Broadband connectivity with high-altitude platforms

*This article was originally published in the recent ITU News Magazine edition “Managing spectrum for evolving technologies.” Any views expressed in this article do not necessarily reflect those of ITU.

Recent estimates from the ITU Telecommunication Development Sector (ITU–D) indicate that in 2018, more than 48% of individuals all around the world were still not using the Internet (see the Measuring the Information Society Report 2018). Focusing the analysis on the least-developed countries, it was found that four out of five individuals globally are still offline. Providing Internet access to those individuals is an enormous challenge that has not yet been tackled.

Although terrestrial and satellite technologies have been successfully playing their roles in providing connectivity, the numbers clearly show that there is a lot of room for improvement of those indicators. Connecting the unconnected is a very important step for the development of an information society with more inclusion and reliability.

WRC‑19’s role in helping to connect the unconnected

The World Radiocommunication Conference 2019 (WRC‑19) will have the opportunity to contribute to reducing this gap by promoting a more efficient usage of spectrum. Access to spectrum is fundamental to foster the development of a myriad of business models that will enable the connection of the unconnected.

In this regard, new spectrum identifications for high-altitude platform systems (HAPS) will be discussed at WRC‑19, and the existing ones will be reviewed.

ITU studies on HAPS

During this study cycle, the ITU Radiocommunication Sector (ITU–R) has conducted studies to assess the spectrum needs for HAPS to address Resolution 160 (WRC‑15) — WRC‑19 agenda item 1.14 (to consider, on the basis of ITU–R studies in accordance with Resolution 160 (WRC‑15), appropriate regulatory actions for high-altitude platform stations (HAPS), within existing fixed-service allocations).

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The studies considered several aspects such as the evolution of the concept, the state-of-the-art of the technology, and the requirements of new broadband applications.

The studies (see Report ITU–R F.2438‑0 (11/2018)) indicate that there is a need for almost 3 GHz of additional spectrum for HAPS to meet
the requirements of certain applications (see system 6 in Report ITU–R F.2438‑0 (11/2018)).

This is much more than the 600 MHz that are currently identified worldwide for HAPS operating in the fixed service (additionally, to the fixed service identifications, some bands were identified for HAPS operating in the mobile service as IMT base stations. See Radio Regulations (RR) Footnote 5.388A).

ITU–R began to study spectrum identifications for HAPS in the 1990s. The telecommunications ecosystem and technology enablers for HAPS
have evolved a lot since then.

Large-scale deployment of HAPS will be enabled by such a remarkable evolution of the technology, but it still struggles with the lack of spectrum bands identified for this purpose.

Solar-powered, light-weight platforms are examples of the current state-of-the-art of a technology that can be used to provide affordable

broadband connectivity in unserved areas.

Large-scale deployment of HAPS will be enabled by such a remarkable evolution of the technology, but it still struggles with the lack of spectrum bands identified for this purpose.

The WRC‑19 agenda dealing with HAPS

The WRC‑19 agenda item 1.14 will discuss the possible use of several frequency bands for HAPS broadband systems, some of them for worldwide usage, some for regional usage, some already identified for HAPS (Resolves to invite ITU–R 2 and 3 in Resolution 160 (WRC‑15)), some already allocated to the fixed service (Resolves to invite ITU–R 4 in Resolution 160 (WRC‑15)).

In these discussions, it will be very important to consider that the harmonized use of spectrum will bring to the ecosystem many benefits and it will facilitate achieving economies of scale.

This is especially desired for a system like HAPS, which aims to connect individuals who are offline and live mostly in the least-developed countries.

Economies of scale will be crucial for successful low-cost deployments of HAPS technology.

Additional means of connecting the unserved

It is noteworthy to mention that a global largescale deployment of HAPS is not foreseen to occur at the expense of other connectivity solutions.

On the contrary — it presents itself as an innovative proposal — an additional way to connect unserved and underserved areas.

The operational characteristics of the platform, which is defined in No. 1.66A of the Radio Regulations as “a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the Earth”, enables the possibility of moving it to areas with higher-connectivity demands, and makes it a suitable communication solution to support, for example, natural disaster relief missions in areas that become disconnected all of a sudden. Solar-powered platforms also have a fast and environmentally-friendly deployment.

Feasibility of the candidate bands for HAPS

Several technical studies have been conducted by ITU–R to evaluate the feasibility of the candidate bands for HAPS. Such studies can be found in recently published reports, such as F.2471, F.2472 and F.2475).

Now it is up to the WRC‑19 to decide whether these bands will be identified and what possible changes would be required to the Radio Regulations. The regulatory provisions should not impose undue constraints or unnecessary limitations for countries wishing to deploy this technology to give a chance for this application to succeed.

Instead, they should establish reasonable conditions for implementation of the systems, facilitate access to spectrum considering the most recent advances of the technology, ensure protection of incumbent services, and enable the shared use of the bands for more efficient usage of the spectrum.