Design of Orbital Angular Momentum Module in 5G Open Source Radio Access Network

Orbital angular momentum (OAM) has obtained intensive interest among free-space optics and radio-frequency communications due to the mode orthogonality. OAM can realize multiplex transmission of large-capacity data on the same time-frequency physical resource. Combining OAM with existing mobile communication technologies is expected to meet the requirements of the next generation radio access network (RAN) for higher bandwidth and spectrum efficiency. In this paper, we propose two implementation solutions for the OAM module based on OpenAirInterface (OAI) in different scenarios, including common multiplexing and precoding communication. Specifically, the common multiplexing solution consists of three submodules: OAM multiplexing, demultiplexing, and channel submodules, which consider additive white Gaussian noise (AWGN) and atmospheric turbulence. The test results show that the designed OAM module can improve the anti-interference performance without increasing the cost and consumption of the original system. The OAM module supports the simulation and verification of the OAM technique combined with the 5G RAN protocol stack.