Design of an Improved M-Ary DCSK-Aided Protograph-Coded Communication System

Differential chaos shift keying (DCSK) is a promising communication technique in the Internet of Things (IoT) scenario. Among various DCSK schemes,
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-ary DCSK schemes suit LDPC code especially well dispense with the channel state information in demodulator. However, traditional
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-ary DCSK decoder does not make full use of the information of the repeated chaotic signals. To solve this problem, we propose an improved decoder design using a novel initial chaotic signal estimation (ICSE) algorithm. The information of each repeated chaotic signal is utilized to estimate the original chaotic signal, hence provide the accurate log-likelihood ratio (LLR) and improve the error performance. To further boost the system performance, A novel protograph code is proposed using protograph extrinsic information transfer (P-EXIT) algorithm. Both analytical and simulated results show that both the improved decoder design and the proposed protograph code are competitive. The
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-ary protograph-coded DCSK system using our improved decoder with ICSE algorithm is a promising solution for low-power and low-complexity devices.