Revolutionizing Symbiotic Radio: Exploiting Trade-Offs in Hybrid Active-Passive Communications

Symbiotic radio (SR), a novel energy- and spectrum- sharing paradigm of backscatter communications (BC), has been deemed a promising solution for ambient Internet of Things (A-IoT), enabling ultra-low power consumption and massive connectivity. However, A-IoT devices utilizing BC suffer from low transmission rates, which may limit the applications of SR in A-IoT scenarios with data transmission requirements. To address this issue, in this article, we introduce hybrid active-passive communications (HAPC) into SR by exploiting trade-offs between transmission rate and power consumption. First, we present an overview of novel BC paradigms, including ambient BC and SR. Then, a novel HAPC-enabled SR is proposed to enhance the transmission rate of A-IoT devices. Furthermore, within this paradigm, we investigate the resource allocation scheme and present preliminary research results. Simulation results show that the transmission rate and energy efficiency of A-IoT devices in the proposed HAPC-enabled SR surpass that of traditional SR. Finally, we discuss open issues related to HAPC-enabled SR.