College candidates may pass questions due to 5G signal shielding loopholes

On June 8, 2021, the Education Bureau of Huangpi District, Wuhan City issued a report on the fraud of the candidate Wu Moumou. The candidate Wu Moumou illegally brought a mobile phone into the examination room to take the test paper, and the invigilator was guilty of entry security check and invigilator dereliction of duty. The Huangpi District Admissions Office responded to the reporter that it may be due to loopholes in the 5G signal shielding that the candidate can upload the test questions on his mobile phone. It is a well-known iron law that mobile phones cannot be brought into the examination room; but according to common sense, cell phone signal jammers are generally installed in the examination room, and even a mobile phone brought in by chance is a "brick".

Old blocker or unable to block 5G signal?

"5G is a newly launched network system in recent years, which uses some new radio frequency bands, and many old-fashioned jammers do not yet support shielding 5G signals.

According to the division of 5G frequency bands, China Telecom and China Unicom mainly use 100MHz spectrum resources in the 3.5GHz band for 5G, while China Mobile mainly uses 160MHz in the 2.6GHz band and 100MHz in the 4.9GHz band.

The working principle of the signal jammer is to use higher power and release stronger signals in the frequency band of the corresponding mobile network to suppress the interference of normal signals, so as to achieve the purpose of shielding.

"The first possibility is that the 5G signal may not be within the working range of the signal jammer used on site; the second possibility is that the 5G signal itself has relatively strong anti-interference ability, and the signal jammer failed to suppress the interference successfully." .

At present, communication technology is constantly being upgraded, and the 5G signal system is also different from the original 4G system. It is also possible that old models of interference equipment cannot completely interfere with the 5G signal.

It is not difficult to make up for this loophole. Confirm with the telecommunications department in advance what types of signals are near the test room, and then deploy new types of jammers in a targeted manner.

The power of the shield will also affect the effect of signal shielding. In addition, the shielding effect of the jammer has a lot to do with the signal strength of the site. If the signal strength is too high, the signal may not be suppressed, so a larger power jammer needs to be considered.

According to the official Weibo announcement of Wuhan Huangpi District Education Bureau, on the evening of June 7, after the examination area organized the examination room video playback, it was confirmed that the examinee Wu Moumou illegally brought a mobile phone into the examination room to shoot the examination papers, and the invigilators had problems of entry security check and invigilator dereliction of duty. At the same time, the candidates who violated the regulations will be disqualified from the examination, and the results of each stage and subject they have registered for the examination will be invalid, and further processing will be made according to the follow-up investigation results.

On the afternoon of the 8th, the Hubei Provincial Radio Management Department responded to the media and stated that a special class had been formed to investigate the matter. If it was determined that the candidate used radio equipment to transmit cheating, it would be dealt with in accordance with the law.