April 11, 2017
FCC Chairman Ajit Pai noted that there is interest by the FCC to open spectrum in the 95 GHz band, and above, for 5G applications, in a recent appearance at Carnegie Mellon University in Pittsburgh.
That is a “fur” piece from most of the current 5G discussions, which stop at about 39 GHz – and is largely uncharted waters.
We are all aware of the propagation challenges as frequencies rise but the support from the FCC is encouraging. In this E-band territory, spectrum issues do not scale linearly and it is unproven for mobile applications. In the mobile environment, things like Doppler, fading penetration and link budgets, combined with the need for much more signal processing and beam-forming, present more than just one set of challenges. And how to address the plethora of challenges up there has a lot of players looking for out-of-the-box solutions.
So far, these mmWave frequencies have proven themselves for various fixed wireless point-to-point (P2P) or point-to-multipoint (PMP) scenarios. This is likely where they will enter the 5G space, as well.
The attraction to the mmWave bands is multi-purpose. Some of the challenges for mobile are actually advantages for fixed wireless and will work nicely in segments of the wireless industry such as the Internet of Everything/Everyone (IoX). They also promise lots of available bandwidth, which has the potential for fiber-like speeds.
And, technical properties such as short propagation distances actually become an advantage for spectrum reuse. That makes these small footprints, coupled with wide channels, ideal for small networks such as high-definition distribution within a home or other contained area.
However, the most demanding challenge will be in the mobile arena, and that is simply due to the intrinsic propagation characteristics of frequencies of interest. However, mmWave frequencies are starting to be seriously looked at for mesh networks and various renditions of Wi-Fi-like networks.
While the target date for 5G is 2020, there is a wide definition of what is going to be 5G and some players are saying they will have spec-meeting product as early as 2018 (not those claiming 5G-like products). But the bottom line for the mobile/mmWave marriage is that it is unlikely it will be a major mobile platform by 2020.