pj (r, l) as a function of the linear distance I and the radial distance r which define the positions M (, l) of one or more illicit devices (ie the positions of the mobile telephones 4 in the area covered by linear overhead). The linear distance I is defined, for example, with respect to the connector 3 of the linear element. The radial distance r is determined by the measurement of the perpendicular to the linear element which meets the point M (r, l), for example.

More precisely, the radiated interference power flow Pj (l, r) by the aerial in a scrambled band Bj at the point M (r, l) indicated by the linear distance I and the radial distance r, is given in decibel ( dB) by the "cylindrical" radiation regime expressed by the following formula: 10.logi (Pj (l, r)) = 10.logi ₀ (Po (lo)) - C (r ₀ ) - P '. (LI ₀ ) - 10.logi ₀ (r / r ₀ ) (1) . Where I denotes the linear distance,

. r designating the radial distance to the linear element,

. I ₀ denoting a reference linear distance (in general the man of the art considers l ₀ as zero or very weak and corresponds to ₀ for example the output of the coupler 7) and P ₀ (lo) designating the corresponding power in the band Bj resulting from the injection of the jamming signal into the aerial via the connector 3,

. P 'denotes the rate of linear losses along the aerial radiating from the reference linear distance l ₀ (assumed loss, to simplify rewrite but without limitation of generality, constant in the band Bj, itself supposed to be sufficiently narrow ); this value is a manufacturer datum in general or a quantity paired by the measurement in each of the bands Bj, this value is at most a few dB per 100 m of propagation in the air,

. r ₀ denoting a reference radial distance to the linear element (generally those skilled in the art consider r ₀ = 2 m),

. -C (r ₀ ) designating the coupling losses in the band Bj at the reference radial distance r ₀ ; (-C (r ₀ ), constructor data in general, or paired by measurement, has a value of the order of -55 dB at -70 dB at radial distance of reference r ₀ = 2m, homogeneous over the length of the air),

. Pj (1, r) is the power flow in the band Bj of the signal J at the point M (r, l). In the case where there are several interference signals, the power Pj considered is global and can correspond to several sub-bands (in this case what counts for the interference efficiency is Ps / PJ <Thresholds in the previously noted band Bj of the carrier of S).

 In the wording (1) above:

. the rate of linear losses P 'by propagation in the air is low, which guarantees a uniform level of aerial radiation over the lengths targeted by the invention, the linear distance typically satisfying the [l ₀ , L];

L <100 m, . the cylindrical regime (expressed in dB by -10.logi ₀ (r / rO) in the formulation (l)) of the radiation propagation losses depends linearly on the inverse of the radial distance r at the linear plane and not quadratically of the inverse of the distance R (real distance / phase center) absolute at the center of phase of the aerial as in the case of conventional systems described in the state of the art.

 The dimensions of the linear air element, its diameter Φ, its length L and its orientation with respect to the geometry of the zone to be covered, as well as the distribution of the orifices Oi allowing the diffusion of the interference signals J and the positioning of possible baffles to facilitate the confinement are chosen in particular according to the radiocommunication devices whose operation it is desired to eradicate, and the geometry of the zone in which it is desired to eradicate the operation of illicit radiocommunications.

 When the area to be covered has privileged directions

(corridors, corridors) as in Figure 3a, the orientation of the linear elements is performed for example tangentially to these privileged directions. When the area to be covered is a closed enclosure without privileged direction, as in Figure 3b, the aerials are arranged for example tangentially to the edges of this enclosure.

