A dead zone (Wi-Fi dead zone) is an area within a wireless LAN location where Wi-Fi does not function, typically due to radio interference or range issues.
Because Wi-Fi is a radio signal the same things that disrupt radio tend to affect Wi-Fi. Some interference is caused by thick walls or metallic barriers; dead zones can also be caused by other radio sources, such as competing Wi-Fi networks, electronics and other sources of electromagnetic interference (EMI).
Cellular phone access points can hand off users to the next available access point, but Wi-Fi networks don’t generally have that ability. This lack makes loss of connectivity on Wi-Fi a much more disruptive issue, often requiring user attention to reconnect after even a momentary loss.
Dead zones can be mitigated by careful network setup and consideration of the location, its physical layout and makeup and its potential sources of interference. There are also site survey tools that help you chart out your Wi-Fi network’s strong, weak and dead zones. A site survey can help locate interference sources and see how access point distribution could be adjusted for better coverage.