Analog turbo codes: A chaotic construction

This paper proposes a novel construction of analog codes based on nonlinear chaotic dynamical systems in general and the tent map in particular. In light of the importance of the symbolic coding in estimating tent chaos, the proposed construction exploit useful ideas of interleaving and parallel concatenation from classical coding theory to protect symbolic coding and subsequently chaotic states. The resultant new codes, dubbed chaotic analog turbo (CAT) codes, extend Chen-Wornell codes, in a spirit close to that of digital turbo codes extending digital convolutional codes. A new sequence detection method that improves the existing backward detection method is also developed. Through analysis and simulations, it is shown that CAT codes can noticeably outperform the existing analog ones.