Internet of Things (IoT) via Satellite

Wireless data transmission systems are being increasingly deployed in industrial and home automation applications. These robust systems are used to transmit sensor data and control information across network infrastructures. In the age of the Internet of Things (IoT), people and things will be intelligently connected to one another, leading to innovations in business and Industry 4.0.

While the majority of IoT networks is terrestrial, IoT applications also provide various opportunities for established and newfound satellite operators, especially in connecting remote areas that lack terrestrial infrastructure. Opportunities range from selling additional capacity on GEO (geostationary) satellites in C-, Ku- and Ka-band for direct or backhaul connectivity to deploying new LEO (low earth orbit) or HEO (highly elliptical orbit) constellations, optimized for the IoT market.

Our solutions and IP (intellectual property) address many of the technical challenges in IoT communication, both terrestrially and via satellite.

IoT via satellite – use cases

IoT in LEO/HEO constellations

IoT in LEO/HEO constellations
© Fraunhofer IIS

LEO and certain HEO constellations operate much closer to Earth than GEO satellites. Therefore, there is less path loss and thus less terminal power and antenna directivity is required to close the link. This is advantageous in terms of terminal cost and size. However, LEO and HEO constellations come with the drawback of moving satellites, causing a highly time variant communication channel and the need for steerable antennas. Thus, an IoT terminal operating in a LEO or HEO network requires both a waveform tailored for the specifics of this communication channel and a suitable antenna design.

IoT using GEO satellites

 GEO satellites for IoT applications
© Fraunhofer IIS

Existing GEO satellites provide terabits per second of capacity worldwide, mainly used for direct-to-home broadcast and internet via satellite. The challenge for using such GEO satellites in IoT applications is the large path loss between earth and satellite and the slotted nature of the GEO orbit. This results in the need for rather large terminal antennas, with enough gain to close the link and with sufficient directivity to avoid interference into adjacent satellites and systems. IoT applications, on the other hand, typically require low cost and small size terminals and should not necessitate any manual pointing towards a satellite.

Hybrid terrestrial-satellite systems

Hybrid systems for terrestrial or satellite-based communication
© Fraunhofer IIS

Whenever the number of IoT devices in a given network or application is high, controlling the cost per device is of essence for commercial success. For such a scenario, hybrid systems using many low cost terrestrial-only IoT devices in combination with few satellite-connected aggregation terminals are worth considering. Use of terrestrial-only IoT technology allows meeting the cost point while the few satellite-connected aggregation terminals provide ubiquitous connectivity. Designers of such systems need to understand both terrestrial IoT and satellite communication, to mix and match the best of both worlds.

Solutions and intellectual property

Direct satellite connections for “Massive IoT” applications

Until now, terrestrial IoT base stations have often been used for data transmission of individual IoT devices to collect data and transport it to the internet. What works easily in well-connected regions becomes a challenge in remote locations with poor communications infrastructure. Often, the environment is not suitable for the construction of base stations, or it is financially not feasible to provide enough base stations for a complete coverage.

A globally available satellite network offers the solution: instead of sending data via permanently installed base stations, IoT devices transmit directly to the satellite. This allows each device to communicate with the satellite from anywhere in the world without relying on terrestrial IoT networks.

As a result, a large number of IoT devices are located in the satellite's coverage area. For data transmission, an appropriate transmission protocol is required to ensure high system capacity. Our IoT technology mioty® is ideally suited for this, as it can send data packets from many IoT devices simultaneously over long distances. It is particularly energy-efficient, resistant to interference, and guarantees high system capacity. mioty® can also be used via satellite without adapting the radio protocol, enabling direct data transmission to the satellite.

Hybrid systems for terrestrial or satellite-based communication

Hybrid terrestrial-satellite systems require both in-depth understanding of terrestrial IoT and satellite communication. While it may appear attractive to use the same technology and waveforms for terrestrial and satellite communication, competing requirements and technical constraints – low power and low cost terrestrial communication in “unlicensed” bands below 1 GHz vs. PSD constraint and highly regulated satellite communication at frequencies above 10 GHz – favor a hybrid solution, optimized for “terrestrial” and “satellite”.

In addition to satellite communication, Fraunhofer IIS is also heavily engaged in providing technology, intellectual property and solutions for terrestrial IoT networks. This includes wireless sensor networks using s-net® technology and the wireless IoT solution mioty®. 

Efficient data processing on site

In IoT applications, often every minute is critical when time-sensitive information is transmitted via satellite and rapid responses are required. Small amounts of data can be transmitted quickly and easily, but with large data sets, transmission can become problematic: as the data volume increases, so does the transmission time.

