What causes the hidden node problem in a wireless LAN?

What causes the hidden node problem in a wireless LAN?

• A. A client can receive signals from an AP but an obstacle prevents the client from receiving signals from other clients connected to the network.
• B. A client cannot hear the AP.
• C. The AP operates on a different channel than the client.
• D. Too many clients causing collisions on a single channel.

Answer: (A)

Hidden node problems happen when two wireless devices can both reach the access point, but cannot hear each other because an obstacle blocks their direct link. Because each device can hear the AP, they think the channel is free and they both start transmitting. The AP ends up receiving overlapping transmissions from both devices, causing a collision and reducing network performance. This is why the scenario fits: one client can receive from the AP, but an obstacle prevents it from hearing the other clients, creating the hidden node situation and collisions at the AP. In contrast, if a client can’t hear the AP, there’s no usable link to begin with. If the AP and client are on different channels, they won’t communicate at all. And while many clients on one channel can cause collisions, that describes general contention, not the specific hid­den-node condition where two senders can’t hear each other.

Hidden node problems happen when two wireless devices can both reach the access point, but cannot hear each other because an obstacle blocks their direct link. Because each device can hear the AP, they think the channel is free and they both start transmitting. The AP ends up receiving overlapping transmissions from both devices, causing a collision and reducing network performance. This is why the scenario fits: one client can receive from the AP, but an obstacle prevents it from hearing the other clients, creating the hidden node situation and collisions at the AP.

In contrast, if a client can’t hear the AP, there’s no usable link to begin with. If the AP and client are on different channels, they won’t communicate at all. And while many clients on one channel can cause collisions, that describes general contention, not the specific hid­den-node condition where two senders can’t hear each other.