 The emission powers of the effector 2 are adjusted, for example taking into account one or more of the following elements:

 - measurements of the corresponding field levels coming from the transmitters 8, 9, 10, 1 1 present in the external networks and likely to communicate with the illicit terminals whose radiocommunications are to be eradicated, and

 the linear loss regime explained by formula (1) above, and

- Margins η intended to compensate for additional attenuations of various kinds which may affect the jamming signal J during its propagation from the linear airborne 1 to the transmitting device to scramble, 4, (walls, doors, human body , etc.). The objective is to obtain a jamming signal J at least such that, in each band B _j j = 1 ... J and for each beacon or control channel f in each band B _j corresponding to the external transmitters likely to enter into communication with the illicit transmitter / receiver terminals whose radiocommunications are to be eradicated, the power flow Ρ of the jamming signal J _jif in the band B _jf of the carrier f is such that the signal S _{j, f} potentially usable by the forbidden terminal (index i) on the carrier f, power flow Ps, i, f, is received with a ratio Ps, i / Pj, f lower than the operating threshold Thresholdj.t of the forbidden portable terminal (this threshold operating threshold _Sj , f being known to those skilled in the art for each radio network and for each type of carrier beacons f to prohibit, by consulting the standards of these networks). Or again, the ratio Psj, f / Pj, f, between the power flow Ps .t of the signal Sj, f potentially usable by the forbidden device on the carrier f and the power flow Pj _{, f} , of the signal J _f present on the carrier f to prevent the forbidden device from operating is less than the operating threshold Thresholds of the forbidden device (Ps, j, f / Pj, t≤ Thresholds.t) - This is written in decibels:

10.log-i ₀ (Ps, j, f) - 10.log-i ₀ (Pj, f) ≤ 10.log-i ₀ (Thresholds, j, f) in the band B _{i: f} of the carrier j , f, j being the index of the band of the terminal, that of the carrier, or else:

10.logio (Pj, t) ≥ 10.logio (Psj, f) - 10.log-i ₀ (Thresholds, j, f) in the band B ,, f of the carrier f

Considering a terminal forbidden at the point M (r, l), the spectral density N _j , f (r, l) of the interference signal injected into the linear overhead via the connector 3 must therefore verify for the band B ,, f of each carrier f:

10.logi (Nj, f (r, l) .Bi, f) -C (r ₀ ) -P '. (L-lo) -10.logio (r / r ₀ ) ≥10.logi ₀ (Psj, f) -10.logio (Threshold _SJ , f) + again:

10.log ₁₀ (Nj, _f (r, l) .Bi, _f )> 10.log ₁₀ (Psj, f) -10.log ₁₀ (Thresholds, j, f) + C (r ₀ ) +

P '(ll ₀ ) + 10.logio (r / r ₀ ) + (2) where η represents a certain margin of precaution to take into account additional attenuations of the jamming signal during its propagation from the air to the forbidden terminal 4.

This condition expressed in the formula (2), to be verified for a zone defined by a radius r ₀ ≤r <r _max , lo ll≤ L _max a sufficient condition is to check it for r = r _max , l = L _max , r \ = r \ _ma *

10.logi (Nj, f.Bi, f) ≥1 0.log ₁₀ (Psj, _f ) -1 0.logi ₀ (Thresholds, j, f) + C (r ₀ ) + P '. (L _max - lo)

+1 0.log ₁₀ (r _max / r ₀ ) + r | ma _X (3).

The illustrative and nonlimiting example of FIG. 1 shows radio communication signals S ₈ , S ₉ , S-10, Su coming from external transmitters 8, 9, 1 0, 1 1 in bands B ₈ , B ₉ , B ₀ , Bu _, the transmitters being likely to enter into communication with the illicit terminal 4 of which it is desired to eradicate radiocommunications. For this configuration, if we consider a beacon carrier or external transmitter control, at carrier frequencies respectively denoted f ₈ , f ₉ , fm, fn, and bands respectively denoted Bj _{! 8} , Β ^ ₉ , Bjjo, Bj .n, if we note P _s , ₈ Ps, g Ps, io Ps, n the corresponding power flows received by the illegal terminal 4, if we note Thresholds. Thresholds. Thresholds.io Thresholds.n operating points (known to those skilled in the art) of the illicit terminal 4 in the bands B _{J 8} , Bj _{, 9} , Bj ₀ , Bj _, ii of the carriers f ₈ , f ₉ , f ₀ , fn, the signal levels minimum interference Pj, ₈ Pj, ₉ PJ O Pj, n which must be received by the illegal terminal 4 in the bands Bj, ₈ , Bj, ₉ , Bj, - | ₀ , Bj, n satisfy the following conditions

