Secure and reliable IoT communications using nonorthogonal signals' superposition with dual-transmission

Ensuring secure communication for internet of things (IoT) has drawn much attention because of the limitation in the use of conventional cryptographic techniques owing to the unique features of IoT devices such as low complexity, lightweight computing, and power constraints. Physical layer security (PLS) has the potential to provide security solutions that are suitable for such applications. In this article, an efficient PLS approach is proposed for providing secure communication against external and internal eavesdroppers in a downlink multi-carrier IoT communication system. The system consists of a transmitter with a single active antenna (and a single radio frequency chain) that is trying to communicate with two single-antenna IoT devices in the presence of a passive eavesdropper. In the proposed algorithm, frequency selective channel based pre-coder matrices and dual-transmission approach are jointly employed to provide simple and secure communication without complex computational processing at the IoT devices. Simulation results showed that the proposed algorithm can provide security against internal and external eavesdroppers and is suitable for IoT devices.