Lossless Data Compression And Decompress The Software And Hardware Implementations

With the development of the science, we need to deal with more and more information. The large amounts of data take a lot of storage space and a lot of bandwidth to transport. It brings a lot of inconvenience to the storage and transmission. So, the data compression becomes more and more important. But the software compressing the data will slow down the speed of the system, because it will cost much resource of the system. This research topic is raised on the basis of this background.Certain improvements are made on the basis of the original LZW algorithm. Finally, the system is realized by FPGA. First, the paper made comparison among the most widely used algorithms of lossless data compression. In the end, the LZW algorithm is selected as the algorithm of this paper.. Then, C language is used to describe and simulate the compression and decompression phases of the algorithm. Then some optimization of this two phases is made. During the compression, the way of updating the dictionary is optimized. The new algorithm rebuilds part of dictionary instead rebuilding the whole dictionary when it is full. So that the new dictionary update method is not only increase the compression rate, but also improve the adaptive characteristics, which allowing LZW algorithm superior to other lossless compression method. In the decompression stage, the formation of the original term is extended. The new entries to the dictionary reducing the number of queries to improve decompression speed. Then the system is divided into several modules, and all of them are simulated by Modelsim. In the end, the Spartan-3A by XINLINX was chosen to realize the system and the function of it was proven by test.Finally, the test of the software and hardware show that the optimized algorithm has improved efficiency.