What is the purpose of interleaving in digital communications?

• A. Distributes errors over time to improve correction.
• B. Compresses data.
• C. Increases noise.
• D. Modulates the carrier.

Answer: (A)

Interleaving spreads errors over time to improve error correction. By reordering the transmitted symbols, a burst of errors that hits a short time span is dispersed across many different codewords at the receiver. This means each codeword ends up with only a few errors, which the error-correcting code can typically fix, instead of having a single codeword heavily corrupted. In other words, burst errors that would overwhelm correction become more manageable, boosting reliability. Interleaving doesn’t compress data, increase noise, or modulate the carrier; its job is to turn clustered disturbances into a pattern that the ECC can handle more effectively. Keep in mind that it adds latency due to the buffering needed to reorder symbols.