Hardware Impairments in ISAC Systems: A Comprehensive Survey

Abstract

Integrated sensing and communication (ISAC) systems are instrumental in shaping the future of 6G by enabling the dual functions. In addition, the emergence of smart electromagnetic (EM) environments based on a heterogeneous deployment of EM entities further strengthens the ISAC paradigm by enabling fine-grained control and adaptation of wireless propagation conditions. However, the performance of this paradigm is significantly hindered by hardware impairments (HWIs), especially those arising from non-ideal radio-frequency components. In this paper, we provide a comprehensive overview of HWIs in transceivers and EM entities within ISAC systems. Specifically, we systematically identify and categorize various impairments, offering a detailed analysis of their sources, impact mechanisms, and commonly used models for characterization. We further compare their effects on communication and sensing performance, highlighting the similarities, differences, and resulting trade-offs between the two functions. Furthermore, we comprehensively review existing signal-processing-based compensation and utilization approaches for representative HWIs and compare their practical strengths and limitations. Beyond the technical review, we examine relevant standardization and industry activities and provide practical design guidelines for HWI-aware ISAC systems. Finally, we discuss open challenges and emerging opportunities in addressing HWIs for ISAC systems, providing a roadmap for future research. This work offers a valuable foundation for developing next-generation ISAC systems capable of overcoming HWI-induced performance limitations and supporting robust practical deployment.