In-depth understanding of the OTA upgrade mechanism of IoT devices

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

In-depth understanding of the OTA upgrade mechanism of IoT devices

Posted Date: 2024-01-22

In 2020, Tesla released an OTA update, and car owners can obtain the seat heating function through this system update. At that time, this news shocked the car industry and all car owners. At that time, everyone did not regard cars as smart devices that could be “upgraded”. Now three years have passed, and car owners are no longer surprised by OTA upgrades from various car companies. Today, when smart devices have become popular, everyone is already very familiar with the concept of "software upgrade": software can be upgraded, personal computers can be upgraded, mobile phone systems can be upgraded... But for the upgrade of Internet of Things (IoT) devices, everyone may still Feel strange and curious. Why can seats or steering wheels that do not originally have heating functions gain new functions through just a software upgrade? This will lead to our protagonist today——OTA.

What is OTA?

OTA(Over-The-Air, over-the-air technology) is a wireless transmission technology used for remote updates and configurations between IoT devices. OTA refers to remotely updating or upgrading software or firmware in embedded systems through wireless communication networks.OTA updatesis a convenient method for pushing new features, improved performance, security patches, or other changes to embedded devices without requiring physical contact with the device or manual user intervention.

·OTA simplifies the device update and maintenance process. Traditional software update methods often require users to take their devices to a service center or use a wired connection for updates, which is time-consuming and cumbersome. OTA technology allows devices to automatically receive and install updates, greatly saving time and energy. ·OTA technology improves the reliability and security of equipment. By regularly updating device software, potential security vulnerabilities and performance issues can be fixed, thereby reducing the risk of device attacks and damage.

·OTA technology can realize remote diagnosis and troubleshooting, helping users solve problems faster.

In the field of Internet of Things, OTA technology is widely used in various devices, such as smart homes, smart cities, industrial automation, etc.

Features of OTA solutions

Faced with the challenges faced by remote updates, the remote update solution for the Internet of Things platform needs to have the following characteristics.

Short time and high efficiency

The IoT platform should reduce the time of remote upgrade as much as possible and improve the efficiency of upgrade. ·By controlling the size of the upgrade package, differential grouping is used to reduce the size of the upgrade package and reduce remote network transmission time. ·Improving upgrade flexibility through in-module upgrades.

·Add breakpoint resumption function to avoid data retransmission caused by terminal failure or communication interruption and reduce data transmission time.

Reasonable use of wireless resources to improve service efficiency of terminal updates

In order to improve the efficiency of wireless resource usage, the terminal remote update service should implement multi-task concurrency. One task corresponds to a remote update plan, which includes a group of remote terminals to be updated. At the same time, in order to ensure the normal use of other terminal services in the same wireless area, the IoT platform should limit the number of terminals that perform update operations.

High reliability

High reliability is forEnsure the efficiency of terminal updates. ·The management and control of remote updates must be precise, accurate, and intelligent. The IoT platform should be able to perform validity checks based on the status of the specific terminal (such as version, file type, upgrade package size, etc.), and then trigger the terminal remote update process. ·By introducing the state machine mechanism, controlling the remote update process and implementing exception handling, it can ensure the coordination of control between the terminal and the cloud and reduce the risk of remote update operations.

·During the remote upgrade process, in order to avoid possible errors or loss of upgrade package data, consider using the upgrade package verification mechanism to ensure the integrity of the upgrade package, use reliable transmission protocols to ensure the reliability of data transmission, and use the Internet of Things The platform's retry strategy ensures the stability of the transmission and upgrade process.


Universality means that heterogeneous terminals in different fields and types connected to the IoT platform should use the same terminal update process. This can minimize the maintenance cost of remote terminal updates, achieve user self-service and self-management, and enable large-scale updates to heterogeneous terminals. ·The terminal remote update solution needs to separate the control flow and business flow, and the control flow is not affected by the environment where the terminal is located. ·The control flow is carried using standard and open international standard protocols to ensure the implementability of the technical solution.

·Compatible with upgrade packages, supports personalized upgrades of business flows, and supports differential package upgrade services provided by third-party differential service providers.

Reference architecture and service process of OTA system

The structure of the IoT cloud platform remote update system consists of two parts: the server and the terminal.

The structure of the remote update system of the Internet of Things cloud platform

Remote update serverIt is a functional module of the Internet of Things platform, which mainly implements user self-service and remote update management and control functions. User self-service means that users formulate remote update tasks and query remote update status through the portal. Task formulation includes update versions, upgrade packages, terminal groups to be upgraded, update policies, etc.; remote update management includes update triggering, upgrade package download and installation control, and policy execution control when download and installation fail.

The generation and download of the upgrade package is completed on the server side and supports two methods:

One isThe IoT platform provides download services for terminals to be upgraded.this method is that the user uploads the upgrade package through the portal, and the IoT platform is responsible for the management of the upgrade package;

The other isA third-party differential server provides the generation and download of differential packetsin this way, users need to select the access address of the third-party differential server when formulating tasks.

No matter which method is used, both the server and the terminal must supportBreakpoint resume function.

During remote updates, the terminal needs to download and install the upgrade package and report the installation results according to the instructions of the server. Terminal downloads should support breakpoint resume downloading and upgrade package verification. Terminal installation should support installation and fault tolerance functions. Fault tolerance means that the terminal isolates and handles faults during the installation stage to ensure that the normal operation of the terminal is not affected when the installation fails.

The remote update service process includesUpdate task formulation, update triggering, upgrade package download and installation4 stages.

OTA service process diagram


In the field of Internet of Things, OTA technology is widely used in various devices, such as smart homes, smart cities, industrial automation, etc. However, OTA technology also faces some challenges: First, due to the wide variety of devices, different devices may require different OTA technologies and protocols. This requires developers to carry out customized development for different devices and application scenarios, which increases development and maintenance costs.

Second, the security and reliability of OTA technology also need to be considered. If there are errors or interruptions during the OTA update process, it may cause the device to not work properly or data to be lost.

Overall, OTA technology provides a more efficient and secure way to update and maintain IoT devices. Although it faces some challenges, as technology continues to develop and improve, we believe OTA will play a greater role in the future.

Review Editor: Huang Fei

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