I've seen two things today that are trying to suggest that 5G (or even 4G) are going to cause problems for WiFi, or even "kill it".

Ignore them.

Firstly, this piece by Bloomberg (link) suggests that a combination of mobile operators' renewed flat-rate data plans, along with LTE-U, could render WiFi obsolete. It's one of the worst pieces of technology "journalism" I've read in ages.

Secondly a discussion on Twitter led to a 3GPP document about "New Services and Markets" from a year ago, which talks about "Mobile Broadband for Indoor Scenario" in section 5.5 (link). That seems to suggest that 4G/5G could replace office WiFi or even wired LANs.

Needless to say, both are total nonsense. There is a longstanding strain of thought among some "cellular fundamentalists" that WiFi is just a step away from being replaced by mobile operators' services. It is wishful thinking, verging on delusion. (It won't be subsumed as a mere secondary part of 5G, either - although that's a separate post).

While there are some corner-cases that might swing one way or the other, based on pricing and perhaps neutral-host cellular using LTE in unlicensed bands (perhaps in MuLTEfire guise rather than the anti-competitive LTE-U and LAA variants), those are rare exceptions.

In home, offices, and public spaces, there is essentially zero chance that owned WiFi or fixed ethernet are going to be replaced in large quantity, by 5G operators acting as LANaaS providers.

There are many reasons for this, but some of them are:

• Billions of WiFi-only devices, from PCs and tablets, to TVs, printers and a broad array of consumer and industrial products.

• Billions more WiFi-only devices in future (no, not everything will have a cellular module & eSIM - it's way more expensive and limiting - see my report link)

• The ability for WiFi to operate easily in "service", "subscription", "amenity", "owned", "free", "local", "sponsored", "venue-provided", "ad-supported" and many other business models. Cellular connectivity - reliant on SIM or eSIM - generally enshrines "subscription" and a service model as the only option.

• Ability of venue-owners to control and police WiFi network access (eg a cafe-owner or conference organiser can give the codes to their choice of user, under their conditions)

• Use of WiFi Direct for P2P connectivity

• Integration of WiFi in businesses with LAN and security systems

• Preferential use of WiFi in-built to smartphone OS's and connection-management tools

• Large % of people who are not using flat-rate mobile data plans, especially prepay users in most of the world

• A broad view that WiFi is not only "free" but also *different* as it isn't owned / metered / tracked by service providers. (You've all seen that revised Maslow pyramid with WiFi scrawled as a tier beneath food & shelter, I bet)

• Anonymity of most WiFi hotspots

• Huge push of WiFi by cable, fixed-broadband and some WiFi-first MVNO providers, including to outdoor / metropolitan zones and being built-into 500 million or more home gateways around the world

• Use of WiFi in public transport (buses, trains, planes) - even if backhauled by 4G and/or satellite, plus increasing use of WiFi hotspots in cars (again, linked via LTE to the network)

• Poor penetration of cellular for deep-inbuilding use without DAS or small cell coverage, which is often impractical

• Lower costs of infrastructure, especially given the heavy IPR load associated with 4G modems and base stations. 

• Enterprise desire to use multiple connections for cloud/WAN access, eg via SD-WAN

I think the most risible line in the Bloomberg piece is this "Wi-Fi also helps fill in gaps in some office buildings and homes that have spotty cellphone coverage" - in many ways, it's the complete opposite of the way many users view the two technologies.

Every analysis I've seen has suggested that WiFi use is generally growing faster than cellular data consumption, and there is very little reason to expect it to change. In many ways, I'd expect WiFi - and also other unlicensed band technologies for LPWAN and IoT - to outstrip coming cellular use-cases, especially indoors but also for the wide area.

A less-virulent strain of the same bad idea is that 5G will absorb or subsume WiFi, as part of its amazing network-slicing / HetNet / integrated architecture. That's wrong too - although some cellular networks are fairly-well integrated with some WiFi, there is a very large universe that isn't, and for many of the same reasons won't be in the future either. The notion that 5G is some sort of magical wireless umbrella (or Borg) that will assimilate all others is just a "mobile industry establishment" fantasy and lobbying hook.

One last thing I'd add - I'm seeing an increased amount of interest in the opposite to LTE-U and LAA - the idea of running WiFi in licensed bands, either with new forms of spectrum-sharing, or perhaps even with adventurous regulators looking at getting more usage out of existing spectrum. After all, if the technical work suggests that LTE-U doesn't compromise or interfere with WiFi, then the converse is true as well, especially at lower power in regions with no cellular coverage, or indoors.

Overall: Ignore any reports of WiFi's demise, or the ability of 4G/5G to replace it in the future. It's simply not going to happen, except in a couple of tiny overlaps on the big wireless Venn diagram. WiFi puts downward pricing pressure on cellular data - it's probably part of the reason for the return of flatrate data in the first place. It's also a prime example of "network diversity" which would be worthy of protection against creeping cellular "network monoculture", even if it wasn't already guaranteed a healthy future.