JP7109060B2 - Electromagnetic wave suppression device and electromagnetic wave suppression method - Google Patents

Description

The present invention relates to a technology for suppressing electromagnetic waves emitted from mobile terminals such as mobile phones.

Until now, as shown in Patent Documents 1 to 3 below, in order to prevent radio waves emitted from mobile phones from affecting performances held at facilities and people using cardiac pacemakers, etc., Various devices and systems have been devised.

Japanese Patent Application Laid-Open No. 2003-08490 JP-A-11-88300 JP-A-2002-84226

However, since the above devices and systems use strong jamming waves to interfere with the operation of the mobile phone, there is a problem that medical equipment, measuring instruments, etc. may malfunction or stop the entire equipment. .

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and it is an object of the present invention to provide an apparatus and a method for preventing adverse effects such as malfunctions from occurring on devices and systems located around a mobile terminal. .

In order to solve the above problems, the present invention provides an electromagnetic wave suppressing device for suppressing electromagnetic waves emitted from a mobile terminal, comprising shielding means for electromagnetically shielding a closed space containing the mobile terminal from the outside of the closed space. and a pseudo base station that is provided in the closed space and communicates with a mobile terminal included in the closed space, but does not communicate with an object outside the closed space. .

Further, in order to solve the above problems, the present invention provides an electromagnetic wave suppression method for suppressing electromagnetic waves emitted from a mobile terminal, comprising a step of electromagnetically shielding a closed space containing the mobile terminal from the outside of the closed space. and providing, in the closed space, a pseudo base station that communicates with a mobile terminal included in the closed space but does not communicate with an object outside the closed space. do.

Advantageous Effects of Invention According to the present invention, it is possible to obtain a device and method for preventing adverse effects such as malfunctions from occurring on devices and systems located around a mobile terminal.

Fig. 1(a) is a graph showing the intensity (actual measurement) of radio waves emitted from a mobile phone. 1(b) shows a reception state in which three antennas are displayed on the monitor of the mobile phone, and FIG. 1(c) shows a reception state in which one antenna is displayed on the monitor of the mobile phone. Shows the radio wave intensity actually measured in a certain case. 1 is a block diagram showing the configuration of an electromagnetic wave suppressing device 1 according to an embodiment of the present invention; FIG. It is a flow chart which shows the electromagnetic wave suppression method concerning an embodiment of the invention. FIG. 3 is a diagram for explaining the intensity of radio waves emitted by the pseudo base station 3 shown in FIG. 2; 3 is a diagram for explaining the operation of the pseudo base station 3 shown in FIG. 2; FIG.

Embodiments of the present invention will be described in detail below with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts.

First, the communication operation by the mobile phone will be explained. 1A and 1B are graphs showing the intensity (measured values) of radio waves emitted from a mobile phone. 1(b) shows three antennas displayed on the monitor of the mobile phone. In FIG. 1(c), the monitor of the mobile phone shows one antenna. indicates the radio wave strength actually measured when the receiver is in a stable reception state.

It is known that mobile phones adjust the strength (power) of the radio waves they output according to the strength of the radio waves they receive. Specifically, the transmission power of a mobile phone increases the farther it is from the base station, and the radio wave is the strongest in the state immediately before the so-called "out of range" state (hereinafter referred to as "out of range mode") where no radio wave reaches. to send.

In the out-of-range-immediate mode, the mobile phone tries to notify the base station of its existence while emitting such strong radio waves, so the power consumption increases and the built-in battery drains quickly.

On the other hand, when the mobile phone is placed in a closed space such as a room that is completely electromagnetically shielded from the outside, the mobile phone goes into a so-called out-of-range mode, but as shown in FIG. 1(a). , it cannot communicate with a base station outside the closed space, so it does not emit radio waves. In the out-of-range mode, the mobile phone increases the reception sensitivity and repeatedly searches for radio waves emitted from the base station.

However, when looking at a general shielded room, there are openings and closings in the room, windows and ventilation holes in the room, and information lines and power lines that connect to the outside of the room. , unexpectedly, there are many cases where complete shielding is not realized. Further, in buildings such as reinforced concrete, there are often places where it is difficult for radio waves transmitted from a base station to arrive.

Therefore, when the mobile phone is placed in these places, it erroneously recognizes that the base station is far away, so it transmits radio waves with a higher intensity than usual in an attempt to stabilize communication with the base station.

Here, comparing FIG. 1(b) and FIG. 1(c), the reception condition in which only one antenna is displayed is better than the reception condition in which three antennas are displayed on the monitor of the mobile phone. It can be seen that the radio wave intensity output from the mobile phone can be 100 times or more higher in the case of poor performance.

