CN108737015B - Method and system for shielding GSM mobile phone signals - Google Patents
Method and system for shielding GSM mobile phone signals Download PDFInfo
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- 230000005540 biological transmission Effects 0.000 claims description 26
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- NMFHJNAPXOMSRX-PUPDPRJKSA-N [(1r)-3-(3,4-dimethoxyphenyl)-1-[3-(2-morpholin-4-ylethoxy)phenyl]propyl] (2s)-1-[(2s)-2-(3,4,5-trimethoxyphenyl)butanoyl]piperidine-2-carboxylate Chemical compound C([C@@H](OC(=O)[C@@H]1CCCCN1C(=O)[C@@H](CC)C=1C=C(OC)C(OC)=C(OC)C=1)C=1C=C(OCCN2CCOCC2)C=CC=1)CC1=CC=C(OC)C(OC)=C1 NMFHJNAPXOMSRX-PUPDPRJKSA-N 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
- H04K3/00—Jamming of communication; Counter-measures
- H04K3/60—Jamming involving special techniques
- H04K3/62—Jamming involving special techniques by exposing communication, processing or storing systems to electromagnetic wave radiation, e.g. causing disturbance, disruption or damage of electronic circuits, or causing external injection of faults in the information
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention discloses a shielding method and a system for GSM mobile phone signals, which adopt interference mobile phone uplink frequency to realize shielding. Detecting and identifying whether the uplink signal strength reaches a set level threshold in the uplink time slot period by utilizing the characteristic that at least one uplink time slot period exists in the uplink signal transmitted by the mobile phone, and judging whether the transmitting mobile phone is positioned in a shielding area according to the detected uplink signal strength; and for the mobile phone which is judged to be positioned in the shielding area, transmitting a shielding interference signal with the same time slot, so that the intensity of the interference signal is larger than the intensity of an uplink signal transmitted by the mobile phone to interfere the receiving of the base station, and thus, the communication of the mobile phone is interrupted. A GSM mobile phone signal shielding system comprises an uplink receiving antenna, a filter, a power detection comparator, an interference transmitter and an uplink interference antenna. By adopting the method and the system provided by the invention, other users in the area can not be influenced when the GSM mobile phone signal is shielded, and the mobile phone is not transmitted when not used, so that the waste is reduced, and the wireless signal pollution is reduced.
Description
Technical Field
The invention relates to the field of shielding of mobile communication, in particular to a method and a system for shielding GSM mobile phone signals.
Background
For shielding of GSM mobile phones, interference downlink frequency is mostly adopted to realize shielding, and there are common frequency sweep type shielding devices, white noise interference type shielding devices, frequency sweep type shielding devices or combined fixed frequency type shielding devices formed by combining white noise interference type shielding devices and fixed frequency type shielding devices, wherein when aiming at strong base station signals, a plurality of frequency points are selected for strengthening interference at a plurality of base stations with strongest vicinity, namely N-point frequency type interference. Taking the same frequency band signal as an example, there are two operators ' base stations, for example, one operator's base station is close to the other operator's base station and the signal is strong, and the other operator's base station is far away from the other operator's base station and the signal is weak, then the strength of the shielding is set according to the base station with the strongest signal, and for the base station with the weak signal, because the shielding is set according to the base station with the strongest signal, the shielding is too strong for the base station with the weak signal, that is, the shielding area is large, so that the shielding area covered by the operator with the weak signal exceeds the requirement, and the communication of users exceeding the requirement of the shielding area is difficult, thereby causing user complaints and the like.
The patent of publication number CN103607254B discloses a self-interference type shielding device which is applicable to various system mobile phone signals including GSM system, and adopts the following technology: the local receiving and transmitting antenna receives and stores the downlink air signal, and transmits the signal according to a certain rule and makes it larger than the original signal so as to realize effective shielding. However, this technique has the following problems: in view of the characteristics of GSM, the BCCH carrier is continuously transmitted, and the TCH carrier is transmitted as required, so the shielding of the BCCH carrier by the technology of this patent is complete, but because the TCH carrier receiving time slot has randomness, it cannot be guaranteed that the TCH carrier can be taken to the user transmitting time slot, i.e. the shielding is normal when the TCH carrier is received and is not transmitted when the TCH carrier is received, and the shielding is lost because the TCH carrier is not transmitted so that the shielding of the TCH carrier is not effective.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and realize shielding of GSM mobile phone signals by interfering uplink signals of the GSM mobile phone, and clean shielding areas can be realized without influencing other users due to no downlink signal interference; in addition, the mobile phone does not emit when not used, so that the waste is reduced, and the wireless signal pollution is reduced.
