[Editor's Note] GMSL (Gigabit Multimedia Serial Link), a high-speed, high-reliability, and low-latency multimedia transmission technology, is attracting a lot of attention as it is suitable for sensor, display, and camera networks in the development of SDV (Software Defined Vehicle). In particular, in SDV projects based on Zonal architecture, GMSL simplifies communication between ECUs and sensors and optimizes wiring with PoC functions. The combination of GMSL, Automotive Ethernet, and TSN optimizes communication between sensors, controllers, and HPCs, and the division of roles of each technology ensures optimal performance in securing real-time performance and stability. Meanwhile, Analog Devices (ADI) will introduce the core of GMSL technology and application cases in SDV trends under the theme of "High-Speed Data Transmission Technology for SDV - ADI GMSL" at the " 2025 e4ds Tech Day " to be held on September 9th. We met with ADI Director Seong-ho Son, who was in charge of the presentation, and heard about ADI's GMSL technology.



■ What are the differences and advantages of GMSL compared to existing interfaces such as FPD-Link III, CSI-2, and Automotive Ethernet?


In short, GMSL is a technology that is well suited to quickly and reliably transmitting camera or display data in environments such as automotive.

First, it is fast.

GMSL3 can transmit up to 12 Gbps on a single channel, allowing simultaneous transmission of 4K video, multiple camera videos, audio, and control signals.

Second, the cables are simplified.

It can transmit video, audio, and control signals over a single cable, and even supply power. This reduces wiring, reducing weight and cost.

Third, it can be sent reliably over long distances.

In vehicles, the distance between the camera and the ECU can be quite long, but transmission is possible up to 10 meters or more without any loss of quality.

Fourth, there is little delay.

Because it transmits the original data as is without compression or encoding, it is particularly suitable for functions that require real-time performance, such as ADAS or surround view.

Fifth, the fact that two-way communication is possible is also significant.

In addition to sending video, you can also change settings from the ECU to the camera or update firmware through the same link.

It is also possible to meet safety requirements by providing various diagnostic tools.

Lastly, it is resistant to electromagnetic interference and has a structure that allows for flexible connection of multiple cameras and displays, making it a perfect fit for today's vehicle architecture.

■ What are the design guidelines to consider when introducing GMSL into a camera, display, and sensor (lidar, radar) network during the SDV development phase?

GMSL enables high-speed communication between each Zone Controller and sensors such as cameras, lidar, and radar.

The number of GMSL channels and cable length must be optimized based on the physical layout of the sensors, and a balance between the processing power of each zone and the GMSL bandwidth is also important.

In addition, since it is a high-speed signal transmission, the following design must be considered.

○ EMI/EMC responsive design

Shielded cables and filtering are required to minimize electromagnetic interference during high-speed signal transmission.It is also important to ensure grounding and signal integrity in PCB design.

○ Ensuring real-time and stability

Real-time data processing is essential for ADAS and autonomous driving functions. Fail-safe design and redundancy must also be considered in case of failures.

○ Scalability and flexibility

The interface should be designed to be expandable, taking into account future additions of high-resolution displays or sensors. Compatibility with various sensor formats (CSI-2, DSI, eDP, etc.) must also be ensured.

■ If there are any representative SDV project cases that adopted GMSL, please introduce them.

Several OEMs have implemented GMSL in SDV to enable high-speed data transmission between each zone controller and sensors/cameras.

In particular, it contributed to simplifying communication between ECUs and sensors in the zonal structure and simplifying the wiring structure through the PoC (Power over Cable) function.

This will ensure efficiency and scalability of in-vehicle communication infrastructure.

GMSL provides the high-speed, highly reliable communication infrastructure that is at the core of SDV, playing an essential role in softwareization of vehicle functions, OTA updates, and expansion of AI-based functions.

In particular, the combination with Zonal architecture significantly improves the modularity, standardization, and scalability of vehicle design, and serves as an important foundation for building the SDV ecosystem.

■ How to combine network technologies such as GMSL, Automotive Ethernet, and TSN in software-defined vehicles to achieve optimal performance

GMSL is a high-speed serial link optimized for real-time transmission of image and signal data from sensors such as cameras, lidar, and radar.

In particular, it contributes to simplifying wiring through the PoC (Power over Cable) function.

Automotive Ethernet is a high-speed, highly reliable network suitable for in-vehicle inter-domain communication, connection to the central computing unit (HPC), over-the-air updates, and diagnostic communication.

TSN is an Ethernet-based real-time technology that enables delay-free data processing in safety-critical systems such as ADAS, autonomous driving, braking, and steering control.

Therefore, each technology can achieve optimal performance through division of roles.

GMSL is used for high-speed image transmission from the sensor to the Zonal Controller.

Automotive Ethernet + TSN is used for communication between Zonal Controller → HPC, data sharing between domains, OTA, and diagnostic communication.

TSN ensures real-time performance and reliability in Ethernet-based communications through priority-based traffic control, time synchronization, frame duplication, and removal.

■ What topics will be presented at the 2025 e4ds Tech Day?

We will understand the features and advantages of basic GMSL technology and examine how the SDV trend and GMSL technology can be integrated and developed.

■ A word to readers regarding the 2025 e4ds Tech Day

We ask for your continued interest and participation, and we hope today's insights will be helpful to your projects and vision.

Meanwhile, ADI will participate in the ' 2025 e4ds Tech Day ' to be held at the ST Center on September 9th and present on the topic of 'High-Speed Data Transmission Technology for SDV - ADI GMSL'. Applications for ' 2025 e4ds Tech Day ' can be made on the official website ( https://www.e4ds.com/conference/techday/ ).