OTA Reprogramming / Delta Compression Engine

High-speed, secure, and reliable wireless software updates using Fujitsu's original delta generation technology, compression technology, and secure distribution technology

OTA Reprogramming

The wireless software update (OTA Reprogramming) that Fujitsu provides uses secure distribution technology based on the know-how cultivated through smartphone and mobile phone development. Electronic Control Unit (ECU) software updates are being regulated globally and in Japan under the United Nations’ WP 29 regulations, and updates are being made in accordance with the regulations.


  • Software Update

    Fujitsu's original functions enable fast, safe, and reliable software updates for automotive ECUs.

  • Update Management

    Regulatory updates can be managed at OutCar centers.

  • Improve Productivity

    Software updates are available at any time and location (from development after delivery to users).


  • Software update management enables third-party certification (public key certificate authority) via update logs.

  • The Delta Compression Engine, using Fujitsu's original algorithm, generates and restores delta compression.

  • The OTA administrator manages the version of ECU programs, the dependency between ECUs, and the software configuration corresponding to regulations (RxSWIN) in a unique hierarchical structure.

  • Firmware OTA can be deployed to application OTA or profile OTA.

Comprehensive Coverage of Development, Manufacturing, and Sales

Comprehensive coverage of development, manufacturing, and sales Comprehensive coverage of development, manufacturing, and sales

System Configuration Diagram

System configuration diagram System configuration diagram

Delta Compression Engine

Fujitsu's Delta Compression Engine is a delta reprogramming package that accelerates ECU reprogramming. This package enables the reprogramming of only the part where the change occurred, using the delta information between the old program and the new program of the ECU.


  • Time Reduction

    Significant time reduction is achieved by reprogramming only the parts where changes occurred.

  • Data Traffic Reduction

    The delta information used for reprogramming is significantly smaller than the size of the new program (up to a 99% reduction), and this enables a reduction in the amount of data traffic for distribution via public lines, etc.

  • Cost Reduction

    Cost reduction and the improvement of vehicle user's convenience are achieved by combining the Delta Compression Engine and OTA reprogramming.

  • Improve Productivity

    The improvement of productivity is achieved by increasing the speed of reprogramming at automobile factories.


  • Support that saves memory:
    Low memory footprint (minimum required resources: RAM of approximately 2.5 KB, ROM at approximately 4.5 KB)

  • Higher compression ratio:
    Fujitsu's original compression algorithm "ELC" and the additional choice of "LZMA" for higher compression ratios

  • Rich set of parameters: Total of 2,448 delta generation parameters and two types of delta information (delta compression, and with compression only) available

  • MISRA-C (※ 1):
    Complies with MISRA-C: 2012 (※ 2)
  • ※1
    MISRA-C: Standard coding rules for automotive software
  • ※2
    Complies with all mandatory items in all rules; mandatory items and recommended items are handled with some exceptions (deviation manual included for non-compliant items).

Programs Delivered from the Cloud

Significant Reduction in Reprogramming Time

Example of Reprogramming Time

Example of reprogramming time in program size = about 1.9 MB, communication path = CAN 500 Kbps

Compatible with WP.29

At the United Nations World Forum for Harmonization of Automobile Standards (WP.29) held in June 2020, international standards for cybersecurity and software updates for automobiles were established. There are two stipulated areas: cybersecurity (CS) and software update (SU) areas. As for SU, both wireless updates (OTA) and wired updates are covered. Automobile manufacturers are required to comply with Software Update Management System (SUMS) requirements from the aspects of processization and IT systematization.

Software Update Management System (SUMS) Process

The SUMS process includes wired reprogramming as well as OTA reprogramming.

Campaign Management Information on software updates should be documented and promptly provided to authorities upon request.
Software Management
Configuration Management
・Process that can update RxSWIN before and after software update
・Process of managing which ECU RxSWIN is associated with
・Verification process that can determine if the related RxSWIN needs to be changed when the ECU software is updated
Security Software integrity verification data (including initial and updated versions)

Fujitsu OTA Design and Implementation (SUMS)

Total support, from consultation for WP.29 gap evaluation to OTA

Existing OEM’s Process/System Existing OEM’s Process/System

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