The aim of the invention is achieved by the following technical scheme. A method for shielding GSM handset signals, the method comprising the steps of:
(1) Monitoring all uplink frequencies in the shielding area, and capturing uplink signals of the GSM mobile phone;
(2) Detecting and identifying whether the uplink signal strength reaches a set power level threshold in the uplink time slot period by utilizing the characteristic that at least one uplink time slot period exists in the uplink signal transmitted by the mobile phone, and judging whether the transmitting mobile phone is positioned in a shielding area according to the characteristic;
(3) And for the mobile phone which is judged to be positioned in the shielding area, transmitting a shielding interference signal with the same time slot, so that the intensity of the interference signal is larger than the intensity of an uplink signal transmitted by the mobile phone to interfere the receiving of the base station, and thus, the communication of the mobile phone is interrupted.
In the prior art, the downlink frequency of the interference GSM mobile phone is mostly adopted to realize shielding, and the subversion of the invention adopts the uplink frequency of the interference GSM mobile phone to realize the shielding. Because the interference is aimed at a single mobile phone, the shielding interference of the same time slot is transmitted only when the GSM mobile phone transmission is detected in the shielding area. By utilizing the characteristic that the uplink signal transmitted by the mobile phone has at least one uplink time slot period, because the power of the GSM uplink time slot is basically constant in the whole time slot length, the power of the part of time in front of the time slot can be considered as the power level of the time slot, and whether the mobile phone is positioned in a shielding area or not can be judged according to the power level, and for the mobile phone judged to be positioned in the shielding area, the same time slot interference is transmitted in the rest time of the time slot length so as to achieve the purpose of interfering the base station reception, thereby realizing the purpose of shielding the mobile phone. Because the GSM base station allocates independent uplink time slots for each mobile phone user, the interference implemented in the uplink time slot period of the invention does not influence the normal communication of other mobile phone users for the GSM base station. The invention realizes no useless emission, effectively reduces energy waste and pollution.
It should be further noted that, in the conventional shielding technology, the GSM mobile phone is shielded by shielding the downlink signal, and for the case that the base station adopts the radio frequency hopping technology, all TCH carriers need to be shielded at the same time to participate in the frequency hopping frequency points, and the number of frequency points of the TCH carriers participating in the frequency hopping is large, generally more than 10, so that great power needs to be consumed. The technology provided by the invention is not affected by the method, and because the technology monitors all uplink signals in the whole shielding area, the system can capture whether the base station adopts a radio frequency hopping technology or not. For the use of radio frequency hopping, the present technique is only related to the number of real-time slots at the time of transmission of the mobile phone user in the shielded area, for example: if two time slots transmit in the same time, only the frequency points corresponding to the two time slots are transmitted, and the next time slot can track the other two frequency points corresponding to the respective frequency hopping sequences in real time according to the detection of the transmitting signals of the mobile phone, but the required transmitting frequency points are two, namely two real-time TCH carriers, so that great power consumption is not required, and the energy waste and the communication interference to normal users are reduced.
The invention can be further defined and perfected by the following technical scheme:
as a technical scheme, before transmitting the shielded interference signals in the same time slot, the uplink signals transmitted by the mobile phone and other shielded interference signals in the shielded area are also required to be screened; further detecting and identifying whether the uplink signal strength reaches a set power level threshold for the mobile phone signal; the next operation is suspended for the other signals determined to be the shielding interference signals. For the case of a larger shielding range, a plurality of shielding devices are generally required to be arranged in a shielding area so that the whole area has a better shielding effect, and therefore, uplink signals transmitted by mobile phones in the shielding area are required to be screened from interference signals transmitted by other shielding devices in the shielding area. Further transmitting a shielding interference signal of the same time slot for the mobile phone signal; and stopping the next shielding emission for the other shielding interference signals.
As a technical scheme, the uplink time slot period transmitted by the mobile phone includes an identification detection period and a shielding transmission period; the identifying and detecting period is used for detecting and identifying whether the strength of the uplink signal reaches a set power level threshold, transmitting a shielding interference signal of the same time slot in the shielding transmitting period when the strength of the uplink signal exceeds the set power level threshold, and enabling the strength of the interference signal to be larger than the strength of the uplink signal transmitted by the mobile phone so as to interfere the receiving of the base station, thereby interrupting the communication of the mobile phone. For the occasion that the shielding area is smaller, a single shielding can cover the whole shielding area, namely, only a single shielding emission signal exists in the whole shielding area, so that whether other shielding equipment emits shielding emission signals or not is not needed to be judged, and whether the shielding equipment is located in the shielding area or not is judged only by the uplink signal intensity emitted by a mobile phone and the shielding is realized.
