Multidimensional coded modulation for wireless communications beyond 5G

In this keynote invited paper, to address key challenges for beyond 5G wireless technologies in a simultaneous manner, we propose an orbital angular momentum (OAM) based, energy-efficient multidimensional coded modulation. The key idea is to employ all available degrees of freedom (DOFs) to convey the information over the wireless links including amplitude, phase, polarization state, and spatial-domain DOFs. In particular, the OAM is associated with azimuthal phase dependence of the wavefront, and represents an underutilized DOF. Given that OAM eigenstates are orthogonal, an arbitrary number of bits per symbol can be transmitted. To implement OAM multiplexer and demultiplexer in the RF domain, we propose to use a properly designed antenna arrays. Monte Carlo simulations demonstrate high tolerance to fading effects of LDPC-coded multidimensional signaling schemes compared to conventional LDPC-coded QAM.