What causes the hidden node problem in a wireless local area network (WLAN)?

The hidden node problem in a wireless local area network (WLAN) arises when a client device can successfully communicate with an access point but is unable to detect other devices that are also communicating with the same access point. This situation typically occurs when obstacles—such as walls or physical barriers—prevent direct communication between two client devices. As a result, these clients may transmit data simultaneously to the access point without being aware of each other's presence, leading to collisions and data loss.

In this context, while noise, low signal strength, and access point overload are all potential issues that can affect network performance, they do not specifically relate to the hidden node problem. Excessive noise may lead to poor communication quality, low signal strength can degrade connectivity, and too many clients can overwhelm the access point. However, none of these scenarios directly describe the conditions under which the hidden node phenomenon occurs, which is fundamentally about one client being "hidden" from another due to physical obstructions. Thus, the correct identification of the hidden node problem is linked to the inability of devices to communicate with each other while still being connected to the same access point.