A Hybrid Digital-Analog Chaotic Code

Traditional analog chaotic codes suffer from the vulnerability of signs at the receiver, and this situation deteriorates at low signal-to-noise ratio (SNR). In order to solve this problem, this letter proposes a hybrid digital-analog chaotic code (HDACC), which uses chaotic states (analog value) and part of their signs (digital value) together as parity codewords. These signs are further encoded in a digital way. We derived the theoretical decoding mean square error (MSE) of HDACC over additive white Gaussian noise channel and gave the optimal digital/analog codewords allocation. Simulation results demonstrate that the derived theoretical MSE matches very well with simulated MSE curves. Evaluations show that HDACC outperforms existing related works in a wide SNR range.