Doppler Robust Vortex Wavefront Design for Integrated Sensing and Communication

TL;DR

This paper introduces a Doppler-robust integrated sensing and communication framework that enhances sensing accuracy and spectral efficiency in dynamic environments by jointly estimating target parameters and optimizing beamforming.

Contribution

It proposes a novel Doppler-robust ISAC framework with a VCM-EM algorithm for joint target parameter estimation and beamforming optimization in dynamic scenes.

Findings

Higher sensing accuracy compared to baseline schemes

Improved spectral efficiency in dynamic scenarios

Effective Doppler compensation in vortex wavefront design

Abstract

Integrated sensing and communication (ISAC) is a promising paradigm for future wireless systems due to spectrum reuse, hardware sharing, and joint waveform design. In dynamic scenes, Doppler shifts degrade both sensing and communication, which is particularly critical for beam-sensitive orbital angular momentum (OAM) wavefronts. To address this, we propose a Doppler-robust ISAC framework, which first senses and then communicates. Specifically, in the sensing phase, multiple vortex modes are simultaneously transmitted via code-division mode-multiplexing (CDMM). To solve Doppler-induced inter-mode interference, we propose a velocity-consistency matching (VCM)-expectation maximization (EM) algorithm that jointly decodes the sensing matrix and estimates range, azimuth, elevation, and velocity for multiple moving targets. In the communication phase, the joint transmitter (Tx) beamforming and receiver (Rx) beam steering are configured from the estimated channel state information (CSI). We further quantify the sensing-communication allocation trade-off by evaluating how pilot length affects estimation accuracy, beam alignment, and spectral efficiency (SE). Simulation results show that the proposed VCM-EM and ISAC designs achieve higher sensing accuracy and communication SE than baseline schemes in dynamic scenarios.