An Approach for Reconfigurable Intelligent Surface (RIS) design for
MIMO-NOMA Transmission: theoretical study
Abstract
The approach (Paradigm) presented hereafter was inspired by two basic
ideas: assuming the MIMO-RIS-NOMA communication channel as a dispersive
channel with fading and representing the later by means of Generalized
Kroneker Channel model (GKCM) applying the so-called “Orthogonalization
Approach” based on the utilization of the “universal” eigenbasis in
the form of Prolate Spheroidal Wave Functions (PSWF). In other words,
the essence of the approach lies in representing the MIMO-RIS-NOMA
channel by means of the finite set of artificially created orthogonal
trajectories for wave propagation (PSWF eigenbasis) depending to the
Planar Antenna(PA) patterns at the Transmitting and Receiving terminals
of MIMO systems, being connected between themselves by the so-called
Coupling Matrix (CM) of the RIS. Certainly, the goal for RIS (by certain
choice of the elements of CM) is to provide the system for the decoding
of the NOMA users with the required values of SNR for each user to
guarantee its successful decoding processing. Theoretical analysis of
this paradigm is presented in the following material.