Takeway: Decent 5G until around 2025 will be mostly mid-band, 2500-4200 MHz. Frequencies lower than 2100 MHz essentially deliver 4G capacity. Millimeter wave, 20 GHz and above, can deliver gigabits but will be rare until the middle of the decade or later. It’s expensive, and the carriers don’t see much market.
Heretical but true: 5G delivers little more capacity than 4G, in the same spectrum and using the same antennas. T-Mobile US CTO Neville Ray estimates that in ideal circumstances, 5G delivers between 19% and 52% more capacity. “Ideal circumstances” are years away; below 2100 MHz, 5G is slower than decent 4G. 5G in lower frequencies adds nothing to capacity and has few if any practical advantages. It’s great or.
Dwight Silverman of the Houston Chronicle tested AT&T 5G around the city. Most speeds were in the 75-125 Mbps range typical of AT&T’s latest 4G. In the lower right, the single mmWave radio tested over 800 Mbps.
Mid-band, from 2500 MHz to 4200 MHz, is the primary 5G band in use. 5G can efficiently use 100 MHz bands, which usually deliver speeds of 100-450 Mbps and occasionally more. Like 4G, theoretical and lab speeds can go over a gigabit, but that’s misleading.
100 MHz contiguous is the standard 5G band, although not all carriers can achieve that. The lower part of the band has longer reach. The 2500 MHz spectrum of T-Mobile US and China Mobile is golden. (Both actually have 160 MHz, beyond the 5G specifications. Huawei tells me its radios can use all 160 MHz.)
Millimeter wave, from 20 GHz to over 60 GHz, can work with 400 MHz bands and deliver gigabits to many. Initially, it was the only 5G. It is in very limited use until 2022 and later. No carrier needs the capacity before 2022 and many are fine just using mid-band until late in the decade. Because shorter wavelengths have less reach, they cost more to deploy.
The industry, at 3GPP, decided to call anything that ran “5G NR” software “5G.” I don’t think something slower than decent 4G should be called 5G, but that’s become the norm.