Robust Beamforming Design for OTFS-NOMA

TL;DR

This paper proposes robust beamforming strategies for OTFS-NOMA networks to enhance low-mobility users' data rates while ensuring high-mobility users' quality of service, considering channel uncertainties.

Contribution

It introduces a novel beamforming design framework for OTFS-NOMA that accounts for channel errors and provides low-complexity solutions for practical implementation.

Findings

Proposed beamforming schemes outperform random beamforming in simulations.

The methods effectively handle channel state information errors.

Significant performance gains are demonstrated through simulations.

Abstract

This paper considers the design of beamforming for orthogonal time frequency space modulation assisted non-orthogonal multiple access (OTFS-NOMA) networks, in which a high-mobility user is sharing the spectrum with multiple low-mobility NOMA users. In particular, the beamforming design is formulated as an optimization problem whose objective is to maximize the low-mobility NOMA users' data rates while guaranteeing that the high-mobility user's targeted data rate can be met. Both the cases with and without channel state information errors are considered, where low-complexity solutions are developed by applying successive convex approximation and semidefinite relaxation. Simulation results are also provided to show that the use of the proposed beamforming schemes can yield a significant performance gain over random beamforming.