A class of multirate convolutional codes by dummy bit insertion

We present a method to construct lower rate codes from a known high rate code by inserting known dummy bits into the information bit sequence before encoding. Like other multirate codes based on puncturing or repetition, this new class of codes can adjust the amount of protection given to the information bits, and can be decoded using the same decoder as for the mother codes. Specifically, we focused on the recursive systematic insertion convolutional (RSIC) codes. Our analysis and simulation results show that the proposed RSIC code achieves a performance which is comparable to the corresponding optimal recursive systematic repetition convolutional (RSRC) code.