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.

Rental bikes, swap bodies, construction machinery – when companies need to reliably network mobile objects over long distances and possibly across national borders, this brings a wide range of challenges. Without the appropriate network technology, connection interruptions can occur quickly, making tracking difficult or, in the worst case, even impossible.  

The Internet of Things (IoT) offers a solution here: For example, if freight forwarders want to track the route of their shipments over long distances, the IoT mobile communication standard LTE-M is a suitable option. LTE-M stands for “Long Term Evolution for Machines” and is ideal for networking devices in specific IoT scenarios. The standard is one of the so-called “Low Power Wide Area Networks” (LPWAN), which are especially convincing due to their very high network coverage with low energy consumption. LTE-M was developed specifically for IoT solutions where LTE would be oversized and thus expensive, while the alternative NarrowBand IoT (NB-IoT) cannot provide the required mobility or bandwidth for data transmission. The standard bridges the gap between the two technologies. Based on LTE-M, freight forwarders can equip their cargo with low-cost sensors and track the assets at any time via the IoT network. Depending on the design and application scenario, an LTE-M module can operate for five to ten years without a battery change.

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 syniotec uses LTE-M to monitor machinery and equipment on construction sites.

IoT solutions come in many different versions with highly variable data transmission, network coverage and mobility requirements. That's 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 only 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 standardised 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 therefore 5G-compatible – users can thus future-proof their IoT solutions with this technology. 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, reducing power consumption by up to 90 percent. 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.