SMS compression using arithmetic coding modification

The proposed compression mechanism in this paper has been researched plainly in mobile phone that uses Android operating system. The aim of this proposal is to optimize the maximum character capacity of SMS body. Every character in SMS is mostly encoded in 7 bit and the maximum capacity of one SMS is only 1120 bit. Those SMS characteristics require a very efficient compression method to compress SMS Arithmetic coding is a compression mechanism that works by converting a data message to a real code number between 0 and 1. Arithmetic coding provides nearly optimal data compression. However, it requires additional memory space in compressed data to save arithmetic coding probability table for decompressing the compressed-data. Besides, it requires high precision and effective encoder-decoder to calculate and represent its code number it. In very limited data space like SMS, the need of additional memory space to save arithmetic coding probability table is inefficient. It will make the compressed-SMS size bigger than the original SMS (uncompressed SMS) size.Based on the research, the compression ratio of proposed compression mechanism is vary depends on the content of SMS. The average compression ratio of proposed compression mechanism is 71%, while the maximum compression ratio is able to reach less than 25%, i.e. 500 character SMS can be compressed to 121 character SMS.