Implementation of chaotic frequency modulation based spread spectrum communication system in software-defined radio

This paper is devoted to the software-defined radio (SDR) implementation of frequency modulated antipodal chaos shift keying (FM-ACSK) communication system. This novel and perspective class of spread-spectrum systems employs chaotic synchronization for the acquisition and tracking of the spreading signal and does not need resource-demanding cross-correlation usually employed for this purpose. This paper aims to present how to implement a full FM-ACSK communication system, including additional synchronization circuitry, using SDR and MATLAB Simulink. Moreover, for the first time, the performance of FM-ACSK in real conditions using over-the-air transmission between two SDRs is assessed. In the paper, it is shown that the presented class of the spread spectrum systems demonstrates good performance in low signal-to-noise ratio (SNR) conditions, and it is immune to large carrier frequency offset (CFO). The proposed solution fits well to low-speed long-range wireless sensor network (WSN) applications.