When other shielding interference signals exist in the shielding area, the identification detection period is also used for screening uplink signals transmitted by the mobile phone from other shielding interference signals in the shielding area, detecting whether the uplink signal strength reaches a set power level threshold or not further, transmitting the shielding interference signals in the same time slot in the shielding transmission period when the uplink signal strength exceeds the set level threshold, and enabling the strength of the interference signals to be larger than that of the uplink signals transmitted by the mobile phone so as to interfere the receiving of the base station, thereby interrupting the communication of the mobile phone.
As one technical solution, in the shielded area, the transmission frequencies of the physically adjacent shielded interference signals are different. For a plurality of shields that transmit co-frequency interference signals to work together to enlarge the shielded area, there may be the following problems: the shielding devices detect the transmission of the same mobile phone at the same time to transmit shielding interference signals, and the same-frequency signals possibly become similar in power and opposite in phase due to time difference when reaching the receiving antenna, and are overlapped and offset, so that shielding failure is caused by insufficient strength of shielding transmission signals received by the base station. Therefore, when the shielding device is arranged, the frequency of signals transmitted by the shielding device is different from that of nearby devices, namely the transmitted interference signals are grouped, the transmission frequencies of the respective interference signals are different, and the physical adjacencies refer to adjacent installation positions, so that the problem that the adjacent shielding devices detect the same mobile phone at the same time and the opposite phase superposition of the same-frequency interference signals at a receiver is offset is avoided; the same way can also prevent the problem that the shielding emission detection and the receiving of the shielding device are counteracted because of the reverse superposition caused by the same frequency.
As a technical scheme, an uplink time slot training method is adopted: before the interference signal of the same time slot is transmitted, the uplink time slot boundary of the uplink carrier of the mobile phone and the time slot length are obtained, wherein the time slot boundary comprises a time slot starting boundary and a time slot ending boundary, and the uplink time slot boundary and the time slot length form an uplink time slot period. In order to accurately obtain the time slot boundary, an uplink time slot training method can be adopted to obtain the time slot boundary of the uplink carrier of the mobile phone and the duration of the time slot, wherein the time slot boundary comprises a time slot starting boundary and a time slot ending boundary. Specifically, when only one mobile phone needing shielding is in the shielding area, the shielding is not started, only the uplink signal is received, after one or more time slot signals are completely received, the uplink time slot boundary of the carrier is obtained, namely the training base station 1 is obtained, then after the mobile phone transmits the uplink signal again, the mobile phone is synchronously aligned with the time slot training base station 1 through the time slot starting boundary, the time slot power level judgment is started, and the shielding is started to implement interference after the power level is reached. The initial boundary of the training base station 1 of the non-aligned time slot is abandoned, and for the situation that a plurality of mobile phones to be shielded may exist in the shielding area, as the mobile phones may be respectively connected to different base stations, the boundary of the uplink time slots of the mobile phones may not be completely aligned, i.e. a certain offset exists, and the method can be seen in fig. 1 specifically; for the situation that the time slot boundaries are not aligned, another uplink time slot training is required to be started to obtain the time slot boundary (such as the training base station 2) of another base station, the method is the same as above, and the shielding emission of the next step is carried out after the initial boundary is aligned by synchronization, so that random radio frequency interference of uplink frequencies transmitted by some non-mobile phones can be filtered (because only the radio frequency signals of the time slot initial boundary of which the training (the base stations 1 to M) are already obtained can enter the shielding judgment starting program), the influence of shielding emission transmitted by corresponding erroneous judgment caused by the random radio frequency interference of the uplink frequencies transmitted by the non-mobile phones is reduced, and the interference to the base station is reduced.
Preferably, in the uplink time slot training method, the mobile phones corresponding to each base station are shielded in order, based on the time slot training base station 1, the time slot cycle period of the time slot training base station is utilized to shield the mobile phones under one base station, then the time slot training period of the mobile phone corresponding to the other base station is found, and all the mobile phones under all the different base stations in the shielding area are shielded in order repeatedly. It should be noted that, when the transmitting interference is shielded in general, unless the transmitting antenna is far away from the shielding device, the uplink receiving circuit of the mobile phone in the same frequency band has larger blocking interference; therefore, when the interference of the emission is shielded, the receiving of the uplink signal of the mobile phone is simultaneously considered to be closed, thereby causing the time discontinuity of a receiving circuit and adversely affecting the receiving process, such as the reading of an uplink time slot boundary during the shielding of the interference of the emission; the uplink signals transmitted between all mobile phones under one base station are time slot aligned, namely, the shielding transmission is closed and then the next time slot is started; therefore, the invention can not miss to shield all mobile phones in the shielding range of the shielding device under the same base station. Based on the time slot training base station 1, the invention firstly shields the mobile phones under the base station by using the time slot cycle period of the time slot training base station, namely, after shielding for a period of time, all the mobile phones are off-line, and then verifies whether the mobile phones in the shielding area are off-line or not by receiving for a period of time, namely, the mobile phones which are not aligned with the time slot training period of the base station transmit uplink signals; then find the time slot training period of the corresponding mobile phone of another base station, so the repetition can shield all mobile phones in the shielding device area under all different base stations in order.
