What is a slot time in an IEEE 802.11 WLAN?

• A. A random backoff period chosen by a station.
• B. A standard period of time which is preprogrammed into the radio and determined by the WLAN technology being utilized.
• C. The maximum duration of a data frame.
• D. The time between beacon transmissions.

Answer: (B)

Slot time is a fixed time unit defined by the physical layer for how 802.11 stations count and wait before attempting to transmit. It isn’t chosen randomly each time; instead, the backoff countdown uses this standard unit. The actual waiting period a station experiences is the number of backoff slots it has been assigned multiplied by the slot time. Different WLAN technologies define different slot times, which is why it’s described as a standard period preprogrammed into the radio and determined by the PHY. This timing unit underpins how CSMA/CA coordinates access to the wireless medium, along with other timings like SIFS and DIFS.