This piece by Jörg Köpp, Market Segment Manager at Rohde & Schwarz explores emerging IoT trends in cellular networking and other communications.
Over the last couple of years, the cellular IoT (C-IoT) ecosystem and especially the 3GPP standardisation has focused on enabling the massive machine type communication (mMTC) market for applications such as water metering, cow monitoring, smart parking or asset tracking. The base technologies NB-IoT (Cat-NB1/2) and eMTC (Cat-M) were developed in Rel. 13/14, with dedicated features for very low power consumption (eDRX, PSM) and coverage enhancements (CE modes).
In the meantime, around 140 mobile operators around the world have deployed LTE M or NB-IoT networks, and the Global mobile Suppliers Association (GSA) has counted more than 500 devices supporting either Cat-M1, Cat-NB1 or Cat-NB2.
Emerging IoT applications in several industries as well as the global phase out of 2G and 3G networks drive the need for more application-specific extensions. Therefore, 3GPP is continuously working on improvements for NB-IoT and eMTC to cover specific application demands (Figure 1). Examples are features like wake-up signal or early data transmission, as introduced in Rel. 15. Both help to further optimise power consumption and reaction times. But in the long term, there is a need for a smooth transition to the era of 5G.
C-IoT in the era of 5G
5G was the first mobile network generation designed from the beginning to support not only the mobile broadband market (eMBB) but also the growing IoT market. Already in the first 5G release, the foundation was laid for the transition of mMTC (NB-IoT/eMTC) from 4G to 5G and for very low latency and ultra-reliable communication (URLLC) features as demanded, for example, by factory automation. 5G NR characteristics such as very flexible numerology, wide frequency support, built-in security and several layers of virtualisation create the base to support the essential 5G use case scenarios: eMBB, mMTC and URLCC (enhanced mobile broadband, massive machine-type communication, and ultra-reliable low-latency communication).
Essential for the future of mMTC in the 5G era are two factors: The coexistence of NB-IoT and eMTC in 5G thanks to very flexible use of radio resources; and the support of related features by the 5G core. Coexistence features as specified in Rel. 16 will allow 5G capable NB-IoT and eMTC devices to connect to standalone 5G network.
The Industrial IoT
Factories of the future will rely on deep integration of information and automation, enabled by ubiquitous connectivity. Therefore, the industry is looking for a very reliable and secure wireless communication technology that can be used for different applications on the factory floor. There might be alternatives to address one or the other case, but only 5G has the potential to address them all:
- 5G mMTC optimised for low power and deep coverage will be a strong fit for the tracking of tools and goods, or connecting sensors.
- 5G eMBB optimised for mobility and high data throughput will suit the task of connecting VR glasses and handhelds used by workers.
- 5G URLCC with the new features developed for in Rel.16/17 will enable full automation for controlling robots or automated guided vehicles.
URLCC is a completely new application area for cellular communication with very explicit requirements regarding latency, timing and reliability. 3GPP has spent reasonable efforts to address these requirements and now provides a comprehensive URLCC toolset.
It will help optimise the latency on the radio interface, thanks to features such as short symbol time and mini slots, together with enhancements such as fast and flexible repetition process, or grant-free uplink transmission. Network virtualisation, traffic prioritisation and multi-access edge computing will largely improve the end-to-end latency. The communication reliability can be improved by applying robust coding schemes, packet duplication and repetition as well as dual connectivity schemes.
This toolset also includes the support of time sensitive networks (TSNs) or LAN-type services via 5G, as mainly developed in Rel.16. Further improvements for time synchronisation or operation in unlicensed environment are in development in Rel.17.
Besides latency and communication reliability, network availability and security are of utmost importance for mission and business-critical applications in the industrial environment. Therefore, the industry has been looking to operate private 5G networks that could be deployed as stand-alone non-public network (NPNs) using private spectrum or public-network-integrated NPNs using network virtualisation as specified in Rel.16.
The comprehensive feature set of 5G adequately addresses a wide range of IoT applications, such as for extreme low cost, extreme low power and limited mobility with NB-IoT. But there are plenty of IoT applications like children’s safety wearables that would need long battery lifetime, very good coverage, but in conjunction with full mobility and reasonable data rates.
Other examples are emergency sensors that need extreme coverage, but also very low latency and low power consumption. In order to address these mid-range IoT applications, 3GPP started to study the application requirements under the name NR Light and is now in Rel. 17 going to standardise a new reduced capability (RedCap) device type with the focus on the typical requirements of industrial sensors, smart wearables and surveillance cams (Figure 2).
Non-terrestrial networks (NTNs)
Mobile networks as of today can cover more than 80% of the global population but only 40% of the land surface and less than 20% of the Earth’s surface. The only worthy alternative to addressing IoT applications of global sensing, tracking and monitoring is the use of non-terrestrial networks by using, for example, tiny low earth orbit (LEO) satellites. In Rel. 17, 3GPP is working on the integration of satellite components in the 5G NR architecture in general and studies initially the use of LTE based NB-IoT and eMTC via NTN.
The power of testing
3GPP is continuously driving the standardisation to meet today’s and tomorrow’s requirements for the IoT ecosystem. The large diversity of features and network scenarios, together with very specific IoT application requirements, will accelerate the demand for test and certification over the complete lifecycle of devices and network components.
With the rising number of business- and mission-critical applications using cellular technologies, testing aspects such as latency, reliability and power consumption becomes increasingly important. The continuous monitoring of networks in terms of performance, quality, security over all network layers – from the RF spectrum to the application – become essential.