Preferably, the center frequency of the transmitted interference signal of the same time slot is offset by a certain amount from the center frequency of the carrier signal of the GSM handset. For example, the center frequency of the transmitted co-slotted interfering signal is +60kHz, or +67kHz, or still +74kHz, or still-60 kHz, or still-67 kHz, or still-74 kHz, of the center frequency of the GSM handset carrier signal.
Preferably, the uplink signal of the GSM handset can be obtained by a diversity reception technique that adds diversity reception antennas and diversity reception circuitry. The adoption of diversity technology can effectively reduce poor reception caused by the fast fading effect of the GSM uplink signal, so as to increase the stability of reception.
The invention also provides a shielding system of the GSM mobile phone signal corresponding to the method, which mainly comprises an uplink receiving antenna, a filter, a power detection comparator, an interference transmitter and an uplink interference antenna; the uplink signal of the GSM mobile phone in the shielding area is captured by an uplink receiving antenna, filtered by a filter and then transmitted to a power detection comparator, and whether the uplink signal strength reaches a set power level threshold or not is detected and identified in an uplink time slot period, so that whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged; for a mobile phone determined to be located in the shielding area, the power detection comparator sends a signal to the interference transmitter to inform the interference transmitter of a simultaneous interference signal with the transmission intensity being greater than the uplink signal intensity transmitted by the mobile phone so as to shield the mobile phone.
As a technical scheme, the filter comprises a carrier wave filtering module, wherein the carrier wave filtering module is used for filtering uplink signals of the mobile phone; the signal in the shielding area is captured by an uplink receiving antenna, filtered by a carrier wave filtering module and then transmitted to a power detection comparator so as to judge whether the signal is a mobile phone signal, and for judging the mobile phone signal, whether the signal strength of the mobile phone signal reaches a set power level threshold or not is detected, and whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged; for a cell phone determined to be located in the shielded area, the power detection comparator sends a signal to the interference transmitter informing the interference transmitter to transmit the co-time slot interference signal to shield the cell phone.
As another technical scheme, the filter further comprises a shielding interference signal filtering module, wherein the shielding interference signal filtering module is used for filtering signals transmitted by other shielding devices in the shielding system; the signal in the shielding area is captured by the uplink receiving antenna, and then is respectively filtered by the carrier wave filtering module and the shielding interference signal filtering module and then is transmitted to the power detection comparator to judge whether the signal is a mobile phone signal, and for judging the mobile phone signal, whether the signal strength of the mobile phone signal reaches a set power level threshold or not is detected, and whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged; for a cell phone determined to be located in the shielded area, the power detection comparator sends a signal to the interference transmitter informing the interference transmitter to transmit the co-time slot interference signal to shield the cell phone.
In the two technical schemes, the power detection comparator can identify the difference between the mobile phone signal and the signal characteristics of other shielding devices in the shielding area, such as the difference characteristics of frequency spectrum, center frequency and the like; the screening can be detected by the characteristic of the difference of the output powers of the corresponding filters with different bandwidths and center frequencies, because the power of the shielding transmitting signals is in the corresponding shielding filter band which is set according to the characteristics of the shielding signals, when other shielding devices transmit shielding interference signals and no mobile phone transmits signals, the detected power of the carrier wave filter which is used as comparison is basically the same as the detected power after the shielding filters, and therefore, the power obtained by the shielding filters is regarded as the signal transmitted by the shielding devices if the power obtained by the shielding filters is basically the same; otherwise, if the power of the GSM signal transmitted by the mobile phone is uniformly distributed in the GSM carrier bandwidth, the shielding filter only has partial power because of the partial bandwidth of the GSM carrier filter, namely the power obtained by the GSM filter is much larger, the power is considered as the uplink signal of the mobile phone, and the transmitted signals of the shielding devices are screened out according to the difference so as to prevent the mutual lifting among the shielding devices from self-excitation.
As a technical scheme, the carrier wave filtering module and the interference signal shielding filtering module have different working center frequencies and different bandwidths. Preferably, the bandwidth of the carrier wave filtering module is 200kHz, and the bandwidth of the interference shielding signal filtering module is 20kHz.
Preferably, the center frequency of the interference signal transmitted by the uplink interference transmitter is offset by a certain amount from the center frequency of the carrier signal. The decision frequency of the corresponding receiving circuit is as close as possible to the modulation change corresponding to the symbol jump, so as to increase the disturbance of the anti-interference circuit for decoding the mobile phone and increase the shielding power efficiency. For example, the center frequency of the interference signal transmitted by the uplink interference transmitter is +60kHz, or +67kHz, or +74kHz, or-60 kHz, or-67 kHz, or-74 kHz, of the center frequency of the carrier signal.
