Abstract:Orbital angular momentum (OAM) is a technique that provides an additional degree of freedom to enhance the spectral efficiency of wireless communications. However, when applying OAM to wireless communication, the orthogonality between modes can only be utilized if the transmitting and receiving antennas are perfectly aligned. This paper combines the OAM multiplexing generated by uniform circular array (UCA) antennas with multiple-input multiple-output (MIMO) technology to form a uniform concentric circular array orbital angular momentum (UCCA-OAM) communication system. To address the modal interference caused by misalignment of the transmitting and receiving UCA antennas and the array interference between concentric circular arrays in the MIMO system, a dual-module interference cancellation scheme based on progressive block matrix inversion is proposed. Experimental results demonstrate that the proposed dual-module interference cancellation scheme effectively suppresses both modal and array interference, thereby improving the communication performance of the UCCA-OAM system.