A Framework for Uplink ISAC Receiver Designs: Performance Analysis and Algorithm Development

2025-03-04

AI Summary

In uplink integrated sensing and communication (ISAC) systems, jointly optimizing communication signal detection and target response estimation remains challenging. To address this, this paper proposes a flexible projection (FP)-based receiver framework that unifies projection-based and successive interference cancellation (SIC) paradigms for the first time. We introduce three novel architectures: dynamic FP (DFP), parallel DFP (PDFP), and block-structured receivers, and establish a pairwise error probability (PEP)-based performance analysis model. A homotopy-based optimization algorithm is further developed to enable adaptive, dynamic tuning of the trade-off factor. Theoretical analysis reveals that the optimal trade-off factor depends on both the detection algorithm type and the sensing-to-communication power ratio. Simulation results demonstrate that DFP and PDFP significantly improve SINR and target response estimation accuracy, while enhancing environmental adaptability under dynamic channel conditions.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Uplink integrated sensing and communication (ISAC) systems have recently emerged as a promising research direction, enabling simultaneous uplink signal detection and target sensing. In this paper, we propose flexible projection (FP)-type receivers that unify the projection-type receivers and the successive interference cancellation (SIC)-type receivers by using a flexible tradeoff factor to adapt to dynamically changing uplink ISAC scenarios. The FP-type receivers address the joint signal detection and target response estimation problem through two coordinated phases: 1) Communication signal detection using a reconstructed signal whose composition is controlled by the tradeoff factor, followed by 2) Target response estimation performed through subtraction of the detected communication signal from the received signal. With adjustable tradeoff factors, the FP-type receivers can balance the enhancement of the signal-to-interference-plus-noise ratio (SINR) with the reduction of correlation in the reconstructed signal for communication signal detection. The pairwise error probabilities (PEPs) are analyzed for both maximum likelihood (ML) and zero-forcing (ZF) detectors, revealing that the optimal tradeoff factor should be determined based on the adopted detection algorithm and the relative power of the sensing and communication (S&C) signal. A homotopy optimization framework is first applied for the FP-type receivers with a fixed trade-off factor. This framework is then extended to develop dynamic FP (DFP)-type receivers, which iteratively adjust the trade-off factor for improved algorithm performance and environmental adaptability. Subsequently, two extensions are explored to further enhance the receivers' performance: parallel DFP (PDFP)-type receivers and a block-structured receiver design. Finally, the effectiveness of the proposed receiver designs is verified via simulations.

Problem

• Develop flexible projection-type receivers for uplink ISAC systems.
• Balance signal detection and target response estimation dynamically.
• Optimize tradeoff factors for enhanced SINR and reduced correlation.

Innovation

• Flexible projection-type receivers unify projection and SIC.
• Dynamic FP-type receivers adjust trade-off factors iteratively.
• Parallel DFP-type receivers enhance performance and adaptability.