Drone Surveillance via Coordinated Beam Sweeping in MIMO-ISAC Networks

TL;DR

This work addresses drone detection within 5G NR by integrating sensing with the SSB cell-search procedure through a MIMO-ISAC, multistatic framework. A dedicated sensing signal is coordinated with SSB beams to illuminate a 3D voxel grid while suppressing interference via orthogonality constraints, and a semidefinite-relaxation-based precoder design yields near-optimal sensing performance under UE SINR and direct-link masking constraints. The proposed approach outperforms non-coordinated precoding by roughly $20$ dB in average sensing SINR and remains robust to drone altitude changes, with detection performance achieving high $P_d$ at practical power levels. These results suggest a viable, scalable method for real-time drone surveillance integrated into existing cellular infrastructures, enabling improved situational awareness in airspace security.

Abstract

This paper introduces a scheme for drone surveillance coordinated with the fifth generation (5G) synchronization signal block (SSB) cell-search procedure to simultaneously detect low-altitude drones within a volumetric surveillance grid. Herein, we consider a multistatic configuration where multiple access points (APs) collaboratively illuminate the volume while independently transmitting SSB broadcast signals. Both tasks are performed through a beam sweeping. In the proposed scheme, coordinated APs send sensing beams toward a grid of voxels within the volumetric surveillance region simultaneously with the 5G SSB burst. To prevent interference between communication and sensing signals, we propose a precoder design that guarantees orthogonality of the sensing beam and the SSB in order to maximize the sensing signal-to-interference-plus-noise ratio (SINR) while ensuring a specified SINR for users, as well as minimizing the impact of the direct link. The results demonstrate that the proposed precoder outperforms the non-coordinated precoder and is minimally affected by variations in drone altitude.

Figures (7)

• Figure 1: Multistatic setup in a hexagonal grid.
• Figure 2: TDD flow with sensing reception with $R$$=$$Q$.
• Figure 3: Departure and arrival angles for the sensing channel of voxel index $q$.
• Figure 4: Sensing SINR.
• Figure 5: Empirical CDF of $\gamma_\text{sen}$.