MIOTY plays resilience card in LPWAN game

by | Jul 21, 2020 | BLOG

Distant observers of the burgeoning IoT market and the associated LPWAN (low power WAN) protocols – for longer distance wireless communication in sub-GHz spectrum – might be mystified to observe another protocol clambering aboard with some serious backing. This is, after all, a congested field where heated battles are being fought already between five contenders for low power communications, across campuses, cities, and industrial parks in particular.

The new challenger is called MIOTY (a portmanteau of MY IOT) and is playing the robust-ness card against its rivals. Certainly, on cursory analysis, it looks better placed for providing near-guaranteed delivery of data packets under poor signal conditions with interference from obstacles or other radio communications in dense RF environments. It is also playing on scalability by transferring complexity to single central points, typically some base stations, where hardware can be expanded, while minimizing processing in the devices themselves.

Naturally, all the LPWAN standards have been designed to minimize computational bur-den in order to enable small form factors and batteries to last effectively for their full shelf life, up to 20 years. But having come along later, MIOTY has been optimized totally for low bit-rate communication across unreliable wireless networks, where error-free delivery matters more than latency or bit-rate.

Its key feature has echoes of adaptive bit-rate (ABR) streaming for online video delivery, where the data is split into chunks to optimize quality and bandwidth consumption across unmanaged IP packet networks, primarily the Internet. In the case of MIOTY, packets are split into smaller sub-packets at the sensor level, a relatively simple operation easily executed by a small processor.

These sub-packets are then transmitted at different frequencies and times as available, with some duplication for redundancy, arriving randomly and out of order from multiple clients at the central station. This station employs a sophisticated algorithm consuming considerable hardware resources scanning the spectrum for all MIOTY subpackets and re-assembling them into the complete messages.

This is based on an underlying ETSI specification called TS 103 357, or more informally telegram splitting, operating in the 868 MHz band, which is license-free in Europe, requiring just 200 KHz of bandwidth. The method was developed by Germany’s Fraunhofer Institute and licensed to Canadian firm BehrTech for global commercialization.

The duplication allows full recovery of the received data in the event of up to 50% of sub-packets being lost in transmission, far higher in practice than commonly used forward error correction (FEC) or packet re-transmission mechanisms.

This is certainly an improvement over the rival LPWAN mechanisms, but as we know from the history of communications, being the best technology is no guarantee of success, especially when others have already gained wide traction.

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