Marker Guess & Check Plus (MGC+): An Efficient Short Blocklength Code for Random Edit Errors

Motivated by DNA-based data storage, we focus on the design of short blocklength codes for correcting random edits, i.e., deletions, insertions, and substitutions. Building on the recently introduced Guess & Check Plus (GC+) code, we propose Marker-GC+ (MGC+), which inserts periodic markers and leverages a marker-aided decoding algorithm to reduce complexity and enhance error correction capability. Our decoder combines trellis-based offset estimation with an informed guessing strategy to achieve these gains. Simulations demonstrate that MGC+ achieves higher code rates, lower decoding times, and improved reliability compared to existing codes.