Therefore, in the vicinity of devices such as measuring instruments and medical devices installed in a shielded room in order to avoid strong electromagnetic waves, or near conductive lines connected to these devices, the electromagnetic wave from a mobile phone as shown in Fig. 1(c). A situation may occur in which strong radio waves such as those emitted by

At this time, the influence of the radio waves may cause malfunctions in the above measuring instruments and medical devices, and may even stop the entire system to which these devices are connected. Furthermore, in facilities where such devices are installed, there is usually the possibility that there will be multiple operators and visitors. There may not be only one.

Jamming has been used to prevent this from happening, but jamming is strong enough to overwrite signals emitted by base stations and prevent mobile devices from decoding them. Since it is an electromagnetic wave, it is not suitable for use in environments where such strong electromagnetic waves should be avoided. Therefore, the electromagnetic wave suppressing device and the electromagnetic wave suppressing method according to the embodiments of the present invention described below are useful.

FIG. 2 is a block diagram showing the configuration of the electromagnetic wave suppressing device 1 according to the embodiment of the present invention. As shown in FIG. 2, the electromagnetic wave suppressing device 1 is an electromagnetic wave suppressing device for suppressing electromagnetic waves emitted from a mobile terminal such as a mobile phone. A shielding part 2 that electromagnetically shields, a pseudo base station 3 that is provided in the closed space and communicates with the mobile terminal PT but does not communicate with an external object, and the shielding part 2. An insulating structure, such as a reinforced plastic bar 4, which surrounds the outside and isolates the pseudo base station 3 from the shielding part 2, electrically insulates the closed space from the outside, and grounds the pseudo base station 3 and the shielding part 2. A noise filter (NF) provided in the middle of the ground line 6 connecting the pseudo base station 3 and the shielding part 2 to the ground line 6 and removing noise entering the closed space through the ground line 6 from the outside of the closed space. 8.

The reinforced plastic bars 4 and the noise filter 8 reliably cut the conduction noise (signal) that enters through the shielding part 2 and the ground wire 6 due to nearby base stations and electromagnetic field generators outside the building. prepared for. As a result, for example, a malicious person intentionally sends conduction noise from the outside as base station information. It is possible to avoid a situation in which the message is transmitted.

FIG. 3 is a flow chart showing an electromagnetic wave suppression method according to an embodiment of the present invention. As shown in FIG. 3, in the electromagnetic wave suppression method according to the embodiment of the present invention, in step S1, a closed space including a mobile terminal PT such as a mobile phone is electromagnetically shielded from the outside of the closed space.

Here, specifically, for example, as shown in FIG. 2, a shielding part 2 is provided so as to surround a building or room such as a laboratory or a hospital in which the measuring instruments and medical equipment are installed.

Next, in step S2, the pseudo base station 3, which communicates with the portable terminal PT included in the closed space but does not communicate with objects outside the closed space, is provided in the closed space. Specifically, for example, the pseudo base station 3 is installed in the above building or room.

Since the pseudo base station 3 can make the mobile terminal PT recognize that the base station is sufficiently close, the mobile terminal PT transmits radio waves with high intensity to search for the base station as described above. no longer needed. As a result, the intensity of radio waves transmitted from the mobile terminal PT can be minimized.

FIG. 4 is a diagram for explaining the intensity of radio waves emitted by the pseudo base station 3 shown in FIG. As shown in FIG. 4, the radio wave intensity (radio wave level) L2, which makes the mobile terminal PT recognize that the base station is located near the mobile terminal PT, is higher than the radio wave level L1 that barely reaches the mobile terminal PT from the base station. At this time, the radio wave level of the jamming is assumed to be strong within the range R2, which is larger than the radio wave level L2, but the strength of the radio wave transmitted by the pseudo base station 3 is within the range R1 between the radio wave level L1 and the radio wave level L2. It is considered to be weaker than the electromagnetic resistance of the above-mentioned measuring instruments and medical equipment.

In addition, the pseudo base station 3 responds to various requests from the mobile terminal PT in a pseudo manner as if a regular base station were nearby. It continues to control the mobile terminal PT so that it does not grow.

However, when the pseudo base station 3 receives the call information from the mobile terminal PT, it returns to the mobile terminal PT a notification indicating that it cannot communicate with an object outside the indoor. In this reply, since the pseudo base station 3 is located near the mobile terminal PT, a weak radio wave is used.

On the other hand, when the mobile terminal PT does not make a call, the mobile terminal PT continues to receive the signal from the pseudo base station 3 while the power consumption is suppressed. The radio wave transmitted from the base station outside the shielding part 2 does not reach the mobile terminal PT due to the shielding effect of the shielding part 2, so that the mobile terminal PT is not called.