 In real quantities:

Ps, s / Pj, s≤ Threshold _s , s in the band B _{J 8} of the carrier f ₈ Ps, g / Pj, g ≤ Thresholds in the band Bj _{! 9} of the carrier f ₉

Ps, io / PJ, IO≤ Thresholds in the band Bj, i ₀ of the carrier fm Ps, ii / PJ, II ≤ Thresholds, ii in the band Bj, n of the carrier fn In decibels:

10.logio (Pj, ₈ ) ≥10.logio (Ps, 8) -1 0.logio (Thresholds, ₈ ) in the band Bj, ₈ of the carrier f ₈ 10.logio (Pj, 9) ≥10.logio (Ps, 9) -10.logio (Thresholds, 9) in the band Bj, ₉ of the carrier f ₉

10.log o (Pj, io) ≥ 0.log ₀ (Ps, io) - 0.log ₀ (Thresholds, io) in the band B _{Ji 0} of the carrier fi ₀

10.logio (Pj, n) ≥10.logio (Ps, ii) -10.logio (Thresholds, ii) in the band Bj, n of the carrier fn _, and this,

 on the area covered by the linear overhead.

It can be deduced that the injected power spectral density levels N _s , s N _s , g N _s , io N _s , n in the linear overhead via the connector 3 must verify the following conditions in decibels:

10.log ₁ o (N _J , ₁₁ (r, l) .B _J , ₁₁ )> 10.log ₁ o (Ps, ii) -10.log ₁ o (Thresholds, ii) + C (r ₀ ) + P '. (l-lo)

+ 10.logio (r / r ₀ ) + Ti ii

1

0.log ₁₀ (P _s , io) -10.log ₁₀ (Thresholds, io) + C (r ₀ ) + P '. (L-lo)

10.log ₁₀ (Nj, ₉ (r, l) .bj, _9)> 10.log ₁₀ (Ps, 9) -10.log ₁₀ (Thresholds, 9) + C (ro) + P '. (L- lo)

+ 10.log ₁₀ (r / r ₀ ) + r | ₉ 10.logio (Nj, ₈ (r, l) .bj, _8)> 10.logio (Ps, e) -10.logio (threshold _s, 8) C + (r ₀₎ + P '. (L- lo)

+ 10.log ₁₀ (r / r ₀ ) + r | ₈ where η ₈ η ₉ η ₁₀ η _η represent certain precautionary margins to take into account additional attenuations of the jamming signal during its propagation from the aerial to the forbidden terminal 4 in the bands B ₈ , B ₉ , Bm, Bu .

The effector device 2 for generating and transmitting the jamming signals is composed, for example, of a generic broadband jammer or of a set of jammers each dedicated to one of the radio communication networks prohibited in the zone. covered, amplitude-adjusted where appropriate, and whose outputs are coupled according to methods well known to those skilled in the art before injection into the linear air so as to treat several bands B _j and multiple carriers f _j simultaneously. Its characteristics are, for example, chosen according to the illicit devices likely to be in a supervised area. This allows somehow to build an effector "à la carte" specifically adapted to the processed radio configuration and to networks whose communications must be locally neutralized.

 For example, it is possible to use dedicated second, third and fourth generation radio-cellular jammers, GPS (Global Positioning System) jammers operating the industrial ISM band (Industrial, Scientific and Medical). ) (Bluetooth short radio type, or following WiFi wireless protocol), etc. (see Figure 1, 5 and 5 '). These dedicated jammers have low power per subband (<1 W), low cost (odg <100 $ unit x a few units per device).

