Which component of frequency hopping spread spectrum (FHSS) system creates more overhead than any similar component in a direct sequence spread spectrum (DSSS) system?

• A. Preamble.
• B. The interframe spacing.
• C. Forward error correction.
• D. Synchronization sequence.

Answer: (B)

The main idea here is how FHSS adds timing overhead due to hopping between frequencies. In FHSS, the transmitter switches channels to follow the hopping pattern, and the receiver must retune and settle on the new frequency for each hop. To avoid interference between successive hops and to give the radio enough time to switch and stabilize, a guard-like interframe spacing is inserted between frames. This interframe gap grows with the hopping rate and the required settling time, making it a larger source of overhead in FHSS than in DSSS, where everything stays on a single frequency and the frame can carry its preamble, synchronization, and error correction without the extra hop-related gaps. Preambles, synchronization sequences, and even some FEC are overhead in either scheme, but they don’t scale with channel hopping in the same way; the interframe spacing is the part that becomes noticeably larger specifically because of frequency hopping.