Codeword Design of a Rate-5/6 for Single-Reader Two-Track Reading in BPMR Systems

Abstract

At present, the information storage demand of hard disk drive (HDD) was dramatically increasing every year. However, an increase of an areal density (AD) for bit-patterned media recording (BPMR) seems to be crucial for HDD industry. One of the main problems of BPMR system is two-dimensional interference effect that composes of inter-track interference (ITI) and inter-symbol interference (ISI), which still be the main challenge that we have to flounder to continuously enhance the efficiency of magnetic recording system. Therefore, this paper proposes a rate-5/6 2D modulation code to evolve bit error rate (BER) efficiency of a staggered single-reader two-track reading (SRTR) based BPMR systems. We select all 32 codewords from all 64 considered patterns according to the statistics principle considering. The first 32 patterns that provide the least error-bit number will then be defined as our proposed codewords. These selected patterns can efficiently avoid the forbidden patterns that means it is going to radically suppress both ISI and ITI effects. We simply encode by using a look-up table, while we use the Euclidean distance concept to recover user bits in the decoding process. From the simulation, we found that the proposed method shows a better BER efficiency than both the uncoded and conventional recording systems. Even we add more media noises, this proposed system still provides us with a better performance. Moreover, SRTR scheme offers us more satisfactory capability than the conventional recording systems.