Discrete RIS Enhanced Space Shift Keying MIMO System via Reflecting Beamforming Optimization

TL;DR

This paper proposes a discrete RIS-assisted SSK MIMO system optimized via convex approximation techniques to enhance reliability, demonstrating improved performance through simulations considering various system parameters.

Contribution

It introduces a novel optimization method for discrete RIS phase shifts in SSK-MIMO systems to minimize error probability, which is a new approach in this context.

Findings

Optimized RIS phase shifts improve system reliability.

Number of RIS elements affects error performance.

Quantization bits impact the effectiveness of phase control.

Abstract

In this paper, a discrete reconfigurable intelligent surface (RIS)-assisted spatial shift keying (SSK) multiple-input multiple-output (MIMO) scheme is investigated, in which a direct link between the transmitter and the receiver is considered. To improve the reliability of the RIS-SSK-MIMO scheme, we formulate an objective function based on minimizing the average bit error probability (ABEP). Since the reflecting phase shift of RIS is discrete, it is difficult to address this problem directly. To this end, we optimize the RIS phase shift to maximize the Euclidean distance between the minimum constellations by applying the successive convex approximation (SCA) and penaltyalternating optimization method. Simulation results verify the superiority of the proposed RIS-SSK-MIMO scheme and demonstrate the impact of the number of RIS elements, the number of phase quantization bits, and the number of receive and transmit antennas in terms of reliability.