5G

5G is the fifth generation of mobile communication systems and the successor to 4G LTE. The figures usually quoted for it — 20Gbps, 1ms, one million connections per km² — come from ITU-R Recommendation M.2410 (November 2017), which sets the minimum technical performance requirements for IMT-2020. The 20Gbps figure is a downlink peak data rate, the 1ms figure is the latency assumed for ultra-reliable low-latency communication (URLLC), and one million connections per km² is the connection density assumed for massive machine-type communication (mMTC). Each is evaluated against a different usage scenario, so a single handset does not meet all three at once. The same requirements set a separate figure for what users actually experience: 100Mbps downlink and 50Mbps uplink. The 20Gbps peak is an upper bound under ideal conditions. Commercially, South Korea launched the world's first nationwide 5G network in April 2019, and service went live in parts of a few US cities on the same day. Japan's three mobile operators began commercial service in March 2020.

Where 5G matters most for QR codes is the quality of the content that opens after a scan. On 4G, loading a video or an AR experience after scanning meant a wait, and that wait drove users away. As 5G leaves more headroom in both bandwidth and latency, there is more room to shorten it. What actually determines that wait, though, is the whole chain: radio conditions, cell congestion, the processing power of the handset, and the design of the delivery side. A requirement figure written into the standard does not translate directly into experience, so the work on the QR code side — keeping the landing page light, lazy-loading images and video — still has to be done.

Large-scale events are another area of expectation. When tens of thousands of people scan QR codes at the same time in a stadium or concert hall, 4G repeatedly produced the complaint "I scanned it but the page won't open". With 5G, congestion is being addressed through designs that raise per-cell capacity and through temporary cells or local 5G deployments brought in for the venue. Note that the connection density of one million per km² mentioned above is a requirement figure framed around massive machine-type communication; it is not a direct measure of how a network copes when an audience pulls high-resolution content all at once (the enhanced mobile broadband, or eMBB, case).

In IoT applications, a common pattern is to scan the code affixed to a machine on the factory floor and display its operating data. What that needs is mainly bandwidth and a stable connection; streaming operating data to a display is not in itself premised on ultra-low latency. 5G's ultra-low latency (URLLC) was built out in 3GPP Release 16 and presumes a standalone (SA) configuration with a 5G core. On a non-standalone (NSA) configuration, which leans on the 4G core network, the latency written into the requirements does not hold. Where low latency is used for machine control itself, the typical arrangement is a local or private 5G network rather than the public one.