Optimisation of PPMC model for hardware implementation

Abstract

The development of new and more powerful applications in data communications and computer systems has required an ever-increasing capacity to handle large amounts of data. Lossless data compression techniques have been developed to exploit further available bandwidth of such systems by reducing the amount of data to transmit or store. They have been implemented in both software and hardware. The former approach provides good compression ratios but presents speed limitations. The latter approach offers the possibility of high-speed compression to suit the most demanding applications. Current available hardware implementations are based mainly on LZ (Lempel-Ziv) class of compression schemes. Experience suggests that classical statistical methods, particularly PPM (Prediction by Partial Matching) class of algorithms, are impractical for being too slow and resource hungry for hardware realisation. However, there seems to have been relatively little work looking at the potential for reorganising and restructuring the algorithm for hardware implementation. This paper presents a version of the PPMC class of algorithms structured for efficient hardware support and analyses the issues of its hardware implementation.