Achieving Unequal Error Protection via Woven Codes: Construction and Analysis

In this paper several rate R = 2/5 convolutional encoding matrices with four states are used to illustrate how unequal error protection can be achieved for the different positions in the code sequences as well as in the information sequences. Free outputand input-distances and active burst outputand input-distances are computed. Typically a single code cannot combine a large free outputor input-distance with a steep slope. A constructive way to obtain powerful unequal coding schemes that provide both large distances and steep slopes is to combine several constituent encoders. Various woven schemes are studied and lower bounds on the active burst outputand input-distances are derived.