Multirate, two-dimensional channel coding for optical page memories

Abstract

Digital holographic data storage (DHDS) shows promise for next-generation, highly-parallel, random-access, multidimensional data and image storage. Distortion and noise promote detection errors in DHDS systems. Trellis-coded modulation (TCM) combines modulation and error-correction coding to reduce the bit error rate. This paper describes a method of using position-dependent modulation codes with the author's Split TCM architecture for practical TCM in these page memories. Modulation coding with position dependence is shown to provide better resistance to symbol detection errors in high-distortion regions. The architecture provides relative computational efficiency, facilitating high-throughput page access.