OFDM with Index Modulation in Orbital Angular Momentum Multiplexed Free\n Space Optical Links

Communication using orbital angular momentum (OAM) modes has recently\nreceived a considerable interest in free space optical (FSO) communications.\nPropagating OAM modes through free space may be subject to atmospheric\nturbulence (AT) distortions that cause signal attenuation and crosstalk which\ndegrades the system capacity and increases the error probability. In this\npaper, we propose to enhance the OAM FSO communications in terms of bit error\nrate and spectral efficiency, for different levels of AT regimes. The\nperformance gain is achieved by introducing orthogonal frequency division\nmultiplexing (OFDM) with index modulation technique to the OAM FSO system.\n