eMTC and NB-IoT were both introduced simultaneously in Release 13
eMTC (enhanced machine-type communication) is a type of LTE-M network published by 3GPP in the Release 13 specification. eMTC is a low power wide area technology which supports IoT through lower device complexity and provides extended coverage. eMTC is a sub-type of LTE-M network, although the two terms are often used interchangeably.
According to HB Radiofrequency, an Australian-based wireless technology company,Narrowband IoT (NB-IoT) is a 3GPP Release 13 feature that reuses various principles and building blocks of the LTE physical layer and higher protocol layers and defines a new Cat-NB1 UE. “The standard leverages a mobile operator’s existing LTE base stations permitting rapid time-to-market. NB-IoT has been designed to offer extended coverage compared to traditional networks through the use of an ultra-narrow bandwidth of only 180 kHz. In comparison to a conventional LTE deployment, NB-IoT offers an additional 20 dB of link budget, equating to roughly ten times the coverage of a normal base station. NB-IoT finds its place as a long range, very low data rate service for low cost, non-real-time applications.”
HB Radiofrequency noted that NB-IoT technology can be deployed in three modes:
-Within an existing LTE channel by utilising existing resource blocks
-Utilizing the unused resource blocks within a LTE carrier’s guard-band
-As a standalone service, utilising an entirely separate carrier.
According to Laird Communications, the focus with eMTC devices is on providing a venue for machine-to-machine type communication, which requires a higher data rate and more overall throughput than the very low usage sensor devices that occupy the bottom end of the IoT. “Currently, LTE Cat M1 supports around 1 Mbit/s up and down with a frequency bandwidth of around 1.4 MHz — and that bandwidth is important in the distinction between LTE Cat M1 and LTE Cat NB1.”
“The defining trait of NB-IoT devices is that “narrowband” component. NB-IoT is designed for intermittently communicating, lightweight, low data usage devices that make up most of the sensors in the IoT. By design, they don’t require a serial-like connection as is found in LTE Cat M1. Instead, these devices might only transmit a few times an hour, and when they do the data volume is low. This means there are lesser requirements for data rates, less demands for low latency, and as a result of these, frequency bandwidths can be narrower.”
Chinese firm Alibaba Cloud said in a blog post that both the eMTC and NB-IoT mobile IoT network standards have often competed and created confusion over their application scope. “In fact, both standards have distinct technical advantages and can work together, so there is no better choice. As a result, the competition is decided by who can reduce their module chip costs faster, who has a higher degree of commercialization, and whose network construction is better. This issue finally got resolved in June 2017, when the plenary meeting of the 3GPP issued Release 15 representing a consensus on the future evolution of mobile IoT technology (including NB-IoT and eMTC).”
The Chinese company noted that Release 15 stated that future systems with a bandwidth under 1.4 MHz would not use eMTC terminals and future systems with a bandwidth over 200 KHz would not use NB-IoT terminals.
“This 3GPP resolution promoted the orderly development of M-IoT by clearly delineating the application scopes of eMTC and NB-IoT. Thus, the two standards are no longer in competition but form a hybrid network with differentiated and complementary cooperation.
Talking about the technical features of eMTC and NB-IoT, Alibaba Cloud highlighted that NB-IoT only supports data speeds under 200 Kbit/s, while eMTC can reach 1 Mbit/s. Regarding portability, because NB-IoT does not support automatic zone switching, terminals that use this standard are not portable. eMTC provides much better portability.
“In terms of voice functionality, NB-IoT does not support voice transmission, while eMTC does. Comparing zone capacities, we have seen that eMTC has not advanced in this direction, so it cannot satisfy the needs of high connection volume scenarios. In contrast, NB-IoT offers a coverage radius 30% larger than eMTC. eMTC’s coverage is about 9 dB below NB-IoT,” Alibaba Cloud said.