 It is also possible to use an additional device adapted to straighten power levels by amplification and dedicated filtering of each subband to compensate if necessary a frequency dispersion of the necessary emission levels (see Figure 1) and in particular:

 - an inhomogeneity of cable losses as a function of the frequencies (dispersive linear overheads),

- an inhomogeneity of the signal levels S ₈ , S ₉ , Sm, Su received by the illicit radio systems and that one wants to scramble.

 According to another variant embodiment, frequency excision, a method known to those skilled in the art, of one or more carriers in the scrambling signal by a filtering adapted at the level of the amplification and rectification stages (6, 6 '), so as to allow the use of these carriers for radio controlled by the system operator, emergency calls, authorized on-network radiocommunications, etc.

 The method according to the invention associated with the example of FIG. 1 comprises, for example, the following steps:

 1) to define the arrangement of line-spacecraft in a zone to be controlled in which illicit radiocommunications must be prevented,

2) define parameters for an interference signal: frequency band, interference power flow levels in the area to be controlled expressed as a function in particular of the radial distances of the various points of the zone with linear airs arranged to cover said zone, measurements of field levels or of the aforementioned elements,

 3) to emit a power signal adapted to scramble the illicit devices present in the controlled zone from the linear aerials which are arranged therein, the signal level being such that the ratio between the operating power flow of the illicit device and the flow interference signal power is less than the operating threshold value of the illicit device.

 Figure 2 is a detail of an example of a linear cable comprising a plurality of orifices arranged to allow the passage of interference waves in the area to be monitored. The linear air comprises several orifices Oi distributed along the element according to the desired application, the orifices are separated by sections 21 which do not allow the passage of jamming signals.

 FIG. 3a schematizes an alternative embodiment of the invention in a corridor-type preferred direction enclosure in which a single element 301 has been installed at a ceiling and two effectors 305 306 at the opposite ends of the ceiling. element, as described above.

The orifices of the linear element allow the emission of interference signals Ji, J ₂ , the mobile phone 4 located in the corridor can not decode the signals emitted by exteriors. The parameters of interference, power levels, will be selected in particular according to the linear arrangement of these linear elements.

FIG. 3b schematizes an alternative embodiment of the invention in an enclosure having no privileged direction, in which four linear elements 31 1, 312, 313, 314, of length L ₂ , Li, L ₂ , respectively, have been installed. , L _; at the unrepresented walls of a piece of square geometry to monitor and two effectors 315, 31 6 at opposite ends of one of the diagonals of the room, as described above. The effector 315 is connected according to an arrangement described in FIG. at the two linear elements 31 1, 312, the effector 31 6 is connected with the linear elements 313, 314. The orifices of the four linear elements allow the emission of interference signals Ji, J ₂ , J ₃ , J ₄ , the mobile phone 4 located in the room can decode the signals emitted by outsiders. The scrambling parameters, the power level, will be selected in particular according to the square arrangement of these linear elements.

FIG. 4 represents another embodiment, it will be possible to connect a first effector 42a at a first end 41a of the linear aerial 41 via a first connector 43a and a second effector 42b at the second end 41b of the linear overhead 41 via a second connector 43b in order to inject a jamming signal Ji, J ₂ , at each end of the linear overhead 41. In this case, the first and second effector have substantially identical characteristics (same emission levels, same frequency bands), but their signals are decorrelated according to a technique known to those skilled in the art in order to avoid the phenomena of interference and standing waves during their propagation in linear overhead.

 This embodiment allows in particular:

- to better homogenize the level of the interference signal J in linear aerials by means of two-way propagation, and to guarantee a better coverage of the interference,

 - to reduce the emission levels of the jamming signal at the ends of the overhead line and thus to ensure better jamming confinement.

 Without departing from the scope of the invention, other variants of implementation of the invention are possible.

