MediaTek, China Mobile, crack on with NB-IoT enhancements

MediaTek has announced that it has wrapped up testing enhancements to its NB-IoT lineup of SoCs, in partnership with China Mobile. As it stands, it looks like NB-IoT is going to flourish in China, with the region set to be its strongest market. That suits Huawei, its main proponent, and MediaTek (a rival to Huawei’s HiSilicon) just fine, in a market that is now looking to get more out of NB-IoT.

Both LTE-M and NB-IoT were put forward as part of Release 13 of the 3GPP’s standards process – the long overdue low-power variant of LTE that had not been prioritized while the ecosystem raced itself to higher speeds. Initially called LTE Cat-M1 and Cat-M2 (respectively), the two approaches had been designed for machines through and through, as pure IoT protocols.

NB-IoT stems from a small company called Neul, which was acquired by Huawei, which in turn was the main advocate for the protocol. The variant that became LTE-M stemmed from a joint proposal from Nokia, Intel, and Ericsson – and so there were battle-lines (of sorts) drawn in the low-power LTE camp.

But the two protocols made it into Release 13, which itself was a bit late. There had been a gap in the market that the unlicensed LPWAN community was keen to exploit, where the likes of LoRa and Sigfox could provide the low-power connectivity to enable all manner of IoT applications, while the cellular community looked on and floundered for a couple of years. However, that scenario didn’t really transpire, for a number of reasons, and the cellular community, driven by the GSMA, is now pushing forward – big time.

So on one hand, the licensed spectrum community is gearing up for a push, but on the other, we see that the unlicensed options have not secured the path to billion-unit scales that they might have done. It seems that the licensed options have weathered the storm, and while it’s unfair to say that the unlicensed ones have now lost, it seems that the vision of huge volumes of LPWAN devices is going to be dominated by the GSMA ecosystem – even if the unlicensed variants are perfectly viable, they lack the scale and market power of the incumbent MNOs.

This latest announcement from MediaTek is a turning of the screw. NB-IoT is the protocol most likely to steal the thunder from LoRa and Sigfox, as it is fundamentally different from LTE. It doesn’t support voice, for example, and does not handle cell-handover particularly quickly, making it unsuitable for IoT devices like wearables or real-time asset tracking. It seems best placed in applications like smart metering.

For some time, we have understood that LTE-M and NB-IoT were too power hungry for use in applications like metering – where a device might need to be buried underground and achieve a ten-year battery life, in order to justify the business model. But it seems that the ecosystem has recently turned a collective corner.

Sierra Wireless and KDDI announced that they had partnered on a Japanese smart gas metering project, back in March, using a module based on Altair’s ALT1250 chipset to provide LTE-M connectivity. The pair claim that battery lives of ten years were enabled by the approach, which was a big step forward for the cellular community when it comes to metering – as that ten-year threshold is often considered a viability benchmark.

MediaTek is claiming a 4x to 6x increase on the data rate of the Release 13 standard, hitting an upload of 150kbps and a download of 100kbps. Crucially, MediaTek says this is now sufficient to provide firmware OTA updates (FOTA). These relatively large downloads, which might contain crucial updates to the device’s code, would use up a significant amount of the on-board battery in a device, meaning that a FOTA download could take years off of a deployment’s expected lifetime.

To this point, the prevailing wisdom has been to use a dual-mode design that can shift to LTE-M if it needed to download firmware – speeding through the download much quicker, spending less time on air, and ultimately, saving a relatively huge amount of battery life.

The other main claim is that it can enable voice-over-message (essentially VoIP), although it isn’t clear what is currently driving demand for such capabilities. MediaTek says it has also improved its positioning, multicasting, and multi-carrier techniques – which sounds like MediaTek positioning its NB-IoT offerings as viable alternatives to LTE-M.

MediaTek says that the key to these new abilities was the larger maximum 2536 bit Transport Block Size (TBS – the data payload plus its MAC address header), and 2 HARQ processes (Hybrid Automatic Repeat Request, a form of forward error correction plus ARQ acknowledgements).

The two current Release 14 MediaTek offerings are the MT2625 (single-mode NB-IoT) and the MT2621 (dual-mode GSM+NB-IoT). The former was the basis of what MediaTek and China Mobile said was the smallest NB-IoT module on the market, at 16mm x 18mm. The pair say that they will continue their interoperability testing, sharing the lessons learned on both the hardware and networking sides. They add that they will expand their efforts too – to promote the IoT.

“MediaTek is very pleased to be the first chip maker to pass the China Mobile NB-IoT R14 interoperability tests,” said Jerry Yu, MediaTek VP and GM of the Intelligent Devices business unit. “MediaTek is a key player in the development of the IoT standard and we are also actively developing the technology along with the industry. Currently, we have two R14-ready chips available, which will be widely used in the industrial and consumer IoT markets to usher-in the influx of the IoT era.”