What is LTE-M? The Most Important Questions and Answers

Mobile, economical and high-coverage, LTE-M provides ideal conditions for many IoT scenarios. We answer the most important questions about the mobile communications standard.

Connecting mobile objects over long distances presents enterprises with a wide range of challenges. Without the right network technology, connections can quickly be interrupted, making tracking more difficult or, in the worst case, impossible. That is why, if they want to track their shipments over longer distances, they rely on LTE-M. Using LTE-M technology they can equip their freight or other items with inexpensive sensors and keep track of their assets 24/7. Depending on the model and the scenario, an LTE-M module can function for five to ten years without a change of battery. LTE-M stands for Long Term Evolution for Machines and is a mobile communications standard that is ideally suited for connecting devices in special IoT scenarios. It is a Low Power Wide Area Network (LPWAN) standard that combines very wide network coverage and relatively low energy consumption. LTE-M was specially developed for IoT solutions for which NB-IoT can deliver neither the mobility nor the speed of transmission required but for which LTE would be too overdimensioned and too expensive. LTE-M bridges the two technologies.

As LTE-M modules, like cellphones, can switch from one cell to the next without having to reconnect, LTE-M is especially suitable for scenarios that involve tracking or monitoring position data. The logistics group Dachser, for example, connects its swap bodies by means of LTE-M wireless modules so that it can see their exact position at all times.  Deutsche Bahn has optimized its “Call a Bike” hire service by means of LTE-M. The data specialists at divirod have equipped their water sensors with LTE-M SIM cards to set up a flood disaster early warning system. And the startup Sharemac uses LTE-M to monitor machinery and equipment on construction sites.

IoT solutions exist in many different versions with highly variable data transmission, network coverage and mobility requirements. That is why companies need individual wireless solutions which best meet their specific needs. The ordinary LTE standard is used when very high bandwidths and low latencies are required. That can be in connection with Industry 4.0, especially applications based on Industrial IoT (IIoT), a technology that companies use to, inter alia, ensure that remotely controlled robots respond without delay in production or that video surveillance images appear promptly on security personnel screens.

The high performance of these modules has its price, of course, and LTE is less suitable for low-cost connection of remote sensor constellations. If in these scenarios a certain bandwidth and response capability is required, implementation with LTE-M technology can be significantly less expensive, especially for use cases in which a better building penetration is needed than standard LTE can provide.

If latency, bandwidth and mobility play only a minor role, the NarrowBand IoT (NB-IoT) machine and sensor network is a low-cost alternative with which to implement more extensive networking projects. That makes it highly attractive for use in, say, Smart City projects. With NB-IoT smart street lighting, sensor-based parking space monitoring or early warning systems for damage to traffic infrastructure are definite possibilities.

LTE-M is always an option when a compromise between LTE and NB-IoT is required. It provides higher bandwidths and lower latencies than NB-IoT without the high cost or energy consumption of conventional LTE solutions. In contrast to NB-IoT, LTE-M can also be used across borders if roaming in neighboring networks is activated. That is the case between Germany, France and Belgium, for example.

Because LTE-M is a globally standardized technology in the licensed mobile communications spectrum, it provides a high level of security for all applications: one that is based on the 3GPP-LTE security mechanisms. It is a higher level than proprietary technologies offer because the security mechanisms in LTE-M scenarios cover all aspects, from SIM cards to application servers. When the LTE-M network is accessed, both devices and network are checked precisely. Mutual infrastructure authentication is via the SIM card, on which sensitive logon information and device data are stored and protected from unauthorized access. The integrity of data transmitted is ensured independently of the encryption function by means of a specially generated key. Compared with other technologies, LTE-M uses longer keys (typically 128 Bit) to increase security. Data manipulation is reliably identifiable for both the device and the network.

LTE-M is based on the LTE-3GPP standard and is thus 5G-compatible, enabling users to position their IoT solutions securely for the future. LTE-M can also run more efficiently, saving more energy, with the nuSIM, a SIM card specially developed for IoT use. With this solution the SIM card’s functionalities are directly integrated into the chip and thereby consume up to 90 percent less electricity. In addition, LTE-M has countrywide network coverage in Germany and the Netherlands and the technology is in preparation or undergoing specific trials in many neighboring countries.