By Claus Hetting, Wi-Fi NOW CEO & Chairman
So what will be role of Wi-Fi when (or if) the 5G train finally starts rolling? It’s a tricky question to answer, since 5G technology has yet to be fully specified. We’re taking a stab at it here and it’s definitely not our last word on the issue. Feel free to voice your opinions as you wish.
So what exactly is 5G?
The crux of future 5G is the so-called 5G NR standard, which is a new radio interface spec for mobile that builds on 4G but adds a pile of new features. Of these the most important might be ‘massive MIMO’, which could add a lot of capacity to mobile networks. Another part of 5G appears to be the incorporation of mmWave bands (28 GHz and up) for mobile or – more likely – FWA-type services.
None of this appears to be particularly revolutionary. As any wireless expert will tell you, there are only two ways of squeezing more capacity out of mobile radios: More spectrum or better spectral efficiency (more bits per Hz). Since 4G is already operating close to the Shannon limit, the massive MIMO option is pretty much what’s left, hence its inclusion into 5G.
To be fair, the 5G community also has a grand vision for a slew of new services for all kinds of verticals and special cases. Thus far we’ve not been able to identify anything concrete in any of these areas.
How FWA became a mobile technology
More spectrum will presumably come from the mmWave bands – although in the US, various other bands including 3.5 GHz are being pushed for 5G. Unfortunately, mmWave bands are impractical for building out mobile services in the traditional sense because of the beam-like physics involved. Hence the 5G community is touting FWA (Fixed Wireless Access) as a 5G application, even though FWA is not mobile – its fixed, as the name suggests.
So what does this have to do with Wi-Fi?
The short answer is not much. The 5G community is of course very well aware that Wi-Fi will continue to exist and continue to carry the brunt of mobile data plus all of the data on non-SIM devices.
Wi-Fi also addresses a huge number of enterprise, in-home, and IoT use cases that – let’s face it – mobile services have never successfully addressed. So the question is whether or not 5G will attempt to replace Wi-Fi, somehow find a way to interwork with Wi-Fi, or simply leave Wi-Fi alone – or a combination of any of those. Let’s address these in turn.
Will Wi-Fi be replaced by 5G?
The 5G folks are already touting traditional Wi-Fi strongholds as target markets for 5G, including in-home, stadiums, indoor high-density, enterprise applications, etc. There’s little doubt that the 3GPP will want to standardise unlicensed versions of 5G just as LTE-U/LAA and Multefire are unlicensed versions of 4G operating in the 5 GHz band today.
Thus far there has been little deployment of unlicensed 4G. And as far as we know, Multefire technology (the enterprise version of unlicensed LTE) has yet to be deployed. This does not bode well for 5G unlicensed. Our take is that the Wi-Fi ecosystem is five to ten years ahead of anything 4G or 5G in any of the enterprise segments that the 3GPP is eyeing right now.
Will 5G be made to interwork with Wi-Fi?
Interworking is mostly a core network issue, since it’s unlikely that IEEE and 5G radio standards will be harmonised. Interworking (call it offload if you like) already exists between 3G/4G and Wi-Fi, although the standards to support this have largely been a 3GPP afterthought.
Our best bet is that any 5G interworking with Wi-Fi is low priority and will arrive late. There’s a good chance that 3G/4G-type interworking with Wi-Fi on the core network side will be retained for now. It may eventually upgraded to support future 5G core networks.
Will 5G leave Wi-Fi alone?
In practice there’s a not a great deal that the 3GPP can do about Wi-Fi other than try to develop a competing technology. At best it will take the 3GPP years if not a decade or more to catch up. By that time, it will likely not be relevant any more.
What remains is the risk of regulatory intervention. Now there’s probably zero chance that 5 GHz bands would ever be taken away from Wi-Fi, and it appears that the mobile community is not particularly interested in the 6 GHz bands either given recent responses to the FCC NoI (read more here). Right now, regulatory risks appear low.
The ‘Swiss Army Knife of wireless’
The strength of Wi-Fi lies in its wide adaptability to myriads of use cases and not least the speed of Wi-Fi innovation. We like to think of Wi-Fi as the Swiss Army Knife of wireless: Wi-Fi is ready to take on a ton of new connectivity challenges – although a few essential tools might still be missing.
The service-oriented approach of 5G is the complete antithesis to Wi-Fi. For every use case, a fully baked 5G service needs to be made ready through the painstaking and time consuming 3GPP standardisation process. We believe the world has long since moved on from this approach.
‘It’s the economy, stupid’
The final question is whether today’s mobile industry is in a financial state to pursue a major technology upgrade. This is perhaps the most important question of all.
We believe that the most likely use case for 5G is as a slow and fairly sporadic evolution of LTE lumped in with a few FWA-style ‘5G’ cases. This will look nothing like the overhyped 5G vision pushed by vendors and tech media today. In the interim, we expect Wi-Fi and other unlicensed technologies to race ahead and capitalise on lots of new use cases, including IoT.
Also make sure you keep an eye out for spins on the ‘5G’ term. For clarification: The 5G we’re referring to here is the 3GPP-standardised version and not the various upgrades of LTE. Nor is 5G anything operating in the 60 GHz band, which is sometimes referred to as ‘5G’ even though it is (in every case we know of) of based on WiGig (802.11ad).
Standard disclaimer: Our view on this is still evolving as more information on 5G becomes available.