Non-Line-of-Sight Channel Performance of Plane Spiral Orbital Angular Momentum MIMO Systems

The performances of plane spiral orbital angular moment (OAM)-based MIMO (PSOAM-MIMO) systems are investigated in a non-line-of-sight (NLoS) channel. Two analytical models, known as specular reflection model and circular scattering model, are applied to evaluate the reflection and scattering effects of wave propagating in the NLoS channels. The performances of the PSOAM-MIMO system in the NLoS channel are compared with those of the conventional MIMO system and in LoS channel. It is found that the capacity gain of the PSOAM-MIMO over MIMO is mainly determined by a direct path. In the NLoS channel, the capacity gain of PSOAM-MIMO over MIMO decreases compared with that in LoS, however, the multi-path effects improve the absolute capacity of PSOAM-MIMO system, and the worst case are comparable with those in an MIMO system. As a result, the PSOAM-MIMO system demonstrates the strong robustness in wireless communications.