Updates on Millimeter-wave 5G (Part 2)
Many countries have yet to release, or license, mm-Wave spectrum for service providers to use or lease. The US, via the FCC, just auctioned seven 100 MHz blocks of spectrum in the FCC Auction 102. This mm-Wave spectrum covers the lower and upper 24 GHz spectrum, between 24.25 GHz and 24.45 GHz, and 24.75 GHz and 25.25 GHz. 2904 out of 2909 licenses were won, establishing what is commonly deemed as a success of the second high-band auction [1, 2]. FCC Auction 101, the first high-band auction, licensed spectrum in the 28 GHz range, and where only available for a portion of the country. The 20 GHz mm-Wave may be the most likely spectrum for 5G to start, at it appears that there is more action around the globe toward enabling the 20 GHz spectrum for commercial use.
However, there are currently some early “5G” services purely for Fixed Wireless Access that operate other areas of the mm-Wave spectrum. For example, internet provider Starry, uses frequency bands between 37 GHz and 40 GHz to provide their service, which reportedly has a capacity of 5 Gbps and a coverage radius of 2km. This type of internet service is not traditional cellular service from a base station to a mobile device, but instead a last-mile internet connectivity and service that delivers internet to fixed customer transceivers placed on buildings.
Early 5G build outs and tests all appear to be sub-6 GHz (mid-band) or low-band (sub-1 GHz), with only hints that some wireless operators may use mm-Wave spectrum alongside sub-6 GHz in select urban areas in the future. For example, Verizon’s early 5G deployments in Minneapolis and Chicago only offer sub-6 GHz 5G, and though impressive, are only suggested to reach average speeds to 450 Mbps. There also appear to be substantial service issues with Verizon’s 5G, where service is spotty and far from full, or even adequate, and coverage .
One of the big hurdles of implementing mm-Wave 5G user equipment (UE) mobile services is impacted by both the challenge of deploying and implementing multitudes of multi-element mm-Wave antennas, as well as implementing complementary hardware in a handset. There are early modems and beamforming/MIMO SoCs that are designed to enable more compact and cost effective multi-element antenna arrays, commonly considered necessary to provide mobile 5G service. For the most part, these radio devices have only recently entered the market, or are just now being evaluated by select manufacturing partners.
Though mm-Wave 5G is still nebulous, there are some certainties. Wireless operators will want to recoup their investments in mm-Wave spectrum by deploying some variety of mm-Wave 5G. Moreover, it is likely that as the data revolution continues, more areas and Telco’s will invest in building out higher performance core and backhaul networks to service higher demand RANs. Lastly, there will likely be a substantial amount of real-world testing before Telco’s move toward deploying mm-Wave 5G given the variety of novel scenarios and factors mm-Wave 5G presents compared to sub-6 GHz wireless services.