By the way, in general, all wireless base stations transmit regional signals representing their regions, and mobile phones constantly receive these regional signals. Then, when the mobile phone detects that it has moved to the new area by receiving an area signal indicating a new area, it sends the area before and after the movement to the home memory station 7 via the exchange 5 shown in FIG. report.

Therefore, as shown in FIG. 5, the mobile terminal PT inside the shielding unit 2 shown in FIG. An attempt is made to report this notification to the home memory station 7 via the simulated base station 3 and switching center 5, but the simulated base station 3 discards this notification. Therefore, in the electromagnetic wave suppressing device 1 according to the embodiment of the present invention, communication between the pseudo base station 3 and the switching center 5 is not performed as shown in FIG.

As a result, since the pseudo base station 3 does not communicate with the exchange 5, the power consumption is significantly reduced compared to a general radio base station, and the pseudo base station 3 can also be used in the mobile terminal PT. is located nearby, the strength of the radio wave used for making the above report to the pseudo base station 3 can be weak.

As described above, according to the electromagnetic wave suppressing device and the electromagnetic wave suppressing method according to the embodiment of the present invention, a mobile terminal PT such as a mobile phone is brought into a laboratory, an operating room of a hospital, a control room of a nuclear power plant, etc., for example. Even if the mobile terminal PT is exposed to the environment, the intensity of the electromagnetic waves output by the mobile terminal PT can be suppressed, so that the devices and systems placed in the above-mentioned laboratory can be prevented from malfunctioning and other adverse effects. An electromagnetic environment can be constructed.

Further, according to the electromagnetic wave suppressing device and the electromagnetic wave suppressing method according to the embodiment of the present invention, since the mobile terminal PT searches for the closest base station, it is not necessary to increase the reception sensitivity. Power consumption can also be reduced.

In the above, although imperfect, spaces with electromagnetic shielding means, such as sites isolated from the outside in buildings with steel structures and spaces surrounded by conductors such as airplanes, It should be noted that there is no need to construct a new shielding means for shielding the area, and it can be used as it is.

1 Electromagnetic wave suppression device 2 Shielding part 3 Pseudo base station 4 Reinforced plastic muscle 6 Ground wire 8 Noise filter (NF)

Claims (7)

An electromagnetic wave suppression device for suppressing electromagnetic waves emitted from a mobile terminal,
a shielding means for electromagnetically shielding a closed space containing the mobile terminal from the outside of the closed space;
Provided in the closed space, communication is performed at an intensity between a first radio wave level that barely reaches the mobile terminal contained in the closed space and a second radio wave level that causes the mobile terminal to recognize that the mobile terminal is in a close position. and a pseudo base station that does not communicate with the external object. 2. The electromagnetic wave suppressing device according to claim 1, wherein, when receiving call information from said mobile terminal, said pseudo base station returns to said mobile terminal a notification indicating that communication with said external object is impossible. . 2. The electromagnetic wave suppressing device according to claim 1, wherein, when receiving from the portable terminal a notification indicating that the pseudo base station has been selected as a new base station to communicate with, the pseudo base station discards the notification. An electromagnetic wave suppression device for suppressing electromagnetic waves emitted from a mobile terminal,
a shielding means for electromagnetically shielding a closed space containing the mobile terminal from the outside of the closed space;
a pseudo base station that is provided in the closed space and communicates with the mobile terminal included in the closed space but does not communicate with objects outside the closed space;
insulating means provided to surround the shielding means and electrically insulating the closed space from the outside;
grounding means for grounding the pseudo base station and the shielding means;
An electromagnetic wave suppressing device comprising noise removing means for removing noise entering said closed space through said grounding means. An electromagnetic wave suppression method for suppressing electromagnetic waves emitted from a mobile terminal,
a step of electromagnetically shielding a closed space containing the mobile terminal from the outside of the closed space;
While communicating with the mobile terminal contained in the closed space at an intensity between a first radio wave level that barely reaches the mobile terminal and a second radio wave level that makes the mobile terminal recognize that it is in a position close to the mobile terminal, the mobile terminal is located outside the closed space. and providing a pseudo base station, which does not communicate with objects, in the closed space. 6. The pseudo base station according to claim 5, wherein, when receiving call information from said mobile terminal, said pseudo base station returns to said mobile terminal a notification indicating that communication with said external object is impossible. Electromagnetic wave suppression method. 6. The electromagnetic wave suppression according to claim 5, wherein, when receiving from the mobile terminal a notification indicating that the pseudo base station has been selected as a new base station to communicate with, the pseudo base station discards the notification. Method.

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