Could LTE-M Torpedo NB-IoT?Could LTE-M Torpedo NB-IoT?

Like a North Korean missile, NB-IoT was launched to the accompaniment of much chest-thumping rhetoric only to hit problems soon after take-off. Several months since it emerged from the lab, the Internet of Things standard risks being knocked off course by interoperability problems and service providers' preference for the rival, unlicensed-spectrum technologies it was supposed to "crush." (See Ericsson, Huawei incompatibility threatens NB-IoT – sources and Vodafone to 'Crush' LoRa, Sigfox With NB-IoT.)

But could the biggest threat to NB-IoT come from another cellular technology? The LTE-M standard, which also formed a part of the 3GPP's Release 13 update last year, was never expected to be of much consequence outside North America, says Tom Rebbeck, a director at the Analysys Mason consulting and market-research group. Yet it has been quietly attracting interest in other parts of the world. A major commitment to the standard by an Asian heavyweight like China Mobile Ltd. (NYSE: CHL) could blow NB-IoT out of the market.

At least, says Rebbeck, it would "make the case harder for NB-IoT" as the globally preferred cellular standard for so-called "low-power, wide-area" (LPWA) connectivity. And if the short history of wireless communications tells us anything, it is surely that standards addressing the same opportunities rarely coexist in harmony. Battles ensue, and sooner or later the industry gravitates toward a single technology -- LTE rather than WiMax, for instance, or GSM over CDMA.

The momentum behind LTE-M is undeniable. As expected, both AT&T Inc. (NYSE: T) and Verizon Communications Inc. (NYSE: VZ) are backing it in the US. More surprising is the support that LTE-M has gained in Europe in the last year. Although NB-IoT is favored by industry giants including Germany's Deutsche Telekom AG (NYSE: DT) and UK-based Vodafone Group plc (NYSE: VOD), several big operators have swung behind LTE-M, including France's Orange (NYSE: FTE), Spain's Telefónica and KPN Telecom NV (NYSE: KPN) of the Netherlands. Both KPN and Orange are using LTE-M as a complement to LoRa, while neither has announced plans for NB-IoT. (See Verizon Takes IoT Network Nationwide, DT Claims World First on NB-IoT, Tier 1 Operators Back LTE-M, KPN to Include LTE-M in IoT Mix in 2017 and Eurobites: Orange Bangs the Drum for LTE-M.)

South Korea's SK Telecom (Nasdaq: SKM) is similarly following that approach of building an LPWA strategy around LoRa and LTE-M. LoRa, it previously told Light Reading, is ideal for "low-mobility" applications and transmitting small amounts of data over long distances. LTE-M, by contrast, is better for connected car services and others that are a bit hungrier for bandwidth. (See SK Telecom Sees LTE-M, LoRa as Its 'Two Main IoT Pillars'.)

If, from a pure technology perspective, NB-IoT's closest rivals are Sigfox and LoRa, then operators might be expected to use it alongside LTE-M in a similar, complementary fashion. That is certainly how the vendors are presenting it. "LTE-M is not a threat to NB-IoT -- it's actually complementary to NB-IoT," said a spokesperson for China's Huawei Technologies Co. Ltd. in comments emailed to Light Reading.

But Rebbeck disagrees. In his view, the growing appeal of LTE-M has led some operators to hold off making any commitments to NB-IoT. "The price difference between NB-IoT and LTE-M modules is marginal and there is not much difference in terms of battery performance," he tells Light Reading. "And the performance of LTE-M is a lot higher and might be more flexible for future applications."

Want to know more about the Internet of Things? Check out our dedicated IoT content channel here on Light Reading.

That sounds like a compelling reason for a service provider to consider using LTE-M instead of NB-IoT. And some operators evidently believe LTE-M can address opportunities often discussed in the context of NB-IoT, Sigfox and LoRa. Orange, for example, has been carrying out a pilot of smart electricity metering using LTE-M. Verizon says LTE-M can support "an array of use cases ranging from water meters to asset trackers to consumer electronics."

So perhaps, unlike SK Telecom, Orange has settled on LoRa and LTE-M not because they address radically different opportunities, but simply to make sure it has both licensed and unlicensed spectrum options in its LPWA arsenal. As a 3GPP-sanctioned standard, LTE-M runs over licensed spectrum bands, of course, while LoRa takes advantage of unlicensed frequencies. (Technically, it seems, there is nothing to prevent LoRa from being used in licensed spectrum bands, but existing equipment and regulations pose barriers to this move, Orange told Light Reading in December last year.) That would not appear to leave much room for NB-IoT. (See Is LoRa Going Licensed?)

NB-IoT is still very much alive and kicking, despite the challenges it faces. But the industry now looks at LTE-M far more approvingly than it did just a year ago, when, says Rebbeck, the technology seemed likely to be confined to North America. It has now gained supporters in Europe and the Far East, he says, while "the Chinese operators are playing around with [it]." A big commitment to LTE-M by the likes of China Mobile might spell further disappointment for NB-IoT.

— Iain Morris, , News Editor, Light Reading