Latency: What it is and why it matters to the next generation of technological advancement

How do professional baseball players hit a 100 mph fastball? Consider that there’s a 100 millisecond delay between seeing an object with the eye and processing that information in the brain. By the time the eye can actually see the path of the ball and process the necessary information to swing the bat, the ball should be past the batter and safely in the catcher’s mitt. 

The short answer is, exceptional athletes don’t wait to see the ball. Research shows that neurological activity in the V5 region of the visual cortex essentially enables them to “see” something that hasn’t happened yet. Their brains compensate for the delay, or “latency,” by predicting the motion of the ball, and they swing according to that predictive vision, thus catching up to the fastball. 

Any online gamer who has learned to shoot slightly ahead of where the target is headed—to account for slow connection speeds or refresh rates—will be familiar with the frustration created by lag and can attest to the link between reduced latency and successful outcomes.

Increasingly, however, in arenas like telesurgery, intelligent transportation systems, and remote-controlled robots, latency isn’t just frustrating, it can be critical. Certainly, display technology—including resolution and refresh rates—continues to improve, which reduces lag times. But more responsive, more reliable data transmission promised by future 5G technologies are what’s needed for the latency-critical services that will shape our future.

Let’s take telesurgery as an example. The benefits of telesurgery and surgical telementoring are clear: specialized surgeons can assist less experienced physicians who are miles away; patients in remote locations can receive surgical care faster without traveling; and robotic devices may actually supply greater surgical accuracy than laparoscopic procedures. 

But latency remains the biggest obstacle to the widespread adoption and commercialization of telesurgery, along with the attendant medico-legal issues. 

Mehran Anvari, scientific director and CEO of the Centre for Surgical Invention and Innovation in Ontario, is one of the world’s leading robotic surgery pioneers. He says that even for hands-off telementoring, a half-second delay is too long for a high-quality experience. 

For telesurgery, Anvari typically works with a latency of 175 milliseconds, so predictive adaptation is necessary. Beyond 300 milliseconds (which is about the time it takes to blink), he says “it becomes very, very difficult for your brain to actually adapt to that type of time delay.” Keep in mind that Anvari is one of the most gifted specialists in telesurgery today. His expertise and predictive abilities are likely far greater than the average surgeon, which means latency times need to come down significantly. 

Indeed, IEEE, a professional association devoted to technology advancement, puts acceptable telesurgical latency times at 1 to 10 milliseconds.

For telesurgery and other latency-critical services, like self-driving cars, automated public transportation, or smart grids (controlling the production and distribution of electricity), 5G networks may be the difference between potential and reality. Testing has shown the potential for 5G networks to be 10 to 20 times faster than today’s 4G. “We’re talking single-digit millisecond latency with 5G networks,” according to Sanyogita Shamsunder, Vice President of 5G Ecosystems and Innovation at Verizon.

For most of us, the difference between 175 milliseconds and a single millisecond is imperceptible. But in arenas where low latency is critical, 5G lays the groundwork necessary to make them possible.

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