A Review of 6G Radio Signal Recognition Based on Digital Signal Processing

As a vital step before signal demodulation, radio signal recognition (RSR) technology must overcome ultra-high dimensionality, ultra-wide bandwidth, extreme heterogeneity, and strong dynamicity due to the rapid development of 6G research and its core enabling technologie. Radio signal recognition underpins the core capabilities of 6G, enabling intelligent spectrum situational awareness, dynamic resource allocation, precise identification of non-cooperative targets, and ultra-secure communications. As a result, the performance requirements for RSR have also rapidly increased. Digital signal processing (DSP) is the essential core and primary component of RSR technology, playing a vital role in radio signal recognition. Therefore, this paper focuses on RSR technology based on digital signal processing, combining recent research findings to systematically review its progress, challenges, and future directions. This study finds that in the 6G era, RSR can break the bottleneck of security, hardware and cross-domain conflict through three paths: "quantum-DSP collaborative computing, hypersurface photon sensing and federated learning".