A Reliable and Energy Efficient Superposition Modulation and SVD-Aided Detection Based Multiuser OFDM-DCSK Paired Transceiver for IoT Devices

In order to meet increasing demands of higher energy efficiency and better reliability performance for the multiuser Internet of things (IoT) secure communications, in this paper, we design a reliable and energy efficient superposition modulation (SM) and singular value decomposition (SVD) detection based multi-user orthogonal frequency division modulation-based differential chaos shift keying (SM-MU-OFDM-DCSK) transceiver for IoT devices. At the transmitter, we propose to superimpose and overlap the information-bearing chaotic signals for higher energy efficiency. Since the chaotic modulated signals of each user share identical reference chaotic signals, the transmitted superimposed signal matrices have the low-rank property. Then at the receiver, we apply the SVD-aided detection to recover these low-rank signals, which can suppress the noise to attain better reliability performance. Moreover, we prove that the proposed design can achieve the maximum likelihood detection performances. Furthermore, we derive the theoretical bit rate, energy efficiency and bit error rate expressions over additive white Gaussian noise (AWGN) channel. Simulation results are then provided to validate the theoretical derivations. Subsequently, the simulated performances over AWGN and fading channels are investigated to show that higher energy efficiency and better reliability performances than benchmark schemes can be achieved in industrial IoT scenarios.