An Interactive Visual Debugging Tool for Viterbi Trellis Decoding of 2D Codes

An interactive visual debugging tool (VDT) has been designed and implemented for trellis related analysis of two-dimensional (2D) block codes. The VDT allows users to select number of parameters for code construction by providing a user friendly interactive interface, and then dynamically it calculates rest of parameters and determines essential trellis components internally without user intervention. The user interface provides visual aids to view number of useful data structures, such as encoded data sequence, the tool for introducing (hard-decision and soft-decision) errors at specific 2D code positions, the received sequence at the output the channel, and the decoded data sequence after trellis decoding. The tool allows users to trace decoding process step-by-step and view detailed workouts at each node of the trellis. This visually rich interactive VDT can be used in teaching trellis related concepts in a classroom, and also it can be employed by researchers and coding professionals for code design and analysis