Verizon shocked many by specifying 30 ms as the latency on its 5G network. Its top officials predicted much faster connections; many, especially politicians, talk of 1 ms. In multiple independent tests, Verizon usually was somewhat better than 30 ms, down to 24 ms In Telstra in Australia, Daniel van Boom and Ian Knighton of CNET found 22 ms in a test. A thoughtful article. A test in Korea returned 25 ms. Several in England were 30-35 ms.
The latency can be brought down by putting special servers inside the carrier system, an Edge Network. Expect 15-25 ms depending on where in the network the servers are deployed. Most will be one to three routers from the cell, perhaps at a C-RAN or exchange. Some will be further back in the network.Verizon is also improving the transport and backhaul on its system, which could be almost as effective as a regional edge network.
1 ms works in the lab, but less than 15-20 ms will be rare on public networks for years.
For almost all purposes, the meaningful latency is from the phone to the server it's trying to reach. If servers were frequently placed at the cell, that could be 10-15 ms. Few if any carriers are planning that, however. An industrial 5G network can have a server at the 5G cell, bringing latency down to about 10 ms.
URLLC, the next version of 5G, will reduce all the above figures by ~5ms. In-building and similar locations with URLLC should be able to get down to 4-7 ms, mostly after 2023.
DT and Vodafone have started offering Edge, on a system designed by MobiledgeX. Nicki Palmer says Verizon Edge will be commercial by yearend 2019. China will build an incredible network, bringing over one billion people within 25 ms of a server.
The "air latency" of today's 5G is 8-12 ms. That's meaningful for a network architect but has nothing to do with user experience. The "1 millisecond" was an aspirational goal to promote 5G, not really expect for many years.