The Mioty Alliance, set up to challenge the existing big four low power WAN protocols, has gained semiconductor firm STMicro as a member but still needs to attract more big technology companies to really threaten the established order. The Mioty protocol does though score by addressing shortcomings of the existing protocols while attempting to cater for a wider variety of IoT applications or use cases, including environmental monitoring and smart metering.
In particular, Mioty benefits from being based on the recently introduced narrowband TS-UNB specification from the European Telecommunications Standards Institute (ETSI), developed as a replacement for the Wireless Meter Bus (M-Bus) standard that has been widely deployed for smart metering in Europe, as well as some countries of Asia and Latin America. TS-UNB splits data packets into smaller sub-packets at the sensor level to improve wireless transmission performance and resilience.
The principle is similar to the splitting of single wideband carriers into multiple more slowly modulated narrowband signals under orthogonal frequency-division multiplexing (OFDM), which again increases resilience against interference and signal degradation on the basis of not putting all eggs in one basket.
In the case of the Telegram Splitting Multiple Access (TSMA) method, otherwise known as ETSI TS 103 357, the sub-packets are transmitted over different frequencies and time. An algorithm in the base station scans the spectrum continuously for mioty sub-packets and reassembles them into a complete message. Forward Error Correction (FEC) is employed to build in redundancy without need for retransmissions, with the receiver only needing 50% of the radio bursts to reconstruct the information completely. This reduces the impact of corrupted or lost bursts due to collisions and increases the resistance to interference that has dogged some implementations of the other LP WAN protocols.
There are four other main contenders – the two cellular options, NB IoT and LTE-M, mostly for licensed networks, alongside the proprietary LoRa and Sigfox for unlicensed spectrum.
LoRa offers relatively good bandwidth compared to other LPWAN technologies but is proprietary at the physical layer and requires chips from Semtech, the French semiconductor company that acquired the technology in 2012. LoRa has gained considerable momentum Europe but has failed to make the same impact elsewhere, especially North America. It requires its own network infrastructure, confining it to projects such as smart metering and some monitoring applications that lie within clear physical boundaries. However, that constraint also applies to Mioty.
This limitation does not apply to Sigfox, despite the technology also coming from a French company of the same name. The main constraint here is that Sigfox requires a cellular network to carry the signal, but then that is almost inevitable for the wider applications it is targeting, such as tracking containers like as smart trash cans or even suitcases. It is best for such applications where only extremely low bandwidth is available and energy is highly constrained, using self-contained transmitters that do not need an external power supply.
Although ranking fourth among these protocols on most counts, it does cover about 5.8m square kilometers, about two-thirds the size of the USA, reaching potentially 1.3bn people. It has gained ground through partnerships with major semiconductor companies, including Texas Instruments, Silicon Labs and ON Semiconductor.
Of the cellular options, NB-IoT was defined most recently early in 2016, aiming for low bandwidth, low cost and long battery life, but unlike Sigfox focusing almost exclusively on static indoor applications, especially where frequent transmissions are generated. It is confined to a single narrow-band of 200 KHz and uses OFDM modulation for downlink communication.
LTE-M is a heavier duty protocol that incorporates eMTC (enhanced Machine Type Communication), supporting higher data rates, mobility, and also voice over the network. But this requires more bandwidth and increased device cost. It still aims to minimize power consumption and enable battery lifetimes of 10 years in the field. Pilots from operators including AT&T, KPN, Orange, Telefónica, Telstra and Verizon have embraced wearable devices, asset management, smart shelving, logistics and some automotive deployments that do not require high capacity or ultra-low latency.
The MIOTY software itself was developed by the German Fraunhofer Institute, with those methods that increase signal resilience while minimizing the self-interference that can compromise such schemes, allowing up to 1m transmitters in principle. This increases range by about 10 times against conventional wireless systems in that same 868 MHz band.
STMicro insists this wide range as well as high performance will open up new use cases where Mioty will be deployed, rather than necessarily ousting the other protocols from the niches they have already colonized. The Mioty alliance claims data packets can travel several kilometers in built-up areas and over 15kms with line of sight, which would allow a few base stations to cover large industrial sites or outdoor areas. Another bonus is support for fast moving devices at up to 120km per hour (75mph) without signal fading, serving fleet management and asset tracking, although not perhaps high speed train travel.
As Hakim Jaafar, wireless marketing director at STMicro, said: “Mioty promises to make exciting new massive IoT applications possible, for instance, to cover large geographical areas. The Mioty stack further strengthens the ecosystem around our STM32WL SoC, which supports common sub-GHz LPWA technologies such as LoRaWAN, Sigfox, and wireless M-Bus, and delivers a unique level of integration that saves space, power, and time to market.”
Perhaps the biggest challenge for the Mioty Alliance is still to extend its reach in the other sense of attracting new members, especially beyond Germany. It is still dominated by its founders, Integrated Circuits IIS, Diehl Metering, Diehl Connectivity Solutions, ifm, Ragsol, Stackforce, and Wika in addition to the Fraunhofer Institute.
There have been a few recruits along the way, such as German radio assembly maker BehrTech. Beyond Germany we have had Canadian wireless IoT software company Weptech joining up, as well as most recently Swedish wireless sensor vendor Wittra in February 2021. The recruitment of STMicro, a pan-European company, is certainly a bigger step forward.