Narrowband IoT (NB-IoT) and LTE Machine Type Communications (LTE-M)—these are Low Power Wide Area technologies (LPWA) which utilises the radio access network for connecting devices with low bandwidth requirements whilst providing increased penetration with the added capability of using low power. The 3GPP released information concerning LTE-M and NB-IoT for Rel.13 in June 2016, known as CAT NB and CAT M or rather Category Narrowband and Category Machine Type respectively.
Technical comparison — There are various differences between NB-IoT and LTE-M for example the carrier bandwidth, throughput and coverage.
One of the main features concerning LPWA technologies is the enhanced coverage capability; for LTE-M the Maximum Coupling Loss (MCL) has an additional gain of approximately 10dB and 20dB for NB-IoT when compared to GSM.
This is achieved by a few factors:
- Repetition of transmissions
- New control channels (usage of Non Access Stratum)
- Size of UE bandwidth
For other field tests that were carried out for data delivery times and battery life, the results are shown here.
Device Ecosystem — The device architecture for LPWA devices does not differ much from the architecture of cellular devices. As an example, the following images outline the main elements of a typical smart meter. In the near term it will be possible to design host-less (app environment inside the chip – no external A-CPU required) for LPWA devices which allows more efficient (space usage, power consumption) hardware designs.
Use Cases — LPWA networks allow a wide range of opportunities, the evolved spectrum has introduced some new capabilities which allows a range of requirements to be addressed.
Some of the opportunities which LPWA enable.
NB-IoT and LTE-M have evolved as technologies which enable the connectivity of a range of devices, using the low power consumption capability with increased coverage footprint. It is obvious that for deeper coverage, whether underground or in a remote region far from any cellular site, NB-IoT outperforms LTE-M by ranges of approximately 10dB.
Also with NB-IoT, a device has a much longer battery life with around 15 years, while LTE-M is around 10 years. This longer battery life offered by NB-IoT reduces the number of maintenance inspections that such IoT devices would require, allowing for operational savings on expenses.
The modules that offer NB-IoT are generally cheaper and with costs of around half the price in most instances.
Currently NB-IoT has a larger global footprint than LTE-M, this can be attributed to the fact that where there are still 2G and LTE networks this in some ways reduces the need for LTE-M, whereas NB-IoT with itsm enhanced coverage capability provides a capability that these network technologies are not able to mimic.
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