In summary, the invention utilizes the characteristic that the uplink signal transmitted by the GSM mobile phone has at least one uplink time slot period, and transmits the interference signal of the same time slot as the uplink signal after identifying and judging that the mobile phone is positioned in the shielding area, so as to realize shielding of GSM mobile phone communication, and the interference implemented in the uplink time slot does not influence the normal communication of other users, thereby realizing no useless transmission, effectively reducing energy waste and pollution.
Drawings
Fig. 1 is a schematic diagram illustrating the difference between uplink transmission time slots of GSM handsets corresponding to different base stations;
fig. 2 is a schematic diagram of the slot mask principle of the present invention in embodiment 1.
Fig. 3 is a schematic diagram showing allocation of slot periods in embodiment 1;
fig. 4 is a schematic structural view of a shielding system according to the present invention in embodiment 2;
fig. 5 is a schematic structural view of another shielding system according to the present invention in embodiment 3;
FIG. 6 is a schematic logic diagram of the power detection comparator in embodiment 3;
fig. 7 is a schematic diagram of the operating bandwidths and the center frequencies of the carrier filter module and the shielding interference signal filter module when the shielding transmitting time slot interference signal is at the positive frequency in embodiment 3.
Detailed Description
Example 1
The invention will now be described in detail with reference to the accompanying drawings and examples: as shown in fig. 2, the invention discloses a shielding method of GSM mobile phone signals, which comprises the following steps:
(1) Monitoring all uplink frequencies in the shielding area, and capturing uplink signals of the GSM mobile phone;
(2) Detecting and identifying whether the uplink signal strength reaches a set power level threshold in the uplink time slot period by utilizing the characteristic that at least one uplink time slot period exists in the uplink signal transmitted by the mobile phone, and judging whether the transmitting mobile phone is positioned in a shielding area according to the characteristic;
(3) And for the mobile phone which is judged to be positioned in the shielding area, transmitting a shielding interference signal with the same time slot, so that the intensity of the interference signal is larger than the intensity of an uplink signal transmitted by the mobile phone to interfere the receiving of the base station, and thus, the communication of the mobile phone is interrupted.
In the prior art, the downlink frequency of the interference GSM mobile phone is mostly adopted to realize shielding, and the subversion of the invention adopts the uplink frequency of the interference GSM mobile phone to realize the shielding. Because the interference is aimed at a single mobile phone, the shielding interference of the same time slot is transmitted only when the GSM mobile phone transmission is detected in the shielding area. By utilizing the characteristic that the uplink signal transmitted by the mobile phone has at least one uplink time slot period, because the power of the GSM uplink time slot is basically constant in the whole time slot length, the power of the part of time in front of the time slot can be considered as the power level of the time slot, and whether the mobile phone is positioned in a shielding area or not can be judged according to the power level, and for the mobile phone positioned in the shielding area after the judgment, the same time slot interference is transmitted in the rest time of the time slot length so as to achieve the purpose of interfering the base station reception, thereby realizing the purpose of shielding the mobile phone. Because the GSM base station allocates independent uplink time slots for each mobile phone user, the interference implemented in the uplink time slot period of the invention does not influence the normal communication of other mobile phone users for the GSM base station. The invention realizes no useless emission, effectively reduces energy waste and pollution.
Before transmitting the interference signal of the same time slot, an uplink time slot training method is adopted to obtain the uplink time slot boundary and the time slot length of the uplink carrier of the mobile phone, wherein the time slot boundary comprises a time slot starting boundary and a time slot ending boundary, and the uplink time slot boundary and the time slot length form an uplink time slot period. Specifically, when only one mobile phone needing shielding is in the shielding area, the shielding is not started, only the uplink signal is received, after one or more time slot signals are completely received, the uplink time slot boundary of the carrier is obtained, the training base station 1 is obtained, and then when the mobile phone transmits the uplink signal again, the time slot level comparison is started after the alignment identification is correct, and then the interference is implemented. For the situation that a plurality of mobile phones to be shielded possibly exist in the shielding area, as the mobile phones possibly access different base stations respectively, the boundaries of uplink time slots of the mobile phones possibly cannot be completely aligned, namely certain offset exists; for the case that the time slot boundaries are not aligned, another uplink time slot training is required to be started to obtain the time slot boundary of another base station, the training base station 2 is obtained, and the next shielding emission is carried out after the time slot starting boundary is aligned and identified correctly through synchronization, and so on, the interference of the radio frequency interference of the non-aligned base station starting boundary to the shielding emission emitted by the corresponding misjudgment caused by the interference of the shielding mobile phone uplink time slot signal identification system can be filtered.
