5G from space: The final frontier for global connectivity

The lack of ubiquitous network coverage from terrestrial cellular networks can be disruptive not only to industry and enterprise, but even the safety of individuals when they most need connectivity. 5G coverage from space has the potential to make connectivity to the Internet truly ubiquitous for a broad range of use cases.

Qualcomm’s long history of innovation in satellite communications

After the commercial success of the OmniTRACS two-way satellite mobile communications system launched in 1988 for trucking and logistical companies, Qualcomm and Loral Corporation launched the Globalstar project as a joint venture in 1991. The Globalstar system used CDMA technology and 48 low earth orbit (LEO) satellites to provide continuous coverage anywhere in the world to a comprehensive array of devices.

Today, while multi-mode satellite phones provide users access to terrestrial and satellite connectivity, they are typically non-mainstream devices using different technologies for terrestrial and proprietary satellite connectivity.

At Qualcomm, we realized the potential to transform the smartphone experience by unifying terrestrial and satellite connectivity with one technology standard for mass adoption. This conviction made us drive a satellite connectivity pivot in the 5G standardization effort at the 3GPP. Qualcomm Technologies has led the R&D for satellite communications capabilities in the 5G Release 17 standard, and continues to drive satellite connectivity in 5G Advanced for both end user devices and IoT.

3GPP Release 17: The dawn of 5G Non-Terrestrial Networking

As part of the Release 17 standardization effort, 3GPP pursued a range of solutions for 5G non-terrestrial networking (NTN) based on options for the type of non-terrestrial platform, and the use cases supported. The platforms supported are satellites at various orbits (GEO/GSO, MEO, and LEO), high-altitude platform station (HAPS), and unmanned aerial vehicles (UAV). Some of these platforms are intended to remain stationary relative to the earth, with non-steerable coverage, while other platforms could either move in relation to the earth or have steerable coverage. The Release 17 standard therefore includes support for both earth-fixed and earth-moving coverage beams.

Release 17 solved the key challenges to 5G connectivity with non-terrestrial platforms – long propagation delays, moving cells, and the large Doppler shifts associated with the platforms moving at high speed. Release 17 includes these solutions in two 5G technologies to serve different use cases – IoT-NTN and NR-NTN, both of which are candidate technologies for IMT-2020-Satellite classification.

5G NR-NTN is designed to complement terrestrial networks with non-terrestrial coverage in under-served areas, e.g., remote rural areas, coverage gaps, etc. While delivering less capacity and data rates than a densely deployed terrestrial network, 5G NTN makes possible a ubiquitous 5G user experience with support for mobility between terrestrial and non-terrestrial coverage. Rel-17 5G NR-NTN leverages satellites in transparent bent-pipe mode, and the 5G Standalone (5G SA) architecture, with a 5G gNB and 5GC core network, to serve throughputs ranging from 1 to 10 Mbps, or higher with more spectrum. Use cases for 5G NR-NTN include messaging, voice over NR (VoNR), and mobile broadband service to smartphones and embedded devices, fixed wireless access, automotive and mobile compute connectivity, and satellite backhaul for cell towers in remote locations.

5G IoT-NTN is designed to expand the addressable market for massive IoT with non-terrestrial coverage. It provides throughputs ranging from 1 to 100 kbps to Rel-17 NB-IoT and eMTC devices via satellites in transparent bent-pipe mode. For lower bandwidth services like NB-IoT, the bent-pipe architecture supports rapid deployment of new services over existing satellites since only the endpoints – the ground station and the user device – need to be upgraded to support the new service. The NB-IoT or eMTC carriers are generated by a base station connected to the ground station at one end and an EPC core network at the other end. Use cases for 5G IoT-NTN include personal safety and messaging, environmental sensors, point of sale devices, utility meters, and tracking logistics. IoT-NTN can provide universal coverage for IoT devices even in areas where terrestrial networks may not be deployed, e.g. in remote rural areas, for shipping containers at sea, etc.

