Which component of frequency hopping spread spectrum (FHSS) systems creates more overhead compared to a similar component in direct sequence spread spectrum (DSSS) systems?

In frequency hopping spread spectrum (FHSS) systems, interframe spacing is essential for managing the timing of frequency changes and ensuring proper synchronization between the transmitter and receiver. This spacing allows time for the system to switch frequencies seamlessly. As a result, it introduces additional overhead in the form of timing gaps between data frames. In comparison, direct sequence spread spectrum (DSSS) systems utilize a continuous transmission method where the coding is applied directly to the data stream, which generally results in less overhead related to timing.

The interframe spacing in FHSS impacts the overall throughput of the system, as periods of no data transmission are required for the frequency shifts. This contrasts with DSSS, which maintains a more consistent data transmission due to its method of spreading the signal over a wider bandwidth without the need for gaps. Therefore, it's the increased interframe spacing in FHSS systems that contributes to more overhead compared to the direct transmission approach used in DSSS systems.

Other components like modulation index, signal coding, and data encryption do not inherently bring about this same level of timing overhead as interframe spacing does in the context of FHSS.