Compression method for ECU software updates

Bugs in electrical control units (ECUs) in vehicles are increasing in accordance with the increasing complexity and scale of the ECU software. Thus, manufacturers need to recall their products. Moreover, upgrade functions for the ECU software or security functions will be required for connected vehicles. Therefore, a software function for reprogramming ECUs over the air (OTA) will be required after shipment. The most important issue in OTA updating is to reduce the update time. In many cases, differential compression technology is applied to the update data. However, it is difficult to apply this technology for some ECUs in which the RAM size is smaller than the size of the erase block unit. In this case, compression technology should be applied. We evaluated the many compression technologies for application to this type of ECU, proposed a suitable algorithm, and discuss improvements to it to reduce the update time for these ECUs.