3GPP designated two frequency bands in Release 17 for 5G NTN use, conditional on regional regulatory approvals. Both bands are in the 5G FR1 frequency range – n255 in the L-band (1626.5-1660.5 MHz UL / 1525-1559 MHz DL) with 34+34 MHz FDD bandwidth, and n256 in the S-band (1980-2010 MHz UL / 2170-2200 MHz DL) with 30+30 MHz FDD bandwidth.

Mobile IoT-NTN and NR-NTN devices must support GNSS positioning to be able to pre-compensate for timing due to propagation delays and pre-compensate for frequency shifts due to motion-related Doppler effects when attempting to communicate via satellite. Devices dedicated to stationary use cases may operate without GNSS capability provided the device’s location is accurately configured.

A growing 3GPP ecosystem rallies in support of 5G NTN

Interest in 5G’s broad range of capabilities and the benefits of its global scale has seen many of the satellite industry’s leading companies join the 3GPP. Organizations like Airbus, CNES, ESA, Eutelsat, Hispasat, Hughes, Inmarsat, Intelsat, KT Sat, Leonardo, Lockheed Martin, and Thales are working closely with the cellular ecosystem in 3GPP to evolve satellite communications (satcom) with 5G.

Qualcomm Technologies collaborated with Ericsson and Thales for 5G NTN research, testing, and validation. A groundbreaking outcome from this collaboration was the creation of an on-the-ground end-to-end system realizing the 5G NR-NTN vision which included emulators for realistic NTN channels in terms of radio propagation and time delays. The connectivity chain included a mobile test platform (MTP) from Qualcomm Technologies to validate the smartphone form-factor for 5G NTN, a 5G radio satellite payload suitable for deployment on LEO satellites from Thales, and a 5G NTN virtualized radio access network (vRAN) prototype and 5G core network from Ericsson. The successful live demonstration of this system at MWC Barcelona 2023 was a major early milestone on the journey to commercializing 5G NR-NTN.

Qualcomm Technologies also recently launched new 5G IoT-NTN modems in collaboration with Skylo, a 5G NTN service provider, to enable ultra-low power and superior connectivity for IoT devices across satellite and cellular networks. Both chipsets support the Qualcomm Aware platform, which provides real-time asset tracking and device management in remote areas to support critical decision-making.

5G Advanced: Enhancing NTN applications and performance

Starting with the 3GPP Release 18 standard (due for completion mid-2024), 5G Advanced will fine-tune and enhance 5G NTN as part of the 5G evolution roadmap. Control channel and reference signal enhancements for improved coverage, support for discontinuous coverage, higher performance with very small aperture terminals (VSAT), and service continuity and mobility improvements for better transitions between non-terrestrial and terrestrial coverage areas are just some of the systemic improvements being worked on in Release 18.

Rel-18 5G NR-NTN will support new frequency bands for NTN above 10 GHz, e.g., in the Ka band, for much higher carrier bandwidths and network capacities. Bands n510 (27.5-28.35 GHz UL / 17.7-20.2 GHz DL) and n511 (28.35-30.0 GHz UL / 17.7-20.2 GHz DL) are to be proposed for consideration by the FCC for the US. Band n512 (27.5-30.0 GHz UL / 17.7-20.2 GHz DL) is to be proposed for consideration by the CEPT for the EU. An aspect worth noting is that these new bands do not target smartphones but devices equipped with a larger antenna or antenna arrays, e.g. VSAT.

From a positioning perspective, work is also underway at the 3GPP to reduce the dependency on GNSS for NTN use cases, and to introduce network verification of device location with multiple round-trip time (multi-RTT) measurements.

Evolving satellite communications for sustainable commercial success

Attempts in the past to bring satellite communications to the masses did not have the advantage that 5G brings – that of a single technology standard which can help mobile network operators and satellite connectivity service providers around the world complement each other’s networks for ubiquitous connectivity with cost-efficient and popular devices. The broad range of use cases 5G NTN has been designed to serve, the momentum of the 3GPP ecosystem, and the 3GPP technology evolution roadmap can only benefit the 5G NTN value proposition for sustainable commercial success.