It should be noted that, when the transmitting interference is shielded in general, unless the transmitting antenna is far away from the shielding device, the uplink receiving circuit of the mobile phone in the same frequency band has larger blocking interference; therefore, when the interference of the emission is shielded, the receiving of the uplink signal of the mobile phone is simultaneously considered to be closed, thereby causing the time discontinuity of a receiving circuit and adversely affecting the receiving process, such as the reading of an uplink time slot boundary during the shielding of the interference of the emission; the uplink signals transmitted between all mobile phones under one base station are time slot aligned, namely, the shielding transmission is closed and then the next time slot is started; therefore, the invention can not miss to shield all mobile phones in the shielding range of the shielding device under the same base station. Based on the time slot training base station 1, the invention firstly shields the mobile phones under the base station by using the time slot cycle period of the time slot training base station, namely, after shielding for a period of time, all the mobile phones are off-line, and then verifies whether the mobile phones in the shielding area are off-line or not by receiving for a period of time, namely, the mobile phones which are not aligned with the time slot training period of the base station transmit uplink signals; then find the time slot training period of the corresponding mobile phone of another base station, so the repetition can shield all mobile phones in the shielding device area under all different base stations in order. As shown in fig. 3, the uplink time slot period transmitted by the mobile phone includes a detection discrimination period and a shielding transmission period, wherein the detection period is identified to detect whether the uplink signal strength reaches a set power level threshold; and transmitting a shielding interference signal with the same time slot in a shielding transmission period when the strength of the uplink signal exceeds a set power level threshold, and enabling the strength of the interference signal to be larger than that of the uplink signal transmitted by the mobile phone so as to interfere the receiving of the base station, thereby interrupting the communication of the mobile phone.
Example 2
As shown in fig. 4, this embodiment discloses a shielding system for GSM mobile phone signals, which mainly includes an uplink receiving antenna, a filter, a power detection comparator, an interference transmitter and an uplink interference antenna; the filter is a carrier filter module. The uplink signal of the GSM mobile phone in the shielding area is captured by an uplink receiving antenna, filtered by a filter and then transmitted to a power detection comparator so as to detect and identify whether the uplink signal strength reaches a set power level threshold in an uplink time slot period, and whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged; for a mobile phone determined to be located in the shielding area, the power detection comparator sends a signal to the interference transmitter to inform the interference transmitter of a simultaneous interference signal with the transmission intensity being greater than the uplink signal intensity transmitted by the mobile phone so as to shield the mobile phone.
Example 3
As shown in fig. 5, the inside of the oval shape in the drawing is a large-range shielding region in which, in addition to the present shielding system (the virtual frame portion), there are the shield 1, the shield 2, the shield 3, and the shield 4. Unlike embodiment 2, the filter in the shielding system includes a carrier wave filtering module and a shielding interference signal filtering module, where the carrier wave filtering module is used to filter the uplink signal of the mobile phone, and the shielding interference signal filtering module is used to filter the interference signals emitted by other shielding devices in the shielding area. The carrier wave filtering module and the interference signal shielding filtering module have different working center frequencies and different bandwidths.
For the case of larger shielding range, a plurality of shielding devices are generally required to be arranged in a shielding area so that the whole area has a better shielding effect, in order to avoid the mutual lifting of the plurality of shielding devices, shielding interference signals sent by other shielding devices are mistakenly used as uplink signals sent by a mobile phone, and screening is required to be carried out on the uplink signals sent by the mobile phone and shielding interference signals sent by other shielding devices before the same-frequency interference signals are sent. The method comprises the steps that signals in a shielding area are captured by an uplink receiving antenna, are respectively filtered by a carrier wave filtering module and a shielding interference signal module in a filter and then are transmitted to a power detection comparator, the power detection comparator firstly discriminates whether the signals are mobile phone signals or not in a recognition detection period, and for discriminating the signals to be mobile phone signals, whether the power level of an uplink time slot of the signals reaches a set threshold or not is detected, and whether a mobile phone transmitting the uplink signals is located in the shielding area or not is judged; for a mobile phone determined to be located in the shielding area, the power detection comparator sends a signal to the interference transmitter to inform the interference transmitter to transmit the co-time slot interference signal to shield the mobile phone, as shown in fig. 6.
For a plurality of shields that transmit co-frequency interference signals to work together to enlarge the shielded area, there may be the following problems: the shielding devices detect the transmission of the same mobile phone at the same time to transmit shielding interference signals, and the same-frequency signals possibly become similar in power and opposite in phase due to time difference when reaching the receiving antenna, and are overlapped and offset, so that shielding failure is caused by insufficient strength of shielding transmission signals received by the base station. Therefore, when the shielding device is arranged, the frequency of signals transmitted by the shielding device is different from that of nearby devices, namely the transmitted interference signals are grouped, the transmission frequencies of the respective interference signals are different, and the physical adjacencies refer to adjacent installation positions, so that the problem that the adjacent shielding devices detect the same mobile phone at the same time and the opposite phase superposition of the same-frequency interference signals at a receiver is offset is avoided; the same way can also prevent the problem that the shielding emission detection and the receiving of the shielding device are counteracted because of the reverse superposition caused by the same frequency.
