Error Correcting 4/6 Modulation Codes for Holographic Data Storage

Abstract

We introduce error correcting 4/6 modulation codes for holographic data storage. Above all, the merit of the proposed modulation codes is that their trellis structure allows error correcting capability. The proposed codes also do not have any fatal (i.e., isolated pixels) two-dimensional intersymbol interference (2D ISI) patterns. The decoding scheme uses the Viterbi algorithm. As a result, the proposed codes have better performance than the conventional 6/8 and 4/6 modulation codes overall. #

2/3 Modulation Code and Its Vterbi Decoder for 4-level Holographic Data Storage

“…하 지만 M 레벨로 저장될 경우, 블러 효과가 심해져 시스템의 성능이 홀로그래픽 데이터 저장장치의 경 우보다 저하될 수 있다. 이와 같은 인접 신호간 간 섭을 완화시키기 위하여 다양한 2차원 변조 부호가 연구되고 있다 [8][9][10][11][12][13] . Table 1.…”

Error-Correcting 7/9 Modulation Codes For Holographic Data Storage

“…To solve these problems, two-dimensional modulation codes are usually applied [5][6][7][8][9][10][11][12] . One scheme removes the isolated ON or OFF pixel patterns that are the main source of the ISI problem [5][6] , resulting in a better performance of the modulation code by removing the isolated patterns.…”

“…Burr et al proposed an 8:12 code to improve robustness against noise; this is considered an error-correcting code because the minimum Hamming distance of the code is greater than 3 [8][9][10][11] .…”

“…Kim and Lee introduced a trellis modulation structure for error-correction capability [10] . They assigned appropriate codewords to each branch by selecting codewords with a minimum Hamming distance greater than or equal to 2; the trellis modulation then increases the distance of the shortest error event, which creates the error-correction capability.…”

“…error-correcting modulation code that has a higher code rate and error-correcting capability compared with prior modulation codes [9][10][11] . In Section 2, we introduce codewords of a 7/9 error-correcting modulation code for an HDS system.…”