Vehicular Multistatic OTFS-ISAC: A Geometry-Aware Deployment and Kalman-Based Tracking
Jyotsna Rani, Kuntal Deka, Ganesh Prasad, Zilong Liu
TL;DR
This work addresses the challenge of robust joint sensing and communication in high-m mobility vehicular networks by proposing a geometry-aware multistatic OTFS-ISAC framework. It develops a triangulation-based cooperative sensing approach, derives closed-form localization-error covariances, and shows that maximizing triangulation area minimizes estimation error, with orthogonal-axis deployments achieving near-optimal cubic reductions when employing $N_a$ independent antennas. The paper also integrates a correlated random walk (CRW) based Kalman filter to enhance tracking and introduces sensing-aided channel reconstruction for reliable DD-domain sensing and communication. Numerical results demonstrate substantial localization RMSE and BER improvements, confirming the benefits of geometry-aware deployment and KF-assisted tracking for dynamic vehicular ISAC. The proposed framework thus offers a principled design and practical validation for high-mobility ISAC systems in distributed vehicular networks.
Abstract
Integrated sensing and communication (ISAC) is a promising paradigm for next-generation vehicular networks, yet existing orthogonal frequency-division multiplexing (OFDM)-based designs suffer from limited spatial diversity and severe sensitivity to Doppler and multipath effects. While orthogonal time-frequency space (OTFS) modulation offers robustness under high mobility, the impact of spatial node deployment in multistatic OTFS-ISAC has remained largely unexplored. This paper presents the first geometry-aware multistatic OTFS-ISAC framework, in which a triangulation-based cooperative sensing approach is developed for joint target localization and velocity estimation. Closed-form expressions for the localization error covariance are derived under general receiver topologies, revealing that maximizing the triangulation area is fundamental to minimizing estimation error. This leads to a near-optimal deployment strategy based on orthogonal receiver placement and its equivalence to multi-antenna architectures with cubic-order error reduction. To enable reliable tracking of moving targets, a correlated random walk (CRW)-based Kalman filter (KF) framework is integrated into multistatic OTFS-ISAC for active sensing and ISAC. Numerical results demonstrate significant reductions in localization root-mean-square error (RMSE) and communication bit error rate (BER), highlighting the effectiveness of geometry-aware, KF-assisted multistatic OTFS-ISAC in dynamic vehicular environments.
