LTE-M and NB-IoT meet the 5G performance requirements
Connectivity is a foundation for the Internet of Things. As a result, the type of access required will depend on the nature of the application. The access technology characteristics span from Critical IoT, with high demands for reliability, availability and low latency, to Massive IoT for low-cost devices with low energy consumption and wide area coverage. Cellular technologies can serve both. In this blog post, we will explain how the radio access technologies standardized by 3GPP, with focus on Release 15, address the 5G massive IoT requirements.
We illustrate the outstanding performance of LTE for Machine-Type Communications (LTE-M) and Narrowband Internet of Things (NB-IoT) in terms of coverage and system capacity. We also highlight that LTE-M and NB-IoT can seamlessly coexist with 5G New Radio (NR) access technology.
LTE-M is the industry term used for the wide range of LTE features and the narrow bandwidth device category for the support of mMTC. NB-IoT is a narrowband radio access technology reusing components from LTE. Both technologies support high system capacity, energy efficient operation, ultra-low device complexity and ubiquitous coverage. Read more about LTE-M and NB-IoT in this earlier blog post.
The impressive performance of LTE-M and NB-IoT in combination with the ability to operate within an NR carrier establishes LTE-M and NB-IoT as the most prominent, and futureproof, Massive IoT technologies.
In Release 15, 3GPP performed a 5G self-evaluation of NR, LTE-M and NB-IoT performance. Our contribution to the evaluations show that LTE-M and NB-IoT both support the 5G connection density requirement of 1,000,000 connected devices per km2 with a service latency of at most 10 seconds.
Figure 1 presents the LTE-M and NB-IoT service latency as a function of the supported connection density per 180-kHz physical resource block (PRB) and km2. For the deployment scenario studied here, LTE-M and NB-IoT meet the requirement with approximately a single PRB. We also see that LTE-M offers optimized latency performance, while NB-IoT supports higher utilization of the available spectrum.
Figure 1: LTE-M and NB-IoT service latency as a function of the supported connection density.
As a part of the 5G self-evaluations, we have also studied coverage performance of LTE-M and NB-IoT. Our results show that both technologies can operate down to extreme signal-to-noise ratio (SNR) levels, providing a coupling loss between the base station and the device of 164 dB which matches the 5G coverage requirements.
For more information about the 5G requirements and evaluations refer to 3GPP Technical Reports 37.910 ‘Study on Self Evaluation towards IMT-2020 Submission’, and 38.913 'Study on scenarios and requirements for next generation access technologies'.
Mobile network operators should be able to support the above presented Massive IoT performance in combination with enhanced mobile broadband (eMBB) and Critical IoT use cases. To allow this, 3GPP Release 15 supports a close coexistence between NR, LTE-M and NB-IoT. The specifications allow the three technologies to:
- operate in the same frequency band,
- configure the same physical layer numerology, i.e. sub-carrier spacing,
- align the uplink and downlink transmissions in time and frequency, and,
- reserve NR time-frequency resources dedicated for LTE-M and NB-IoT transmissions.
Figure 2 illustrates the concept of LTE-M and NB-IoT operating within an NR carrier by means of reserving resources for their transmissions. For more information on coexistence between NR, LTE-M and NB-IoT check out the white paper NB IoT and LTE-M in the context of 5G industry.
Figure 2: NR, LTE-M and NB-IoT coexisting in the frequency band n8.
In summary, LTE-M and NB-IoT meet the IMT-2020 and 3GPP 5G requirements for Massive IoT and support seamless coexistence between NR, LTE-M and NB-IoT. This makes LTE-M and NB-IoT today’s most prominent and futureproof 5G Massive IoT technologies.
Ericsson has evaluated all aspects on LTE-M and NB-IoT performance. For a complete picture of the Massive IoT system capacity, link level data rate, latency and device battery life, please refer to our latest contributions to the 3GPP work, which you can download from the 3GPP web site: IMT-2020 self evaluation: mMTC non-full buffer connection density for LTE-MTC and NB-IoT and IMT-2020 self-evaluation: mMTC coverage, data rate, latency & battery life.