Multi-carrier based positional modulation design with discrete phase values for metasurface elements

Positional modulation (PM) as an extension of directional modulation (DM) can transmit information to the desired position(s) with known constellation mappings, but with scrambled ones in other areas. In this paper, a multi-carrier based PM design is proposed with practical discrete phase values for the employed reconfigurable metasurface, where multiple signals can be transmitted to the desired position(s) at multiple frequencies over a single channel simultaneously, and the traditional narrowband single-carrier transmission can be considered as a special case. Design examples for both the single-carrier and multi-carrier cases are provided to show the effectiveness of the proposed design.