부산대학교 도서관

In this letter, we propose a cooperative commensal and parasitic (CCP) scheme for symbiotic radio (SR) communication systems, which exploits the cooperation between the commensal SR (CSR) and parasitic SR (PSR) setups for enhancing communication performance. Specifically, two backscatter devices passively deliver their information by reflecting primary signals from the base station to the primary user (PU) in the CSR and PSR setups, respectively. The involvement of CSR can offset the interference of PSR to the PU, thereby improving the performance of primary transmission. In the meanwhile, the utilization of PSR guarantees diversified quality of service requirements for secondary transmissions. We further optimize the transmit beamforming at the BS to maximize the achievable primary rate at the PU. To solve the formulated problem, an iterative algorithm is first conceived to find the globally optimal solution. However, this solution comes with high complexity. Thus, an algorithm with low complexity is designed to obtain a solution with satisfactory accuracy. Numerical results verify the effectiveness of the proposed CCP scheme.