Choosing the Right Approach for Signal Shielding System in Examination Halls

Comparing the Benefits and Drawbacks of Indoor Signal Distribution and Cellular Networking

Introduction: As the annual college entrance examination (known as Gaokao) in June and the secondary school entrance examination (known as Zhongkao) in July approach, many schools that serve as examination centers have already begun the construction of standardized examination halls. According to the standards for constructing standardized examination halls, the installation of a full-band signal shielding system is a necessary component. However, clients often find themselves faced with two technical approaches when it comes to the system’s design and equipment selection. The first approach involves using conventional low-power full-band signal shielding devices, employing cellular networking to cover the signal shielding. The second approach utilizes high-power shielding equipment with indoor signal distribution to cover the signal shielding within each classroom. This article aims to explore how clients should choose between these two options and the advantages of using indoor signal distribution in the signal shielding system.

Advantages of Indoor Signal Distribution:

When employing indoor signal distribution, the main equipment of the full-band signal shielding system is installed in a relatively concealed location, making it easier to maintain and repair individually. Typically, small-sized omnidirectional antennas are used at the antenna end, mounted on the ceiling of corridors or classrooms. These antennas are small in size and inconspicuous. If there is a gypsum board ceiling, they can even be installed inside the ceiling, achieving complete concealment. For the construction of a signal shielding system in a teaching building, fewer main units are required. Usually, one main unit can handle the signal shielding of multiple classrooms on two or three floors.

Drawbacks of Indoor Signal Distribution:

However, if the indoor signal distribution approach is chosen, the main units of the system are high-power devices, resulting in higher costs. The procurement cost of one high-power main unit is almost equivalent to that of dozens of low-power full-band signal shielding devices. For a teaching building with a height of 4-6 floors, at least two high-power main units are required. If the building is long, the number of main units needed may even double. This undoubtedly increases the construction cost significantly. Additionally, during the construction process of the indoor signal distribution approach, the remote transmitting antennas are connected in parallel to a main feeder line, which is ultimately connected to the system’s main unit. This means that there will always be cable connections between the main feeder line and the examination classrooms, requiring wiring and wall penetration work. Moreover, the signal gradually attenuates during transmission, meaning that the nearby antennas can receive and transmit stronger shielding signals, while the distant antennas experience a significant decrease in signal strength. This can result in varying levels of final shielding effectiveness in different examination classrooms within the full-band signal shielding system.


When it comes to choosing between cellular networking and indoor signal distribution for the construction of standardized examination halls, clients should carefully consider the advantages and drawbacks of each approach. While indoor signal distribution offers benefits such as easy maintenance, inconspicuous antennas, and fewer main units required, it also comes with the drawback of higher costs and potential variations in shielding effectiveness. Ultimately, the decision should be based on the specific requirements and budget constraints of each client.