Time-Modulated EM Skins for Integrated Sensing and Communications

TL;DR

This paper introduces time-modulated electromagnetic skins that generate harmonic beams for integrated sensing and communication, enabling simultaneous user localization and data transmission in smart environments.

Contribution

The work presents a novel method using TM-EMS to achieve integrated sensing and communication through harmonic beam control and an evolutionary optimization approach.

Findings

Numerical and experimental tests confirm the effectiveness of the proposed method.

Harmonic beam control enables accurate user localization and communication.

The evolutionary approach successfully determines optimal TM-EMS modulation sequences.

Abstract

An innovative solution, based on the exploitation of the harmonic beams generated by time-modulated electromagnetic skins (TM-EMSs), is proposed for the implementation of integrated sensing and communication (ISAC) functionalities in a Smart Electromagnetic Environment (SEME) scenario. More in detail, the field radiated by a user terminal, located at an unknown position, is assumed to illuminate a passive TM-EMS that, thanks to a suitable modulation of the local reflection coefficients at the meta-atom level of the EMS surface, simultaneously reflects towards a receiving base station (BS) a "sum" beam and a "difference" one at slightly different frequencies. By processing the received signals and exploiting monopulse radar tracking concepts, the BS both localizes the user terminal and, as a by-product, establishes a communication link with it by leveraging on the "sum" reflected beam. Towards this purpose, the arising harmonic beam control problem is reformulated as a global optimization one, which is successively solved by means of an evolutionary iterative approach to determine the desired TM-EMS modulation sequence. The results from selected numerical and experimental tests are reported to assess the effectiveness and the reliability of the proposed approach.