Low PMEPR OFDM radar waveform design using the iterative least squares algorithm

TL;DR

This paper introduces an iterative least squares algorithm utilizing tone reservation to effectively reduce PMEPR in OFDM radar waveforms, resulting in smoother envelopes and improved signal quality.

Contribution

It proposes a novel CVE-based optimization method with an iterative algorithm for PMEPR reduction in OFDM radar signals, enhancing waveform stability.

Findings

Significant PMEPR reduction demonstrated in simulations

Envelope fluctuation is effectively minimized

The algorithm guarantees monotonic decrease of the cost function

Abstract

This letter considers waveform design of orthogonal frequency division multiplexing (OFDM) signal for radar applications, and aims at mitigating the envelope fluctuation in OFDM. A novel method is proposed to reduce the peak-to-mean envelope power ratio (PMEPR), which is commonly used to evaluate the fluctuation. The proposed method is based on the tone reservation approach, in which some bits or subcarriers of OFDM are allocated for decreasing PMEPR. We introduce the coefficient of variation of envelopes (CVE) as the cost function for waveform optimization, and develop an iterative least squares algorithm. Minimizing CVE leads to distinct PMEPR reduction, and it is guaranteed that the cost function monotonically decreases by applying the iterative algorithm. Simulations demonstrate that the envelope is significantly smoothed by the proposed method.