The orbital angular momentum (OAM) wireless communication technology is widely studied in recent literatures. But the atmospheric turbulence is rarely considered in analyzing the capacity of OAM-based millimeter wave (OAM-mmWave) communication systems. The OAM-mmWave propagated in the atmosphere environments is usually interfered by the atmospheric turbulence, resulting in the crosstalk among OAM channels, capacity degradation, etc. By taking into account the atmospheric turbulence effect, this paper proposes a new purity model and a new capacity model for the OAM-mmWave communication systems. Simulation results indicate that the OAM-mmWave propagation in the atmosphere environments is evidently interfered by atmospheric turbulence, where the capacity of the OAM-mmWave communication systems decreases with the increase of the transmission frequency.Index Terms-Atmospheric turbulence, orbital angular momentum, millimeter wave, capacity. In this paper the impact of atmospheric turbulence on the OAM-mmWave communication systems has been investigated. A new capacity model has been proposed for the OAM-mmWave communication systems considering the atmospheric turbulence effect. The contributions of this paper are summarized as follows: 1) A new purity model is proposed for OAM-mmWave communication systems considering the propagation characteristics of OAM-mmWave with the atmospheric turbulence. In general, the atmospheric turbulence arXiv:1909.04336v1 [eess.SP]

The Orbital Angular Momentum (OAM) wireless communication technology has received much attention in recent years for its natural orthogonality between different OAM states. Combining the OAM technology with the Orthogonal Frequency Division Multiplexing (OFDM) technology, we proposed a new OAM-OFDM wireless communication system to explore a new approach for enhancing the transmission capacity of the wireless communication system. Atmospheric turbulence is an important factor for influencing the capacity of the OAM-OFDM wireless communication system. In consideration of the effect of the atmospheric turbulence, we derived a crosstalk model of the proposed OAM-OFDM wireless communication system. Furthermore, a capacity model of the OAM-OFDM wireless communication system is proposed in consideration of the effect of atmospheric turbulence on both the OAM and OFDM signals. Compared with the conventional OAM wireless communication system, the capacity performance of the proposed OAM-OFDM wireless communication system is significantly improved and the average improvement is 751%. INDEX TERMS Orbital angular momentum, capacity, bit error ratio, orthogonal frequency division multiplexing.

The orbital angular momentum (OAM) wireless communication technique is emerging as one of potential techniques for the Sixth generation (6G) wireless communication system. The most advantage of OAM wireless communication technique is the natural orthogonality among different OAM states.However, one of the most disadvantages is the crosstalk among different OAM states which is widely caused by the atmospheric turbulence and the misalignment between the transmitting and receiving antennas. Considering the OAM-based multiple-input multiple-output (OAM-MIMO) transmission system with unaligned antennas, a new channel model is proposed for performance analysis. Moreover, a purity model of the OAM-MIMO transmission system with unaligned antennas is derived for the non-Kolmogorov turbulence. Furthermore, the error probability and capacity models are derived for OAM-MIMO transmission systems with unaligned antennas. To overcome the disadvantage caused by the unaligned antennas and non-Kolmogorov turbulence, a new optimization algorithm of OAM state interval is proposed to improve the capacity of the OAM-MIMO transmission system. Numerical results indicate that the capacity of OAM-MIMO transmission system is improved by the proposed optimization algorithm. Specifically, the capacity increment of the OAM-MIMO transmission system adopting the proposed optimization algorithm is up to 28.7% and 320.3% when the angle of deflection between the transmitting and receiving antennas is -24 dB and -5 dB, respectively.

No abstract

No abstract