PAPR-optimized OFDM Design for Opportunistic Communications and Sensing

TL;DR

This paper introduces a novel PAPR reduction method for OFDM systems that optimizes tone reservation, enabling opportunistic use of reserved tones for additional functionalities like sensing and cognitive radio.

Contribution

It proposes a new TR optimization approach using l0 norm regularization and fractional programming to minimize reserved tones while maintaining PAPR constraints, facilitating integration of multiple functionalities.

Findings

Achieves PAPR reduction with fewer reserved tones than existing methods.

Ensures high probability of meeting PAPR targets.

Enables opportunistic use of reserved tones for additional system functionalities.

Abstract

We consider the problem of peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems via optimized sparsification of tone reservation (TR). In particular, we propose a novel TR optimization method in which the minimum number of effectively used peak-reserved tones (PRTs) required to satisfy a prescribed PAPR level is found, leaving the remaining PRTs free to be opportunistically utilized by other functionalities, such as joint communication and sensing (JCAS), index modulation (IM), cognitive radio (CR) and others. The proposed method relies on an l0 norm regularization approach to penalize the number of PRTs, leading to a problem convexized via fractional programming (FP), whose solution is shown to ensure that the prescribed PAPR is achieved with high probability with a smaller number of PRTs than state of the art (SotA) methods. The contribution can be seen as a mechanism to enable the opportunistic integration of adjacent functionalities into existing OFDM-based systems.