Modulation code optimization for holographic data storage

The performance of page-oriented holographic data storage systems, especially capacity, transmission speed, and symbol error rate, critically depends on the modulation code design. Under the constraint of maintaining approximately 20% code weight, this paper proposes an optimized 5:22 two-dimensional equal-weight sparse modulation code featuring elongated code block geometry. We theoretically evaluated the code rates and decoding efficiencies of various encoding formats with equivalent code weights, demonstrating that this design achieves optimal performance among existing binary encodings. Shape optimization analysis reveals that the elongated code blocks provide enhanced encoding flexibility, enabling the transformation of data pages from conventional square to more efficient circular configurations. Experimental results confirm that the 5:22 coding format achieves a 42.7% storage capacity improvement over the conventional 3:16 coding format while maintaining the raw symbol error rate at 10-4.