An Open-Source SDR-Based Device-Free Sensing Platform for Integrated Sensing and Communication (ISAC)
Hanae Otani, T. Murakami, Kazuya Ohara, Shinya Otsuki, Yasushi Takatori, Tomoaki Ogawa · IEEE Open Journal of the Communications Society · 2025
Integrated Sensing and Communication (ISAC) is a key use case in International Mobile Telecommunications (IMT)-2030, as defined by the International Telecommunication Union-Radiocommunication Sector (ITU-R). It enhances value-added communication systems by integrating sensing applications with communication infrastructure. Numerous ISAC use cases have been explored within the 3rd Generation Partnership Project (3GPP), ranging from intruder and drone detection to precipitation estimation. However, the trade-off between communication and sensing systems poses significant challenges when constructing an ISAC framework, and demonstrations of ISAC systems remain limited. In this paper, we propose an open-source software-defined radio (SDR) device-free sensing platform that leverages an open database to identify available frequencies in the target sensing area. The platform selects frequencies for sensing based on the measured channel state information (CSI) and utilizes them for analysis. This approach employs the broadcast signal from the base station, ensuring no interference with the communication systems efficiency. Furthermore, it can be implemented at a low cost by utilizing OpenAirInterface (OAI) as an open-source software (OSS) platform for capturing cellular signals. We demonstrate the feasibility of this platform by applying it to real-world equipment in an outdoor human detection scenario. Our findings show that analyzing signals selected from multiple frequency bands using the proposed system can reduce data size while maintaining or improving sensing accuracy. This approach offers the potential for performance improvement or reduced degradation of the accuracy of wireless sensing.