By Juan Pedro Tomás
Internet of Things (IoT) and Machine Type Communications (MTC) applications are experiencing an exponential surge and are expected to play a key role in future networks and systems. However, the industry is well aware that terrestrial networks alone will not be able to serve the key requirement of the IoT of a truly ubiquitous coverage. To fulfill with this requirement, several initiatives are currently addressing the inclusion of a satellite component into the telecommunication infrastructure to extend its coverage to those areas that are currently not served or underserved by the terrestrial networks.
One of the key initiatives in this field is the 3GPP study item on NB-IoT over Non-Terrestrial Networks (NTN). The study item will have the main goal of assessing the performance of the NB-IoT air interface over satellite and will identify which adaptations are required in order to enable a proper use of this technology.
According to a report by 5G Americas, IoT operations are critical in remote areas with low or no cellular connectivity for many different industries, including transportation (maritime, road, rail, air), logistics, oil & gas harvesting, utilities, farming, environment monitoring and mining, among others.
Non-terrestrial networks to complement terrestrial networks for IoT
The report noted that satellite networks can be used to complement to terrestrial network to provide IoT services for low or no coverage area. “3GPP has started a work item in Release-17 on NTN for NB IoT and eMTC. Its objective is to specify support of NB-IoT and eMTC over NTN with GNSS (Global Navigation Satellite System) capability in the UE taken as a working assumption for both NB-IoT and eMTC devices. NB-IoT/eMTC design for terrestrial networks will be reused as much as possible in this case,” 5G Americas said.
Swedish vendor Ericsson said in previous report that the NTN work in Rel-17 introduces new network topologies into the 3GPP specifications. “These topologies are based on high-altitude platforms and low Earth orbit (LEO) and geosynchronous orbit satellites. NTN complements terrestrial networks with network coverage in remote areas over sea and land where terrestrial coverage is absent,” Ericsson said. Ericsson also highlighted that the work done by the 3GPP addresses NR, Narrowband-Internet of Things (NB-IoT) and LTE for Machine Type Communication (LTE-M), and it will thereby facilitate 3GPP NTN-based MBB and massive IoT services from Rel-17 onwards. The European vendor also said that Rel-17 work builds on earlier studies performed in Rel-15 and Rel-16, where NTN channel models and necessary adaptations of the NR technology to support NTN were identified. Ericsson stated that the main challenges identified in Rel-16 and addressed in Rel-17 are related to the mobility and orbital height of the satellite. “The height causes a high path loss and a large RTT. The mobility of an LEO satellite introduces a very high Doppler offset on the radio link, and it also inevitably requires all devices to frequently change their serving nodes. Rel-17 establishes basic mechanisms to manage these challenges and provides a first set of specifications to support NTNs based on NR, NB-IoT and LTE-M.”
Satellite part of the 3GPP vision for ubiquitous communications
In a previous webinar, German company Rohde & Schwarz said that 3GPPs vision of ubiquitous communication included the usage of satellite or airborne based network components since the beginnings. However, the firm noted that early trials and implementations never took off successfully due to commercial reasons.
“In the short history we saw a tremendous development in the satellite and aerospace community as well as in worldwide wireless communication requirements. With the new work item under development in 3GPP, the vision of ubiquitous communication networks including satellite and airborne can become a reality,” Rohde & Schwarz said.
“Satellites from LEO to GEO or airborne base stations (HAPS) can be launched and connected to terrestrial ground stations in a feasible way. Radio technologies like beamforming and 5G numerologies support a reliable connection from mobile devices to stations in high altitude,” the company added.
