Broadband Scanning-Free Rydberg Atomic Communications: Hybrid Noise Modeling and Detector Design

To address the challenges of ultra-long-distance transmission in space-air-ground integrated networks (SAGIN), the Rydberg atomic receiver (RYDAR) has emerged as a promising alternative to classical electric counterparts for communications and sensing, offering unprecedented sensitivity across the entire electromagnetic spectrum. In this paper, we introduce a novel homodyne RYDAR architecture without frequency scanning for instantaneous bandwidth enhancement, and propose a theoretical model for hybrid noise components that incorporates photon shot noise, quantum projection noise, and environmental background noise. The proposed design preserves bit error rate (BER) performance while substantially reducing computational complexity. Simulation results show that the proposed detector achieves up to 2 dB performance gain at a BER of 10^-3 compared with conventional methods, while maintaining low computational complexity under hybrid noise conditions. These results establish an architectural foundation with strong potential for quantum-enhanced wireless reception in future 6G systems.