A new code compression method for FOTA

This paper presents a new compression method for compressed Firmware-over-the-air (FOTA) that reconstructs a new compressed version from an old compressed version of firmware stored in NAND flash memory. The compressed FOTA requires a small delta that minimizes the amount of update data and an efficient compression method that provides fast encoding and decoding to achieve fast updating and extraction. A fast dictionary-based compression algorithm for the program code is introduced. With a high compression ratio, our method provides relatively fast encoding and very fast decoding. We demonstrate that the compression time during the update process can be reduced by utilizing the copy information stored in the delta without increasing the size of the delta. We present some experimental results to show the impact of this method in terms of the compression ratio, extraction time and updating time.