OAM Transmission in Sparse Multipath Environments with Fading

Orbital angular momentum (OAM), which has attracted much attention recently, is a potential technology to achieve high capacity for future wireless communications. In existing literatures, the OAM-based transmission is assumed to be used in ideal line-of-sight (LoS) scenarios. The non-line-of-sight (NLoS) scenarios, however, is more practical for wireless communications. In this paper, we focus on OAM-based transmission in sparse multipath environments. We build the OAM-based transmission model for Rician fading channels and derive the corresponding capacity of radio vortex wireless communications. Also, we analyze the key parameters of OAM-based transmission in sparse multipath environments. Conducted numerical results verify that the capacity of OAM-based transmission is superior to that of multiple-input-multiple-output (MIMO) based transmission in sparse multipath environments.