Resilient non-line-of-sight optical camera communication using byte-level RaptorQ and normalized variance ratio

In this Letter, we propose a resilient non-line-of-sight (NLOS) optical camera communication (OCC) system addressing the critical challenges of stochastic data loss and spatial division multiplexing (SDM). It integrates two core innovations: a unified byte-level RaptorQ coding scheme that reconstructs source blocks from fragmented data, obviating the need for repetitive transmissions and increasing throughput by 49% for a data reception ratio (DRR) of 0.82 and a 4-byte payload; and the normalized variance ratio (NVR), a novel, to the best of our knowledge, statistical metric that enables NLOS SDM by adaptively identifying distinct data streams within partially superimposed light patterns. Experimental validation demonstrates the system's resilience: at 0.8 m, our NVR-enabled NLOS SDM 2-LED system delivers 4.4 kbps throughput while maintaining a bit error rate (BER) below 10^-5. This result offers a substantial reliability advantage over other OCC systems such as ReflexCode, showcasing the system's potential for practical applications.