Which of the following statements about antenna gain is correct?

• A. The higher the gain of the antenna, the higher the degree of signal convergence
• B. The selection of the antenna should meet the requirements of the coverage scenario, not the bigger the gain, the better
• C. The higher the gain of the antenna, the better, using the antenna with large gain can obtain greater transmit power
• D. The larger the antenna gain, the smaller the coverage angle

first. The multi-frequency combiner should be able to support the required working frequency band, and the closer its passband frequency is to the working frequency of the wireless system, the better, without redundant passband, so as to ensure the best effect; For combiners, the isolation between ports is generally greater than 80dB, which can minimize the interference between different systems.
The above statement is correct.

• A. error
• B. correct

During a wireless network survey, which of the following statements is true:

• A. When deploying multiple APs indoors, in order to meet the wireless application requirements of a certain user density, it is necessary to select the appropriate AP installation location, installation method, transmission power, etc., so as to reduce the visible signal in the three-dimensional space as much as possible. quantity.
• B. When deploying multiple APs indoors, in order to ensure better signal strength indicators, the APs should work at the maximum transmit power, and attention should be paid to the channel division between APs.
• C. When conducting wireless network survey, it is necessary to ensure that the coverage is the same as the actual application demand area. When the signal coverage is affected by obstacles and the wireless signal coverage cannot meet the actual application demand area, it needs to be adjusted in time. Deployment scenario.
• D. When planning signal coverage in three-dimensional space, the problem of signal leakage across floors is unavoidable. Therefore, the degradation of wireless link quality caused by signal leakage needs to be considered and optimized.

The correct description of the cupid positioning function is

• A. Compared with the RSSI value, it is greatly affected by the environmental factors in the transmission process, and the environmental influence on the RTT value is relatively small.
• B. It adopts the working principle similar to sonar, the clocks of receiving and sending are all from the clock of the local AP, which avoids the complex clock synchronization problem of one-way measurement (such as GPS system).
• C. The high-precision local clock ensures accurate measurement results and ultimately improves positioning accuracy.
• D. The CUPID system adopts the technical route based on the electromagnetic wave transmission time difference RT. In the case of no sampling, a more accurate and stable positioning effect is achieved.

The following statement is correct

• A. WLAN dual-band combiner is used for capacity expansion, which is fast in implementation and low in cost. It can quickly double the number of access users in hotspot areas, and can easily deploy functions such as load balancing.
• B. WLAN and PHS have similar frequency bands and air attenuation. When the power of the equipment is the same, the coverage is similar, which provides favorable conditions for the co-site construction of WLAN and PHS.
• C. When covering multiple floors, the channel setting should consider the signal interference in the three-dimensional space.
• D. The user isolation function can reduce the impact of broadcast packets and user traffic on the network, and also avoid some ARP attacks, making the wireless network stable and safe to use.