For example, it is possible to add baffles to the device to locally optimize the confinement. For the nature, shape and size of the baffles, it is possible to use: grilles for the passage of electric cables (frequencies> 900 MHz) with inverted mounting, meshes and various geometries. The example of a rectangle grid opening grid. >

(λ / 2) ² (λ: wavelength of the interference emission) leads to a directivity of approximately 120 °, a forward / backward ratio of the order of 10 to 15 dB).

This facilitates the jamming of the jamming signal when installed in "semi-open environment", for example for windows prisons or window examination / conference rooms, or when there are diffraction problems

(metal pipes, other).

 Another variant is to add a metrology in phase installation / maintenance which facilitates the installation and adjustment of the device. For this purpose, it is possible to use a spectrum analyzer, or else mobile spectrum control stations known to those skilled in the art.

 According to another variant embodiment, it is possible to add a

"Over-network" of wired communications totally controlled, or a

"Over-network" of communications using line currents etc.

 According to another variant embodiment, it is possible to add a

Completely responsive "à la carte" on-line radiocommunication, by means of the following elements:

 • Choice of carrier frequencies based on a preliminary survey of the frequency schedules of the external networks according to methods known to those skilled in the art.

 • if necessary, frequency excision of the jamming signal to "release" the carriers and make them exploitable.

 • Installation of a local area network microphone using the released carriers and relays to external network.

Examples of components usable on the carriers released for such an on-network are wireless access points DECT (Digital Enhanced Cordless Telephone), pico / femto-cells of the third generation system UMTS (Universal Mobile Telecommunications System) or of the LTE (Long Term Evolution) standard, Wi-Fi or WiFi Direct points, UMTS "device-to-device" terminals or LTE manet (Release 12) terminals known to those skilled in the art, etc. The device and the method according to the invention notably have the following advantages:

 • total eradication of radiocommunications in the range 0.3 - 3 GHZ, with a single device according to the invention,

 • containment of the interference to a given area without impact on the external environment, because of the linear nature of the aerial and the consequent loss of cylindrical losses according to the formulation (1),

 • flexibility of installation, with a deployment of "à la carte" devices,

 • a maintenance facility,

 • many possibilities of extension in terms of added functions and in terms of services.

Claims

1 - Confined jamming device placed in a coverage zone in which prohibited radiocommunication devices may be located, the operation of which is sought to be prevented, characterized in that it comprises at least the following elements:

• at least one linear aerial (1) comprising several orifices Oi allowing the radiation of jamming signals, the linear aerial (1) being connected to one or more effectors (2) via a connector (3),

• said effector element(s) (2), being adapted to inject at at least one end of the linear aerial (1) one or more jamming signals, the power flow Ρ of the jamming signal J _jif in band B _jf of a carrier f is chosen such that the ratio Ps, _j /Pj,f, between the power flow Ps _j .t of the signal S _j ,f potentially usable by the prohibited device on the carrier f and the power flow Pj ,f, of the signal J _f present on the carrier f to prevent the prohibited device from operating is lower than the operating threshold Threshold _Sj ,f of the prohibited device (Psj/Pj,f≤ Thresholdsj.t), and in that

• the effector (2) is adapted to generate, for a point M(r,l) where a prohibited radiocommunication device (4) is located, a value of the spectral density Ν (Γ,Ι) of the jamming signal injected into the linear air via the connector (3) such that for band B,,f of each carrier f we have

10.logio(N _j , _f (r,l).B|, _f ) > 10.log ₁₀ (Ps _j ,f)-10.log ₁₀ (Thresholds _j , _f )+C(r ₀ )+P' .(l- lo)+10.log ₀ (r/r ₀ )+ where

. r, I, are the coordinates of a point M,

. I ₀ designates a linear reference distance, r ₀ designates a radial reference distance to the linear element,

. P' designates the rate of linear losses along the air radiating from the distance l ₀ ,

. -C(ro) designates the coupling losses in the band Bj at the reference radial distance r _0,

. η represents a precautionary margin taking into account additional attenuations of the jamming signal during its propagation from the air to the prohibited terminal.

