4G shalt thou not count, neither count thou 2G

Five years from now, what will be the leading mobile connectivity standard? If you said 4G, please report to the brainwashing remediation center nearest you immediately. 3G is not only here to stay for the long haul, it’s growing – and will quickly become the preferred choice for M2M deployments.

4G is a fantastic technology for smartphones, but it is overkill for M2M applications that generally don’t resemble streaming multimedia; more often than not, devices send short bursts of intermittent data on M2M networks. However, M2M is still drawn to cellular technology because it offers seamless mobility. Wi-Fi doesn’t work very well for applications that must work on the move – there may be coverage, but leaving the 100m or so radius where a connection was set up means setting up a whole new connection. Regional TV white space coverage is years away from resembling the broad reach of nationwide mobile network coverage.

From the other direction, 2G is waning, even though on a per-device basis it is plenty fast enough for M2M needs. AT&T has a site dedicated to getting M2M users off its 2G network, which it plans to retire by 2017. They cite spectrum efficiency – with UMTS/HSPA ranging from five to ten times better than GPRS – and the stunning growth in numbers of M2M devices creating deficit issues.

And no, small cells don’t fix a deficit problem – they fix signal strength and coverage issues, and help subdivide towers where there is still spectrum left in the neighborhood. Once spectrum is saturated in a dense area, that’s it; the choices are then to get more spectrum, get more efficient encoding, or get fewer devices connecting simultaneously. The number of M2M devices isn’t going to shrink anytime soon, 4G spectrum is precious and expensive, and the build out of smartphone networks for even more users continues globally. This leads to a Cisco projection, all from the Visual Networking Index 2014 mobile forecast update:

This all makes the case for designers of M2M networks and devices flocking to 3G en masse. Just as carriers warmed up to Wi-Fi offload as a way to ease their spectrum and infrastructure crunch, they will also be encouraging and incenting 3G use for M2M networks to keep their 4G spectrum and pipes clear for smartphone subscribers.

Considering just M2M connections, which includes emerging categories such as wearables with a cellular connection, Cisco says the balance shifts to over half 3G technology in the next five years. (An interesting point here: only 13 percent of wearables are expected to have embedded cellular connectivity by 2018, but most will still connect via a smartphone.)

What are the implications for semiconductor IP? The majority of M2M devices will not be on the bleeding edge – so don’t chase it thinking everything is headed there. “Yeah, but 5G will come, and M2M connectivity will then rotate to 4G.” I wouldn’t be so sure about that, at least on the same general beat of a decade between prior technology transitions.

The move to 4G was motivated by ARPU and getting more users on smartphones consuming more data – done, the value of a human user to a carrier has doubled since 2011. Without a similar data rate increase as seen from 3G to 4G, hard to achieve given available spectrum, there is no burning platform pushing carriers to undertake a 5G build out. Plus, we haven’t nearly tapped the full potential of LTE Advanced carrier aggregation and other features, or deployed enough devices worldwide to saturate growth.

Getting the most out of a device will mean a much more agile DSP core – such as the CEVA-XC family – that can deal with not only multiple carrier standards worldwide, but differing types of data traffic, all shrunk into tinier and tinier modules using less and less power. The M2M modules we see today from suppliers like Gemalto, Telit, Sierra Wireless, SimCom, and others already carry DSP-enabled SoCs. The trend will be toward software defined radios for M2M combining 3G cellular, Wi-Fi, and perhaps TV white space RAN support inside.

It’s a bit counterintuitive for technologists to think they won’t move to the most advanced standard just entering the mainstream, instead opting for the previous generation. For large M2M networks to succeed, we need to embrace 3G as the now and future connection.

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