On decoding methods for double‐encoding systems
Hideki Imai, Yasuji Nagasaka · Electronics and Communications in Japan (Part I Communications) · 1982
Abstract Double encoding is a method by which a new code is constructed by twofold encoding with two codes. Using this method, a code with excellent error‐correcting capabilities can be constructed from relatively simple codes. The decoding can also be made simpler compared with a single code with the same code length and the same error‐correcting performance. Both random and burst errors can be corrected. This paper describes a general, practical decoding method for use in a double‐encoding system. Algebraic decoding is used in both the first and the second stages, but the detailed information obtained in the first decoding is fully utilized in the second stage: the usual error‐correcting method is applied in the first decoding and a Chase algorithm is applied in the second decoding. A decoding system which is a practical simplification of the above method is also proposed. The proposed methods are compared with widely‐used conventional systems in terms of the decoding error rate; it is shown that the decoding error rate can drastically be improved.