As noted in my introductory post, the advent of 5G will be paced by three market forces: technology, policy, and business model. My last post referenced the past but our topic is predictive, so let us cover the future of perhaps the most visible of all 5G enabling technologies:
Roger’s claim: Millimeter-wave for eMBB will not be commercial in 2020.
First a couple of clarifications: My casual reference to “millimeter-Wave” (mmWave) means the use of any carrier above 6 GHz; and “eMBB” implies “mobile” and “multiple-access.” “Mobile” (mobility) means tolerance to group-delay at greater than walking speeds combined with handovers and Quality-of-Service (QoS) management from the network. “Multiple access” means managing many diverse users and use-models simultaneously. This means contiguous bandwidths of perhaps as much as 1 GHz and associated peak data-rates on the order of 10 Gbps.
I have tested my prediction with network equipment manufacturers
(NEMs) and mobile net work operators (MNOs) and the initial responses have ranged from “You are right” to—are you ready for this?—“You are wrong.” Digging deeper yields greater clarity around the three big drivers, and all are stacked against mmWave.
Technology will not be ready. In spite of some impressive demonstrations of high-speed links—even mobile ones—in the rarified mmWave bands, the technology still has far to go. Although 802.11ad provides affordable mmWave communications with a truly elegant implementation, it is neither mobile nor multiple-access. Just a few examples that highlight the technical challenges include random-access, tracking, fading and blocking, and transceiver front-end design. Random-access and tracking alone are daunting: Where do you point your antenna first? How do you keep it pointed the right direction? How do you manage a directed and directional handover? All of these are getting serious attention so by 2020 we will likely have answers but probably not commercial deployment.
Policy will not be in place for licensed bands above 6 GHz. Policy always lags technology, and spectrum policy is no exception. Five simple assumptions reinforce this position:
- Policymakers must declare which bands will be licensed for mobile.
- Licensing structure must be determined.
- Licenses must be allocated to the licensees, typically through auction.
- The incumbents must be re-farmed.
- The legal fallout must be resolved.
Even if we overcome the plodding precedents of the past, doing so across each facet in the next three-plus years seems virtually impossible.
“But,” I hear astute readers exclaim, “on July 14, 2016, the FCC paved the way to aggressively license mmWave for 5G!” This is indeed a positive step, and arrived sooner than I expected. Arguably, the FCC also covered the second bullet—but getting through the others, and especially the last one, will take time.
Cost and business model will not be ready for associated applications. Mobility using mmWave will require much greater density of base-stations due to issues with signal propagation. Each new site will require backhaul (and perhaps fronthaul) capacity and speed and this is unprecedented. User equipment (UE) will require multiple antennas and perhaps multiple mmWave bands.
All of this new technology will require investment by MNOs and users. Killer apps will have to go way
beyond 4K YouTube cat videos to drive the average revenue per user (ARPU) necessary to justify these investments. Many of the envisioned applications involve augmented reality (AR) or virtual reality (VR), implying costly UE devices. I do believe this is coming—demand for higher data rates is inexorable—but resolving this host of issues in less than four years is a longshot at best.
One more counterargument is Verizon’s claim it will commercialize mmWave 5G capability in 2017. But they have also explicitly stated that this is for fixed wireless only, at least at first. This is an admirable goal and I have no doubt it will be accomplished, but it does not achieve the “mobile” part of eMBB.
Will we have commercial mmWave systems in 2020? We already do with 802.11ad. It is possible that even policy will move fast enough for MNOs to implement fixed-wireless capabilities in licensed bands. But for mobile, multiple-access services so we can experience our 8K YouTube cat-videos with VR goggles, I say we have a few more years to wait. I actually hope someone proves me wrong—I welcome all comers!