Nonlinear Phenomena in Turbo Decoding Algorithms
The turbo decoding algorithm is a high-dimensional dynamical system parameterized by a large number of parameters (for a practical realization the turbo decoding algorithm has more than 103 variables and is parameterized by more than 103 parameters). In this chapter we treat the turbo decoding algorithm as a dynamical system parameterized by a single parameter that closely approximates the signal-to-noise ratio (SNR). A whole range of phenomena known to occur in nonlinear systems, such as the existence of multiple fixed points, oscillatory behavior, bifurcations, chaos, and transient chaos are found in the turbo decoding algorithm. We develop a simple technique to control transient chaos in the turbo decoding algorithm and improve the performance of the standard turbo codes.
KeywordsLyapunov Exponent Periodic Point Chaotic Attractor LDPC Code Turbo Code
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