| With the development of the information technology, people require large capacity of storage medium for recording information.For its high storage capacity,rapid access and data transfer rates,holographic storage technology is being researched broadly.Coding techniques play an important role in holographic data storage(HDS) systems.In this thesis,we will study the two-dimentional interleaving techniques and error-correcting codes in HDS systems.For interleaving schemes,we carefully investigated three two-dimensional interleaving schemes and their application in the HDS systems,two of them are lattice interleaving schemes: A(t,1) and A(t,2),one is cyclic shifting interleaving schemes.The optimal constructions of interleaving techniques are presented and simulated in HDS systems.Simulation results show that the three interleaving schemes can defend two-dimentional burst errors effectively .In addition,we compared the simulation results of lattice interleaving schemes with that of the cyclic shifting interleaving schemes.We show that the cyclic shifting interleaving schemes have better burst error correcting power than lattice interleaving schemes.For error-correcting codes,the information is recorded in the form of two-dimensional data pages in HDS systems,and BER increases with moving from the center to the corner of the page,so the recorded information bits should nonuniformly be protected. Because the RS codes that was conventionally employed in HDS systems cannot correct the nonuniform errors,in this thesis we considered the RA codes that perform near the Shannon limit as error-correction codes in HDS systems.RA codes have linear encoding and decoding algorithms,using maximum likelihood decoding ,at rates arbitrarily close to channel capacity.According to the noise pattern in HDS systems,we designed IRA codes by Gaussian approximation methods and simulated it in HDS systems .The results show that carefully designed IRA codes are potentially suitable for the HDS systems. |
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