Verizon & Korea are building. NTT DOCOMO & China Mobile close. Many others mostly holding back, doing little until 2021-2023.
2019 for mobile phones, Qualcomm promises, as TSMC ramps 7 nm process to produce the chips.
Latency will be 5-10 milliseconds to the cloud controller intelligence.
1-2 milliseconds will be measured from the tower to the phone, but that's meaningless until and unless intelligence moves to the edge. That's likely very rare for a decade because there's no apparent market for 1 ms. Most "use cases" are bogus according to experts in connected cars, virtual reality, and telemedicine. Gerhard Fettweis's Tactile Internet is inspiring but years or decades away most places.
July 2017 Gigabit LTE is real in 2017. So is 5G Massive MIMO. 5G mmWave to fixed antennas is likely 2018, with mobile to follow. China, Japan, Korea, and Verizon U.S. have planned $500B for "5G," with heavy investment expected 2019-2021.