Divergence intensity and mode combinations for multiple orbital angular momentum transmission

Abstract

In this paper, we propose divergence intensity (DI) and mode combinations for multiple orbital angular momentum (OAM) users to enhance the sum capacity. Generally, OAM multiplexing has beam divergence (BD) limiting the achievable link distance and degrading performance. The effective OAM channel model implies DI which is considered as intensity of OAM mode. In addition, the near-far mode combination is recommended to be sub-optimal compared with different mode combinations which types are sequential and uniform. The sub-optimal mode combination outperforms the other two mode combinations because channel gain shares the DI effect. The performance of the proposed scheme is derived and simulated in terms of normalized DI, capacity per user, and sum capacity. (c) 2023 The Authors. Published by Elsevier B.V. on behalf of The Korean Institute of Communications and Information Sciences. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).