Blind decision feedback equalizer for holographic versatile disc

As the amount of data increases, holographic data storage (HDS) is considered as a next generation storage medium. Since HDS uses two-dimensional (2D) data, it causes intersymbol interference (ISI) between adjacent pixels not only in the horizontal direction but also in the vertical direction. Thus, studies have been carried out to reduce such 2D ISI, and especially many researches using the partial response maximum likelihood (PRML) method have been carried out. These PRML methods have good bit-error-rate (BER) performance, but also have various disadvantages. Therefore, we propose a simple blind decision feedback equalizer (blind DFE) that does not use soft output Viterbi algorithm (SOVA) for application to European standard holographic versatile disc (HVD). First, we propose a blind equalizer using simle theshold method to get information that the equalizer can refer to. In order to make it work well in any environment, the threshold value is adaptively determined using the statistical characteristics of the received image. And, in order to reduce errors due to the data that cannot be distinguished only by the blind equalizer, we add a decision feedback loop after the blind equalizer. Finally, various simulations were conducted to confirm the performance of blind DFE for HVD.