Input Distribution Design for Ranging-Oriented OFDM-ISAC Systems Under Frequency-Selective Fading

TL;DR

This paper proposes an efficient input distribution design method for OFDM-ISAC systems in 6G, balancing communication and sensing by resourcefully managing constellation kurtosis across subcarriers.

Contribution

It introduces a novel, computationally efficient approach for constellation design in OFDM-ISAC systems considering practical sensing constraints.

Findings

Optimal constellation kurtosis can be treated as a resource for sensing performance.

The proposed method effectively balances communication rate and sensing accuracy.

The approach is computationally efficient and suitable for frequency-selective channels.

Abstract

The implementation of the \ac{isac} feature in \ac{6g} networks is most likely to be based on the framework of \ac{ofdm}. Input distribution design, or constellation design, is a crucial technique in \ac{ofdm}-\ac{isac} systems enabling a favorable balance between communication rate and sensing performance. In this treatise, we propose a computationally efficient input distribution design approach for \ac{ofdm}-\ac{isac} under frequency-selective channels, following the theoretical framework of capacity distortion. We highlight that under practical sensing constraints, the optimal strategy is to treat the kurtosis of constellations as a resource, and allocate it appropriately over subcarriers.