Symbolized sequence embedding for arbitrary-order QAM schemes in photonics-aided fiber wireless seamless integrated transmission system

This paper proposes a scheme of symbolized sequence embedding for arbitrary-order quadrature amplitude modulation (QAM) schemes in photonics-aided fiber wireless seamless integrated transmission system, breaking the rigid constraint of traditional modulation schemes requiring power-of-two orders. This enables continuous fine-tuning of information entropy. The scheme dynamically filters serialized coordinate points in three-dimensional constellation space, optimizes the minimum euclidean distance (MED) using an annealing algorithm to enhance noise immunity, and designs an entropy-adaptive mapping mechanism for precise adaptation to target entropy values. Experimental results demonstrate that in a W-band coherent optical communication system employing photonically-assisted heterodyne reception, the proposed 5QAM scheme achieves improved receiver sensitivity compared to the traditional huffman coding scheme. Specifically, gains of 0.2 dB, 0.4 dB, and 0.6 dB are observed at entropy values of 2, 1.67, and 1.33, respectively. The scheme is compatible with multi-order modulation signals such as 6QAM and 16QAM, demonstrating its versatility. It provides a scalable physical-layer solution for ultra-flexible rate scenarios in 6G. Its low-complexity architecture and multi-order modulation compatibility highlight its significant application potential in terahertz communications and fiber-wireless convergence networks.