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

Abstract

Differential chaos shift keying (DCSK) is a promising communication technique in the Internet of Things (IoT) scenario. Among various DCSK schemes, M -ary DCSK schemes suit LDPC code especially well dispense with the channel state information in demodulator. However, traditional M -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 loglikelihood 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 M -ary protograph-coded DCSK system using our improved decoder with ICSE algorithm is a promising solution for low-power and low-complexity devices.INDEX TERMS M -ary DCSK system, protograph LDPC codes, improved protograph decoder, chaotic signal estimation.