How Important is Latency to 5G Users?

According to Ericsson, user experience is all about “time-to-content” – in other words, how fast does my video start or my webpage load after I click to open it? Based on a study the company recently conducted, they found that latency is rarely a factor when it comes to user satisfaction. 

Reiner Ludwig, Strategic Product Manager in the Business Area Networks at Ericsson wrote a blog on just this – “Latency hardly impacts smartphone user experience in advanced 5G and 4G networks.”

In describing the study, Ludwig says they used high-end smartphones in a controlled environment. These were all requesting popular content (YouTube, Instagram, Amazon, eBay, Uber, etc) in an automated way. 

“For the latency measurements, we have ensured that sufficient up- and download speeds were available to the devices at all times: an uplink throughput “at click” of at least 1 Mbps and a downlink throughput “at click” of at least 20 Mbps,” he said. 

Tools and guidelines for the study were provided by Google on web.dev. This allowed them to see the relationship between time-to-content and latency, and time-to-content and up- and download speeds.

What is Latency?

Ludwig describes latency as the time it takes for a device to send one small ‘echo’ packet to the serving content server and the corresponding ‘echo-reply’ packet to return to the device. This period of time is also called the round-trip time. 

What isn’t latency? It’s NOT the same as time-to-content. This is where many people tend to misunderstand. 

Where is Low Latency Most Helpful? 

While low latency is important to online gamers, it’s more crucial for machines. 

“Machines, not humans, can benefit from the ultra-low and ultra-reliable latencies that only 5G can provide. For example, think about video-controlled high-precision robots in a smart factory. Here, you might see latencies below 10 ms, i.e., ultra-low, and without latency spikes exceeding 10 ms, i.e., ultra-reliable. Meeting these tough requirements is one of the key drivers behind Ericsson’s launch of a new product offering targeted at Time-Critical Communication,” says Ludwig.

Surprisingly, us humans are hardly able to tell the difference between 30 and 50ms of latency. Ludwig explains that 5G and 4G latency in the U.S. is usually less than 50 ms. This came from a 6 month analysis of Ookla’s speed test results, which were gathered from all across the U.S.

The takeaway here is that 5G (human) user experience is determined by speed, not much by latency. However, Ludwig admits, “Once 5G use cases such as virtual and augmented reality become mainstream, some aspects might need to be revisited.”

To view Ludwig’s blog in its entirety, see here.