Is VR the killer app for 5G? – Part 2

Article By : Larry Desjardin

In the second part of the series, Larry Desjardin continues to dig deep into the opportunities and challenges represented by 5G.

IMS hosted a “Micro-Apps” theater, which was located in the center of the exhibition, and consisted of short, rapid-fire presentations. I sat in a couple that were 5G focused. Mike Millhaem, also of Keysight, gave a presentation titled “Now You See Me, Now You Don’t<img alt="” discussing mmWave signal propagation and implications for networks and tests. Mike showed measured results of 5G channel sounding, and accentuated some of the challenges mmWaves present.

[Channel sounding wall]" src="https://images.contentful.com/rphcxwngga0b/5CE9DoXhkW2IusqkU6A6kI/0d21179a68c89d376c8e8418b236b5e4/Channel_sounding_wall.jpg" />
Figure 1: *The above shows a Keysight 5G channel sounding system being rolled in front of a brick wall and window to record the channel characteristics. To the right shows the results versus time. Even small changes in surface cause dramatic effects. This shows the difficulty in predicting mmWave behaviour. (Images source: Keysight Technologies) *

I caught up with Mike later in the conference to get his take on 5G applications. He also pointed to the high density stadium case, but added another one, ”we don’t know.” Not being flippant, Mike’s point was that it is difficult to predict what new applications can surface when there is a dramatic change in bandwidths. Would we have predicted that 3G/4G would have enabled new taxi companies like Uber or Lyft?

I wandered to the National Instruments booth and caught up with David Hall and Charles Schroeder for the same discussion. David’s answer to my question dealt with overall capacity. Sure, I could download at 70Mb/s now into my iPhone 5S, but we couldn’t all do that at the same time. Here it comes down to pure spectral capacity, not peak rates. In some ways, this is the generalized case of the stadium application- is there enough total bandwidth available to feed a city? Fair enough.

__Figure 2:__ *Screenshot of 4G LTE speed test performed on the author’s iPhone 5S on the conference floor. But what it everyone wanted this top speed?*

My final opportunity to pose the question came during a panel discussion moderated by Eric Higham of Strategy Analytics, with senior panel members from Analog Devices, Anokiwave, Keysight, NI, and Rohde & Schwarz. The panel was titled, “The 5G and IoT Conundrum”, where the panelists described the opportunities and challenges represented by 5G.

I played devil’s advocate one last time- asking what would drive these 5G investments versus continued advancements of 4G technology.

All participants were adamant that 5G service providers were racing for deployment. Again, the stadium use case and virtual reality were brought up. Also mentioned was the total capacity issue – I might have gotten 70Gb/s download rate, but it would have been slower if everyone in the conference had tried. The moderator described the competitive dynamics that are leading to the race – no service provider can risk not investing in some trials just to be left behind when the bandwidth intensive applications hit. As I described, only somewhat in jest, they all feel they need to belly up to the saloon’s bar, and rest their pistol on the counter.

So, what does this all mean? Here’s my final takeaways…

I think there is enough of a compelling use case in total capacity needed, and ultra-dense applications such as the stadium example, that 5G mmWave will be deployed commercially. But I’m still hedging my bets about the timing of 5G ubiquity. 4G, when aided by massive MIMO (Multiple In, Multiple Out), can achieve new heights of spectral density by using spatial multiplexing. Also, 4G wavelengths below 6GHz behave well compared to their unruly 5G counterparts.

But there’s one application I will be watching that no one mentioned- replacing the “last 200m” of fibre. Consider this. China has been witnessing a huge migration from the rural countryside to the big cities, a trend predicted to continue until 2035. There are dozens of mega-cities of about 10 million people each, where residents live in dense high-rise apartments. How does one bring internet to these residents without massive levels of new construction? One method would be to bring fibre to the intersection, and then use mmWave technology to connect to each household. The technical issues are massively reduced since this is a fixed communication application, not mobile. Dynamic searching and beamforming isn’t needed- the provider already knows the location of their clients. The beams can be fixed. Indeed, the first 5G trial from Verizon is a fixed point application. This video from Starry, an internet startup, shows how the company is using mmWave communication to compete against the ISP incumbents.

If you squint your eyes, between fixed point internet service, ultra-dense locations, and spectral scarcity, you can make the case for 5G. It’s not reality yet, but, it is the virtual reality.

In part three of this series I will look at the current state of the test industry in supporting 5G. In the meantime, readers, headset on!