2 - Jamming device according to claim 1 characterized in that said effector (2) is adapted to generate a transmission power taking into account one or more of the following elements:

- measurements of the levels of beacon, control and traffic signals coming from transmitters (8, 9, 10, 1 1) present in external networks and likely to enter into communication with illicit devices,

- the rate P' of linear losses in linear air,

- the losses by couplings -C(r ₀ ) of the linear aerial,

- margins η intended to compensate for additional attenuations of various nature which may affect the jamming signal J during its propagation from the linear aerial (1) to the device (4) to be jammed.

3 - Jamming device according to claim 1 in which the characteristics of the prohibited radiocommunication devices and the characteristics of the air radiation regime are previously known or measured to parameterize and adjust the frequency bands of the jamming signal, the nature of the jamming signals emitted and the output levels of the effector whose signal is injected into the air via the coupler (3).

4 - Jamming device according to one of the preceding claims characterized in that at least one of the effectors (2) is adapted to the generation and transmission of jamming signals and is a generic broadband jammer.

5 - Jamming device according to one of the preceding claims characterized in that the effector (2) adapted to the generation and transmission of jamming signals and is composed of a set of dedicated jammers, including the output signals are transmitted to filtering and amplification and rectification modules (6, 6'), then injected into a coupler (7), the output of said coupler (7) being injected into the linear aerial (1).

6 - Jamming device according to one of the preceding claims characterized in that the effector (2) adapted to the generation and transmission of jamming signals and comprises frequency-selective filtering modules adapted to excise the jamming signal to release one or more carriers usable by a controlled radio communications supernetwork.

7 - Jamming device according to one of the preceding claims characterized in that it comprises a means adapted to duplex the signal at the output of an effector and a device for injecting said signal into two different linear aerials.

8 - Jamming device according to one of the preceding claims characterized in that it comprises a first effector (42a) disposed at a first end (41 a) of the linear aerial (41) and a second effector (42b) disposed at a second end (41 b) of the linear aerial in order to inject a jamming signal Ji, J ₂ , at each end of the linear aerial (41).

9 - Jamming device according to one of the preceding claims characterized in that it comprises a system of baffles adapted to locally optimize confinement, such as grids for passing electrical cables with inverted mounting, mesh and geometric grills various. 10 - Method of confined jamming of the operation of one or more radiocommunication devices prohibited in a given area, implemented in the device according to one of claims 1 to 9 characterized in that it comprises at least the following steps :

• use at least one linear aerial (1) comprising several orifices Oi allowing the radiation of jamming signals, the linear aerial being connected to one or more effectors (2) via a connector (3),

· inject at at least one end of the linear aerial (1) one or more jamming signals, the power flow Ρ of the jamming signal J _jif in the band B _jf of a carrier f being chosen such that the ratio Ps /Pj,f, between the power flow P _S j,f of the signal Sj, _f potentially usable by the prohibited device on the carrier f and the power flow Pj,f, of the signal Jf present on the carrier f to prevent the device prohibited from operating is lower than the operating threshold Thresholdsj.t of the prohibited device (Ps /Pj,f≤ Thresholdsj.t).

1 1 - Confined jamming method according to claim 10 characterized in that a value of the spectral density N _jf (r,l) is generated for the jamming signal injected into the linear air such as for the band B _if of each carrier f:

10.logio(N],f(r,l).Bi,f) > 10.logi ₀ (Psj,f)-10.logio(Threshold _s ,j,f)+C(r ₀ )+P'. (L-

. r, I, are the coordinates of a point M,

. I ₀ designates a linear reference distance,

. r ₀ designates a radial reference distance to the linear element,

. P' designates the rate of linear losses along the air radiating from the distance l ₀ ,

. -C(r ₀ ) designates the coupling losses in the band Bj at the reference radial distance r _0,

_. η represents a precautionary margin taking into account additional attenuations of the jamming signal during its propagation from the air to the prohibited terminal.