Flexible Intelligent Metasurfaces in High-Mobility MIMO Integrated Sensing and Communications

TL;DR

This paper introduces a new channel model with flexible intelligent metasurfaces for high-mobility MIMO systems, optimizing integrated sensing and communications performance across various waveforms.

Contribution

It proposes a novel FIM-parameterized DD channel model and demonstrates its application in maximizing achievable rates with sensing constraints in high-mobility scenarios.

Findings

FIM technology significantly impacts achievable rate performance.

Careful parameterization is crucial for effective ISAC performance.

The gradient ascent algorithm effectively solves the rate maximization problem.

Abstract

We propose a novel doubly-dispersive (DD) multiple-input multiple-output (MIMO) channel model incorporating flexible intelligent metasurfaces (FIMs), which is suitable for integrated sensing and communications (ISAC) in high-mobility scenarios. We then discuss how the proposed FIM-parameterized DD (FPDD) channel model can be applied in a logical manner to ISAC waveforms that are known to perform well in DD environments, namely, orthogonal frequency division multiplexing (OFDM), orthogonal time frequency space (OTFS), and affine frequency division multiplexing (AFDM). Leveraging the proposed model, we formulate an achievable rate maximization problem with a strong sensing constraint for all the aforementioned waveforms, which we then solve via a gradient ascent algorithm with closed-form gradients presented as a bonus. Our numerical results indicate that the achievable rate is significantly impacted by the emerging FIM technology with careful parametrization essential in obtaining strong ISAC performance across all waveforms suitable to mitigating the effects of DD channels.