As shown in fig. 7, the carrier filter module preferably has an operating bandwidth of 200kHz, and the interference signal shielding filter module preferably has an operating bandwidth of 20kHz. Preferably, the interference signal transmitted by the uplink interference transmitter is a center frequency offset of the carrier signal by a certain amount. The frequency of the interference signal transmitted by the interference transmitter is +60kHz, or +67kHz, or +74kHz, or-60 kHz, or-67 kHz, or-74 kH of carrier center frequency shift.
The uplink reception adopts a diversity reception technology, a diversity reception antenna and a diversity reception circuit are added, and the adoption of the diversity technology can effectively reduce poor reception caused by the fast fading effect of the GSM uplink signal so as to increase the stability of the reception.
It should be understood that equivalents and modifications to the technical scheme and the inventive concept of the present invention should fall within the scope of the claims appended hereto.
Claims (13)
1. A shielding method for GSM mobile phone signals in a shielding area is characterized in that: the method comprises the following steps:
(1) Monitoring all uplink frequencies in the shielding area, and capturing uplink signals of the GSM mobile phone;
(2) The method comprises the steps that the characteristic that an uplink signal transmitted by a GSM mobile phone has at least one uplink time slot period is utilized, the uplink time slot period comprises a recognition detection period and a shielding transmission period, whether the strength of the uplink signal reaches a set power level threshold or not is detected and recognized in the recognition detection period, and whether the transmitting GSM mobile phone is located in a shielding area or not is judged according to the fact;
(3) If the uplink signal strength exceeds the set power level threshold, the GSM mobile phone is judged to be located in the shielding area, and for the GSM mobile phone judged to be located in the shielding area, shielding interference signals with the same time slot are transmitted in the shielding transmission period, so that the strength of the interference signals is larger than the strength of uplink signals transmitted by the mobile phone, the receiving of the base station is interfered, and the communication of the GSM mobile phone is interrupted.
2. The method of claim 1, wherein the uplink signal transmitted by the mobile phone is screened from other screened interference signals in the screened area before the screened interference signals in the same time slot are transmitted; further detecting and identifying whether the uplink signal strength reaches a set power level threshold for the uplink signal determined to be transmitted by the mobile phone; the next operation is suspended for the other signals determined to be the shielding interference signals.
3. The method according to claim 1, wherein when other shielding interference signals exist in the shielding area, the identifying and detecting period is further used for identifying uplink signals transmitted by the mobile phone from other shielding interference signals in the shielding area, and further detecting whether the uplink signal strength reaches a set power level threshold.
4. The method of masking GSM handset signals located in a masked area according to claim 2, wherein the transmission frequencies of physically adjacent ones of the masked interfering signals are different in the masked area.
5. The method for shielding GSM mobile phone signals located in the shielded area according to claim 1, wherein an uplink time slot training method is adopted:
before the interference signal of the same time slot is transmitted, the uplink time slot boundary of the uplink carrier of the mobile phone and the time slot length are obtained, wherein the time slot boundary comprises a time slot starting boundary and a time slot ending boundary, and the uplink time slot boundary and the time slot length form an uplink time slot period.
6. The method of claim 5, wherein in the uplink slot training method, the slot training periods of the slot training base stations are utilized to mask all handsets under one base station, then the slot training periods of handsets corresponding to another base station are found, and all handsets under all different base stations in the mask area are masked in order.
7. The method of claim 1, wherein the center frequency of the transmitted simultaneous slot interference signal is offset from the center frequency of the GSM handset carrier signal by a certain amount.
8. A method of screening GSM handset signals located in a screening area according to any one of claims 1 to 7, characterized in that the uplink signals of the GSM handset are obtained by means of diversity reception.
9. The shielding system for the GSM mobile phone signals in the shielding area is characterized by comprising an uplink receiving antenna, a filter, a power detection comparator and an interference transmitter; the uplink signal in the shielding area is captured by an uplink receiving antenna and then is filtered by a filter and then is transmitted to a power detection comparator, the uplink signal transmitted by the GSM mobile phone has at least one uplink time slot period, the uplink time slot period comprises a recognition detection period and a shielding transmission period, whether the strength of the uplink signal reaches a set power level threshold or not is detected and recognized in the recognition detection period, and whether the GSM mobile phone transmitting the uplink signal is positioned in the shielding area is judged; if the uplink signal strength exceeds the set power level threshold, the GSM mobile phone is judged to be located in the shielding area, and for the GSM mobile phone judged to be located in the shielding area, the power detection comparator sends signals to the interference transmitter in the shielding transmission period to inform the interference transmitter of a time slot interference signal with the transmission strength larger than the uplink signal strength transmitted by the GSM mobile phone so as to shield the GSM mobile phone.
