Intelligent Reflecting Surface with Power Splitting Aided Symbiotic Radio Networks

The performance of symbiotic radio (SR) networks can be improved by equipping secondary transmitters (STs) with intelligent reflecting surfaces (IRSs). Since the IRS power consumption is a non-negligible issue for STs, we consider an IRS assisted SR system where the IRS operates under power splitting (PS) mode. We aim at minimizing the IRS power consumption for the ST under the quality of service constraints for both primary and secondary transmissions by optimizing the transmit beamforming, the reflect beamforming and the PS factor. The optimization problem is non-convex. To tackle it, an algorithm is proposed by employing the block coordinate descent, semidefinite relaxation and alternating direction method of multipliers techniques. Simulation results demonstrate the efficiency and effectiveness of the proposed algorithm.