ERROR CORRECTION DEVICE FOR OPTICAL MEMORY OF MASS APPLICATION

Abstract

Currently one of the most commonly used carriers of digital information is optical multi-purpose DVD discs. At the same time these carriers have a significant disadvantage, namely, a tendency to a relatively large number of errors in the reading of information due to damage of the recording layer during production or operation. The article presents the structural and functional organization of the error correction device for optical mass storage (optical DVDs) that implements the iterative decoding of the product of Reed-Solomon codes. It is given the block diagram of the device, which illustrates the relationships between the components of the device decoders iterations and describes the principle of the receipt and processing of data blocks in the device. The error correction device is N series-connected iterations decoders working on a pipelined basis. All its iterative decoders run in parallel, processing successively received data blocks from the channel. The structure of decoder iterations is disclosed and the functions of their constituent blocks are described with reference to the points of the decoding algorithm. The proposed device receives one code word symbol (8 bits) per 2 clock cycles and, when implementing a decoder on modern ASICs, is capable of providing a throughput of 2 Gbps at a processor clock speed of 500 MHz. This bandwidth allows the device to work in a continuous mode and processing data blocks at the rate of their arrival. Possible ways of increasing the capacity of the device are described. In addition, the article assesses the hardware complexity of the main units of the device, expressed in the number of gates and bits of memory required for its implementation using integrated circuits of a special purpose.