10. The screening system for GSM handset signals located within the screening area according to claim 9, wherein said filter includes a carrier filter module for filtering the uplink signals; the signal in the shielding area is captured by an uplink receiving antenna, filtered by a carrier wave filtering module and then transmitted to a power detection comparator so as to judge whether the signal is a mobile phone signal, and for judging the mobile phone signal, whether the signal strength of the mobile phone signal reaches a set power level threshold or not is detected, and whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged; for a cell phone determined to be located in the shielded area, the power detection comparator sends a signal to the interference transmitter informing the interference transmitter to transmit the co-time slot interference signal to shield the cell phone.
11. The shielding system for GSM handset signals located within a shielded area according to claim 10, wherein said filter further comprises a shielded interfering signal filtering module for filtering signals transmitted by other shields within the shielded system; the signal in the shielding area is captured by the uplink receiving antenna, and then is respectively filtered by the carrier wave filtering module and the shielding interference signal filtering module and then is transmitted to the power detection comparator to judge whether the signal is a mobile phone signal, and for judging the mobile phone signal, whether the signal strength of the mobile phone signal reaches a set power level threshold or not is detected, and whether the mobile phone transmitting the uplink signal is positioned in the shielding area is judged.
12. The shielding system for GSM handset signals located within a shielded area according to claim 11, wherein the carrier filter module and the shielded interfering signal filter module each have different center frequencies and bandwidths of operation.
13. The screening system for GSM handset signals located within the screening area according to claim 12, wherein the center frequency of the interference signal transmitted by the interfering transmitter is offset from the center frequency of the GSM handset carrier signal by a certain amount.
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| PCT/CN2019/080323 WO2020024602A1 (en) | 2018-07-26 | 2019-03-29 | Gsm mobile phone signal blocking method and system |
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| CN108737015B (en) * | 2018-07-26 | 2023-08-15 | 浙江三维通信科技有限公司 | Method and system for shielding GSM mobile phone signals |
| CN111970066B (en) * | 2020-08-14 | 2022-08-02 | 浙江三维通信科技有限公司 | Power detection method and device, storage medium and electronic device |
| CN112511262B (en) * | 2020-11-23 | 2022-05-06 | 浙江三维通信科技有限公司 | Cooperative shielding method, shielding system, storage medium and electronic device |
| CN112910599B (en) * | 2021-02-02 | 2022-10-28 | 安徽中屏科技有限公司 | Cheating interference feedback system based on multi-dimensional analysis |
| CN113132053B (en) * | 2021-04-19 | 2023-02-21 | 浙江三维通信科技有限公司 | Control system signal transmitting method and device, storage medium and electronic device |
| CN113572566A (en) * | 2021-06-30 | 2021-10-29 | 广州市瀚云信息技术有限公司 | Control method and device of movable shielding device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102739337A (en) * | 2012-06-06 | 2012-10-17 | 广州市瀚云信息技术有限公司 | Device and method for shielding mobile phone signal by time division synchronous control |
| CN103701555A (en) * | 2014-01-13 | 2014-04-02 | 泉州市华众电子科技有限公司 | Method and system for reducing false alarm rate of cell phone signal detecting and shielding system |
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| US6591109B2 (en) * | 2001-08-17 | 2003-07-08 | Interdigital Technology Corporation | Cross cell user equipment interference reduction in a time division duplex communication system using code division multiple access |
| US9819441B2 (en) * | 2013-01-21 | 2017-11-14 | Spectrum Effect, Inc. | Method for uplink jammer detection and avoidance in long-term evolution (LTE) networks |
| EP3058787B1 (en) * | 2013-10-16 | 2018-12-26 | Telefonaktiebolaget LM Ericsson (publ) | Resource utilization for uplink transmission based on indicated interference |
| CN108737015B (en) * | 2018-07-26 | 2023-08-15 | 浙江三维通信科技有限公司 | Method and system for shielding GSM mobile phone signals |
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|---|---|---|---|---|
| CN102739337A (en) * | 2012-06-06 | 2012-10-17 | 广州市瀚云信息技术有限公司 | Device and method for shielding mobile phone signal by time division synchronous control |
| CN103701555A (en) * | 2014-01-13 | 2014-04-02 | 泉州市华众电子科技有限公司 | Method and system for reducing false alarm rate of cell phone signal detecting and shielding system |
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