Which of the following descriptions about AP and antenna selection is correct? (Multiple choice)

Question

Options

• AIn rail transit scenarios, vehicle-to-ground communication generally uses indoor APs and indoor
• BIn outdoor scenarios, outdoor APs and outdoor antennas with higher protection levels and certain
• CIn indoor scenarios, indoor APs and indoor antennas are generally used to achieve signal
• DIn the rail transit scene, the coverage of the carriage generally uses outdoor APs and antennas

• A
  16% (5)
• B
  78% (25)
• D
  6% (2)

Explanation

B and C are correct because the core principle is matching equipment to environment: outdoor scenarios demand APs and antennas with higher IP-rated protection levels (e.g., IP67/IP68) to withstand rain, dust, and temperature extremes, while indoor scenarios use standard indoor-rated APs and antennas suited for controlled environments. These two options correctly apply equipment to environment.

Option A is wrong because rail transit vehicle-to-ground (wayside/trackside) communication occurs in outdoor conditions - the equipment mounted along the track must handle the elements, so outdoor APs and antennas are required, not indoor ones.

Option D is wrong because it reverses the logic for in-carriage coverage: the interior of a train carriage is functionally an indoor environment, so passenger WiFi inside the carriage uses indoor APs and antennas, not outdoor ones.

Memory tip: Think "A and D swap the rail transit scenarios." In-carriage = indoor gear (passengers are sheltered); trackside/vehicle-to-ground = outdoor gear (exposed to weather). A and D each put the wrong equipment type in the wrong rail transit location, making them both incorrect.

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