Serial concatenation of interleaved codes: performance analysis, design, and iterative decoding

• Published in: IEEE transactions on information theory Vol. 44; no. 3; pp. 909 - 926
• Main Authors: Benedetto, S., Divsalar, D., Montorsi, G., Pollara, F.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.1998; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Block codes; Codes; Concatenated codes; Convolutional codes; Cryptography; Error probability; Interleaved codes; Iterative decoding; Maximum likelihood decoding; Performance analysis; Propulsion; Turbo codes
• ISSN: 0018-9448; 1557-9654
• DOI: 10.1109/18.669119

A serially concatenated code with interleaver consists of the cascade of an outer encoder, an interleaver permuting the outer codewords bits, and an inner encoder whose input words are the permuted outer codewords. The construction can be generalized to h cascaded encoders separated by h-1 interleavers. We obtain upper bounds to the average maximum-likelihood bit error probability of serially concatenated block and convolutional coding schemes. Then, we derive design guidelines for the outer and inner encoders that maximize the interleaver gain and the asymptotic slope of the error probability curves. Finally, we propose a new, low-complexity iterative decoding algorithm. Throughout the paper, extensive comparisons with parallel concatenated convolutional codes known as "turbo codes" are performed, showing that the new scheme can offer superior performance.