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On June 8, 2021, the Huangpi District Education Bureau of Wuhan City issued a report on the fraud of candidate Wu XX. Candidate Wu XX illegally brought his mobile phone into the examination room to take pictures of the test papers.

Subsequently, the Huangpi District Admissions and Examinations Office responded to the reporter, saying that there may be a loophole in the 5G signal shielding, which allowed the candidate to upload the test questions with his mobile phone.

Why is there a loophole in 5G signal shielding?
We all know that in some special scenarios, full-band frequency jammers are needed to interfere with mobile phone signals to prevent leaks or cheating. It will be blocked by full-band jammers.
And the most typical of these special scenes is the college entrance examination room——
The college entrance examination is almost one of the most important things in the life of Chinese people. Ensuring its fairness has become an important task of education bureaus in various places. In order to ensure fairness, various anti-cheating methods will be adopted in the college entrance examination venue. Check, fingerprint unlock, etc.
Nowadays, various electronic devices emerge in endlessly, and some of them can even evade detection after being disguised. Candidates who cheat are to bring electronic devices into the examination room to output the questions to the outside world, and then people outside the examination room help answer the questions to achieve the purpose of cheating. The basis of all this That is - must spread through the network!
In this case, the full-band frequency cell phone blocker is particularly important. How does signal shielding work?
To put it simply, taking a mobile phone as an example, the mobile phone needs to communicate with other devices outside the examination room through a signal tower, while wireless communication needs to be carried by electromagnetic waves. According to the characteristics of electromagnetic waves, the devices on both sides need to be within a certain frequency range. Sending and receiving, so the full-band jammer is to affect the frequency of your electronic equipment so that the frequencies of the two parties are different, so as to achieve the effect of shielding.

The principle is very simple and the operation is very convenient. So why did this incident of candidates uploading exam questions and searching for answers happen? Is it the pot of 5G?
In my opinion, the problem lies in: the staff in the examination room, especially the staff responsible for signal shielding, are too rigid!
Generally speaking, the full-band frequency jammer in the examination room shields the mobile phone by interfering with the mobile phone signal in the specified band. The spectrum range of the mainstream 4G network is generally between 1700MHz and 2600MHz. For example, China Mobile’s 4G is mainly between 2320-2370 MHz and 2575-2635 MHz two major frequency bands, while China Telecom is in two major frequency bands of 1755-1785 MHz and 1850-1880 MHz, and China Unicom is in 1955-1980 MHz and 2145-2170 MHz.
The examination room only needs to conduct electronic interference on the above frequency bands, and the 4G network of the mobile phone cannot be connected, so as to achieve the function of shielding the signal.
But the problem is that the frequency band of the 5G network is relatively higher, and the staff in the examination room who stick to the rules are likely to forget the new thing of 5G, which leads to the 5G signal not being blocked.
For example, China Mobile's 5G is mainly deployed in the 2515~2615MHz frequency band, China Telecom's 5G is deployed in the 3400MHz-3500MHz, and China Unicom's 3500MHz-3600MHz. Since the 5G frequency bands of China Telecom and China Unicom are continuous, the two have made it clear that they will jointly build and share 5G wireless access networks based on the continuous 200MHz bandwidth of 3400MHz-3600MHz.
Judging from the distribution of the above frequency bands, we even have reason to suspect that the cheating candidate is likely to use the number card of China Telecom or China Unicom. After all, the 5G frequency band of China Mobile is closer to the 4G frequency band, and the possibility of being missed is not high. Too high, and the 5G frequency bands of China Telecom and China Unicom are much higher than the mainstream frequency bands of 4G in the past, and there is indeed the possibility of being missed.

Therefore, this matter itself may be very serious, but from a technical point of view, there is no fatal loophole, it is just human negligence, ignoring that 5G has become popular, and forgetting to add the 5G frequency band to the designated band of the full-band jammer . Or the full-band jammer installed in the examination room has not been upgraded or replaced in advance, and the 5G shielding has not been upgraded or replaced with a full-band frequency jammer capable of shielding 5G signals.