The Hardware System Of LPAQ8L Compression Algorithm Based On FPGA

With the rapid development of computer technology, data compression technology is the key to solve the storage and transmission of mass information.It can make the effective capacity of the disk and the effective bandwidth of IO larger, then the implementation of procedures will be accelerated.Compression can be either lossless or lossy. Lossless compression is widely used in aerospace, medical and other technical fields. Huffman coding and arithmetic coding are common com-pression technique.PAQ is a way of lossless compression that based on arithmetic coding. When it is used to compress the text,binary and image data,PAQ is optimized for the com-pression ratio.PAQ evolved the way of performing context mixing to combine several sta-tistical models intellectively,then it can predict the next symbol more exactly.Though, the compression ratio of PAQ is very outstanding,and its development is very active,it is too slow to use in practice.The bandwidth of PAQ is 0.5-0.7MB/s in PC.If the coming data is too much,then too much resource of CPU will be consumed.But we can use FPGA to promote its bandwidth and its compression properity.LPAQ was a "lite" PAQ,and it has little models and easy to archive on FPGA.The models of PAQ software sequential implement on CPU,so it has low execution efficiency.After we improving the program to make models execute parallel and implementing it on FPGA,its compression properity will be improved,the cost will be lower,and the PAQ will be more and more useful.The paper focuses on the discussion that how to improve the LPAQ8L arigorithm.We change the process method in byte instead of in bit,and narrow the space that models consuming in the case of little impact on the compression radio.When the LPAQ8L implement on the FPGA,we make all the models in pipelining processing and set feedback signal to make all the models work corrdinating.And every 8 bits in ervery model are made in pipelining processing to increase parallelism.The hardware compression system of LPAQ8L on FPGA has high compression ratio, it also has high rapid,it is 5 or 7 times faster than the software algorithm,and it will be useful in practice.