Achieving Practical OAM Based Wireless Communications With Misaligned Transceiver

TL;DR

This paper proposes a joint beamforming and pre-detection scheme to enable practical orbital angular momentum (OAM) wireless communications with misaligned transceivers, maintaining mode orthogonality and improving spectrum efficiency.

Contribution

It introduces a novel BePre scheme that converts the channel matrix into a circulant form, allowing effective detection of multiple OAM modes despite transceiver misalignment.

Findings

The BePre scheme maintains OAM mode orthogonality under misalignment.

Simulation results show improved signal detection for multiple OAM modes.

The approach significantly enhances spectrum efficiency in practical scenarios.

Abstract

Orbital angular momentum (OAM) has attracted much attention for radio vortex wireless communications due to the orthogonality among different OAM-modes. To maintain the orthogonality among different OAM modes at the receiver, the strict alignment between transmit and receive antennas is highly demanded. However, it is not practical to guarantee the transceiver alignment in wireless communications. The phase turbulence, resulting from the misaligned transceivers, leads to serious inter-mode interference among different OAM modes and therefore fail for signals detection of multiple OAM modes at the receiver. To achieve practical OAM based wireless communications, in this paper we investigate the radio vortex wireless communications with misaligned transmit and receive antennas. We propose a joint Beamforming and Pre-detection (BePre) scheme, which uses two unitary matrices to convert the channel matrix into the equivalent circulant matrix for keeping the orthogonality among OAM-modes at the receiver. Then, the OAM signals can be detected with the mode-decomposition scheme at the misaligned receiver. Extensive simulations obtained validate and evaluate that our developed joint BePre scheme can efficiently detect the signals of multiple OAM-modes for the misaligned transceiver and can significantly increase the spectrum efficiency.