ETAO: Symbol mapping transformation method for text compression

This paper is proposing a novel idea for text transformation based on mapping single letters form the standard alphabetical order into the same set of single letters reordered by their relative frequencies. This method can be used as a complementary algorithm to enhance the statistical compression techniques. We have designed and implemented an algorithm called ETAO transformation method. It has been found that the Average Code Length (ACL) could be reduced with amount of about 5%, when using Huffman or Arithmetic encoding techniques as backend.