The Inner Workings of 3D Authentication in Qualcomm’s 5G Smartphones

March 10, 2020 by Gary Elinoff

A new reference design based on Qualcomm’s Snapdragon 865 targets Infineon's time-of-flight sensor as the star of the show.

Consider a scenario in which you throw a rubber ball against a wall and count the time it takes to get back to you. Assume that the ball bounces off the wall at the same speed at which it hits. Now, you know velocity and time. Since distance = velocity x time, you can easily calculate the distance there and back; dividing by two gives you the one-way distance to the wall.

This simplified analogy gives you an idea of how ToF cameras work. ToF cameras bounce light beams off, for example, the tip of the young man’s nose in the image below. Other light beams hit every aspect of his face until you have the equivalent of a roadmap of that face. 


ToF block diagram

Time-of-flight illustration. Image used courtesy of Infineon


This roadmap defines the man’s face far more definitively than any picture could, and can provide a fool-proof method of identifying him. (For a more detailed explanation of this phenomenon, see Mark Hughes’ article explaining how time-of-flight sensors (ToF) work in a 3D camera.) 

It's no secret, then, why Qualcomm and Infineon are so interested in harvesting this technology for 3D authentification—now, with a new reference design. A key component of this collaboration is Infineon’s REAL3 3D time-of-flight sensor (ToF).


REAL3 3D ToF sensor

Infineon’s REAL3 3D ToF sensor. Image used courtesy of Infineon

The company claims that the ToF sensor is the most advanced available, and at 4.4 mm by 5.1 mm, Infineon says it's also the world’s smallest.


The Reference Design

The reference design for 3D authentication builds on the powerful foundations provided by these two major players. Infineon and Qualcomm assert that this reference design will be a boon to engineers designing smartphones and other intelligent, visually dependent devices. With much of the legwork done for them, OEMs will have a much faster time to market.

Qualcomm and Infineon have not yet unfolded the nuances of the reference design, aside from the baseline details: it is based on the Qualcomm Snapdragon 865 mobile platform and will use Infineon's 3D time-of-flight sensors. 


The Two Players

As accurate as ToF technology is, it requires an enormous amount of processing power—far too much for practical mobile devices. With 5G’s ability to upload vast amounts of data to the cloud, the computational tasks can be offloaded to remote servers.

Qualcomm is one of the world’s most important players in 5G—with its Snapdragon mobile platforms being listed as item number one on the company’s website.


Qualcomm’s Snapdragon 865 5G mobile platform

Qualcomm’s Snapdragon 865 5G mobile platform. Screenshot used courtesy of Qualcomm


This AI-based 5G platform can process an astonishing 2 gigapixels per second and provides for up to 7.5 Gbps of connectivity over 5G networks.

Infineon, the other member of this collaboration, is a $9 billion Siemens spin-off specializing in automotive semiconductors. As stated by Andreas Urschitz, President of the Power Management and Multimarket Division at Infineon (which also includes sensor business), “With the fifth generation of our REAL3 chip, we are once again demonstrating our leading position in the field of 3D sensors.”


Infineon's 3D imaging is sunlight independent

Infineon's 3D imaging is sunlight independent. Screenshot used courtesy of Infineon


Depth sensing ToF capabilities play a vital role in facial recognition for verifying payment transactions, enabling augmented reality, gaming, and 3D imaging. It has also been one of the major driving forces in the development of advanced driver assistance systems (ADAS).


The Significance of the Partnership

Qualcomm is justly considered to be the nation’s preeminent 5G developer, so the Snapdragon platform might be considered at least a defacto standard. Infineon is a recognized factor in imaging.

As Mr. Urschitz explains, "Today, the smartphone is more than just an information medium; it is increasingly taking over security and entertainment functions."

He goes on to state that "3D sensors enable new uses and additional applications such as secured authentication or payment by facial recognition. We continue to focus on this market and have clear growth targets. The collaboration with Qualcomm Technologies on reference designs using REAL3 image sensors underscores the potential and our ambitions in this area."


Featured image used courtesy of Infineon


Do you have experience with time-of-flight sensors? What are some advantages and disadvantages of designing with this technology? Share your thoughts in the comments below.