Localization in ISAC: A Review

Integrated sensing and communication (ISAC) has emerged as a key component of modern communication technologies that are driven by rapid advancements in Wireless Sensor Networks (WSNs). The increasing adoption of the Internet of Things (IoT) and the Industrial Internet of Things (IIoT) is transforming various walks of life by enabling a diverse range of functional applications. As automation and connectivity continues to evolve, ISAC plays a crucial role in ensuring seamless communication and real time data sensing, establishing itself as a fundamental pillar of contemporary technological ecosystems. Notably, ISAC offers several advantages over systems that rely on separate transceivers and receivers, including reduced costs, enhanced spectral efficiency, and improved energy efficiency. This review article provides a comprehensive overview of the core radar topologies employed in ISAC communication systems and examines the corresponding localization algorithms that align with these specific radar configurations. Furthermore, the study analyzes key parameters that can directly influence the performance of the localization estimation process within ISAC systems. Once a communication system is deployed, an important consideration is its energy consumption. To address this, the review highlights the relationship between energy usage and the types of antennas employed. Furthermore, we examine the emerging trends and techniques in ISAC systems, focusing on their role in optimizing and enhancing various communication applications such as channel estimation etc. We conclude the article by outlining limitations and some open challenges for future research directions in the localization of nodes in ISAC systems, providing insights into potential advancements.