SPYDER: QoS-Aware Radio Resource Allocation in Multiuser ISAC-Capable C-V2X Networks

Integrated Sensing and Communication (ISAC) in cellular vehicle-to-everything (C-V2X) systems presents a promising solution for enhancing road safety and traffic efficiency. However, it also poses significant challenges in radio resource management, particularly in efficiently allocating time-frequency (TF) resources to meet distinct Quality of Service (QoS) requirements, minimizing resource occupancy for high-resolution radar sensing, and mitigating coordination overhead and interference in a multiuser ISACcapable C-V2X network. To overcome these challenges, we propose a novel uncoordinated QoS-aware radio resource allocation (RRA) scheme for a multiuser ISAC-capable C-V2X sidelink system. Unlike existing approaches, the proposed scheme eliminates the need for inter-vehicle coordination, ensuring low spectral requirements while maintaining robust sensing and communication performance in dense, high-mobility environments. Specifically, we extend semi-persistent scheduling (SPS) to enable joint data transmission and radar sensing, dynamically selecting TF resources based on ISAC QoS demands. A key innovation of our approach is the introduction of a sparse random pattern yielding dynamic interleaving (SPYDER) based OFDM grid, which employs non-uniform interleaving of OFDM symbols and subcarriers to support highresolution radar sensing while reducing resource overhead for communication operations. Since SPYDER adopts a non-uniform TF interleaved OFDM grid, it may experience multiuser resource overlapping that could degrade radar detection performance. To counteract this, we employ sparse reconstruction algorithms within the compressed sensing framework, enhancing flexibility in TF resource allocation and providing high-resolution radar sensing despite uncoordinated resource selection. We evaluate the proposed scheme’s performance through numerical simulations and compare it against state-of-the-art methods. The findings highlight the SPYDER grid’s efficiency, robustness to interference, and minimal resource occupancy, making it suitable for next-generation C-V2X networks.