Therefore, with our fully automated and self-regulating IoT systems, we span an ad-hoc network in which individual IoT devices can exchange and pool their computing power. The raw data collected is processed directly on-site using Artificial Intelligence and compressed to relevant information. The reduced amount of data can now be transmitted easily. In addition, not all IoT devices need to communicate with the satellite anymore, as a single device can transmit the calculation result.

Extreme Edge Computing offers significant advantages for Sat-IoT applications in terms of:

  • Fast data transmission, as the processed data can be easily transmitted in combination with our mioty® protocol.
  • Low latency on site, as distributed computing allows large amounts of data to be evaluated directly in the field. The result is immediately available locally.
  • Energy efficiency, as the battery of the mobile IoT devices benefits from distributed computing and has a longer service life.

High-performance IoT antennas for satellite communications

IoT devices need antennas with sufficient performance to bridge the distance between transmitter and receiver. Given the distance of several 100 kilometers between Earth and LEO satellites and up to 40000 kilometer to GEO satellites, such antenna designs are considerably challenging.

Size and complexity constraints prohibit the use of mechanically steerable reflectors or larger electronically steerable phased arrays for “Massive IoT” applications. Fortunately, compared to High-Throughput Satellite (HTS) that offer Internet services, throughput requirements for IoT are comparably low. This allows using small antenna apertures that provide adequate gain and beam steering capabilities while keeping antenna size, number of radiating elements and complexity of the excitation network low.

Fraunhofer IIS offers different antenna solutions for this use case, including

  • Higher order mode patches with directivity optimized for modest elevation angles
  • Multibeam antennas with several alternative pre-defined beam options
  • Compact phased arrays, with cost-optimized phase shifters and a wide range of beam synthesis options

Regulatory constraints for direct satellite connectivity

Considering “Massive IoT” applications over satellite, a large number of terrestrial terminals may concurrently transmit to the satellite. As these IoT terminals may share the same frequency band with other terminals transmitting to other satellites, care must be taken to ensure that the systems do not interfere with each other.

For most antennas, the beam width is indirectly proportional to the size of the antenna, i.e., a small footprint antenna has limited gain and directivity, thus produces a “wide” beam. This results in unwanted emissions toward adjacent satellites in the GEO orbit and other LEO or HEO satellites or terrestrial receivers. Therefore, to mitigate such harmful interference into other systems, direct-to-satellite IoT terminals need to comply with defined power spectral density (PSD) masks. Depending on beam width and pointing accuracy, such PSD masks significantly limit the permitted transmit power, link efficiency, system capacity and the number of IoT terminals in the network.

Fraunhofer IIS has devised a novel solution addressing the efficient use of spectrum and maximizing system capacity in such PSD limited scenarios, considering terminal and antenna type and pointing accuracy. Furthermore, a waveform implementing such concepts has been developed and is available in simulation.

Profit from our know-how

Thorough understanding of transmission technology, market needs and constraints of the target application is vital for the right selection of the features and for building a unique and successful IoT product. Thus, as an equipment or chipset manufacturer, as a network or satellite operator or as a IoT system integrator, benefit from our background and know-how in:

  • Waveforms and solutions for “Massive IoT” applications
  • Terrestrial-only and hybrid satellite-terrestrial systems
  • IoT antennas
  • End-to-end system design and optimization as well as consulting

A key advantage for many applications

Icon wildlife monitoring

Wildlife monitoring

Many animal swarms live in remote areas beyond the reach of terrestrial communication infrastructures. Data collected in these regions, for example using animal tags, can often only be transmitted to the nearest base station with a long delay of days or weeks. By connecting existing networks via satellite, global connectivity and faster data transmission can be ensured.

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Agriculture

In the field of agriculture, the use of IoT is no longer a vision of the future: in ground-based earth observation, IoT sensors are used in field soils. These provide important information about the soil condition, such as nutrient content or texture. The data is then relayed via satellite to the farmer or to connected agricultural machinery.

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Logistics

Placing IoT transmitters on trucks or containers makes real-time monitoring a reality in logistics. The transmitters continuously send their current location to a satellite. This means that goods routes can be tracked without interruption, even if, for example, a ship is moving hundreds of kilometers off the nearest coast. 

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Mining

In the mining industry, the Internet of Things is becoming more and more prevalent in the form of so-called smart mining. Both above ground and underground, small sensors are being used. While underground they track air conditions and the smallest changes in the ground to ensure the safety of employees. Above ground they enable real-time tracking and management of the necessary trucks and vehicles.

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