Multi-Target Flexible Angular Emulation for ISAC Base Station Testing Using a Conductive Amplitude and Phase Matrix Setup: Framework and Experimental Validation

Abstract

Comprehensive evaluation of the functionalities, algorithms, hardware components, and performance characteristics of future integrated sensing and communication (ISAC) base stations (BSs) under realistic deployment scenarios in controlled laboratory environments represents a critical requirement for ISAC technology advancement. A primary challenge in achieving this objective involves the emulation of multiple targets with arbitrary radar cross-section (RCS), range, angle, and Doppler profiles for ISAC BS equipped with large-scale antenna arrays using radar target simulator (RTS) with limited interface ports. In this work, we introduce a simple yet highly effective and practical conductive amplitude and phase matrix framework to address this fundamental challenge. The core concept involves introducing a tunable conductive amplitude and phase modulation network in the test configuration between the ISAC BS under test and a RTS. Based on this structure, we subsequently investigate the corresponding configurations for different sensing operational modes of ISAC BSs, specifically the array duplex transmission and reception (ADTR) mode and the split-array transmission and reception (SATR) mode. For experimental validation, we design two distinct monostatic sensing scenarios to demonstrate the framework capabilities across both operational modes. The first scenario involves dynamic multi-drone sensing validation for ADTR mode operation, while the second scenario addresses static single-drone sensing for SATR mode validation. The experimental results demonstrate that the proposed framework can accurately emulate the joint RCS, range, velocity, and angular characteristics of multiple sensing targets within the conductive test environment, highlighting its significant potential for testing applications in sub-6 GHz ISAC BS development and validation.

Figures (10)

• Figure 1: Diagram of the proposed sensing targets emulation framework for ISAC BS conducted testing, where $K$ represents the number of antenna ports and $N$ denotes the number of emulated targets. Note that for typical ISAC BS testing scenarios, the condition $K \gg N$ holds.
• Figure 2: ISAC BS multi-target sensing scenario in ADTR mode and the proposed emulation configuration for this scenario. (a) Illustration of the sensing scenario. (b) Diagram of the emulation configuration. Note that in (b), only the schematic related to the $n$-th target emulation is shown for clarity.
• Figure 3: ISAC BS multi-target sensing scenario in SATR mode and the proposed emulation configuration for this scenario. (a) Illustration of the sensing scenario. (b) Diagram of the emulation configuration. Note that in (b), only the schematic related to the $n$-th target emulation is shown for clarity.
• Figure 4: Target sensing scenario and coordinate system configuration. We define the ISAC BS array center as the origin, with the vertical array plane facing the positive $y$-axis, and the $z$-axis pointing upward. The positive direction of the azimuth angle $\phi$ increases along the positive $x$-axis from the positive $y$-axis. The elevation angle $\theta$ increases in the direction of the positive $z$-axis from the $xoy$-plane.
• Figure 5: Experiment setup of the sensing targets emulation for the ADTR mode of the ISAC BS. (a) Illustration of the measurement setup. (b) Photo of the setup in the laboratory condition.