As mobile networks evolve toward sixth generation (6G) communications, the industry is confronting a difficult reality: no single network layer can meet every requirement for coverage, latency, resilience, scalability, and cost.
Terrestrial networks deliver strong performance in dense urban areas, but expansion into rural and remote regions is expensive and operationally difficult. Low Earth orbit (LEO) satellites provide broad coverage, but they also face challenges, including congestion, latency, spectrum crowding, and short operational lifespans.
The latest white paper from the HAPS Alliance examines a third layer that is increasingly moving into focus: high-altitude platform stations (HAPS).
Often described as “cell towers in the sky,” HAPS operate in the stratosphere at roughly 20 kilometers above Earth. Positioned between terrestrial infrastructure and satellites, HAPS can provide regional coverage with lower latency than satellites, flexible deployment, and direct-to-device connectivity using standard handsets.
But the white paper is not simply an argument for HAPS as a replacement technology. Instead, it introduces a practical framework for how terrestrial base stations (TBS), HAPS, and LEO satellites can coexist and work together.
The paper calls this the “3Cs” framework:
- Cooperation
- Complementarity
- Competition
That framework provides a structured way to think about how different network layers should interact depending on geography, application requirements, economics, and operational constraints.
This matters because future communications networks will not operate as isolated systems. They will increasingly function as coordinated multi-layer architectures combining terrestrial networks and non-terrestrial networks (NTN). That convergence has major implications for telecom operators, aerospace companies, network architects, regulators, equipment vendors, and standards organizations.
One of the paper’s strongest points is that the “best” network layer depends heavily on the use case. The paper goes beyond theory and maps the 3Cs framework onto real operational use cases, including:
- Emergency communications
- Smart cities
- Flash crowd connectivity
- Deep rural broadband
- Tactical and strategic communications
- Precision agriculture
- Environmental monitoring
- Electric vertical take-off and landing (eVTOL) operations
- Unmanned aircraft systems (UAS)
The white paper also explores scenarios where the technologies work together rather than compete directly.
For technical readers, one of the more valuable sections examines the enabling technologies required to support these architectures. The paper discusses phased-array antennas, integrated access and backhaul (IAB), software-defined networking (SDN), network function virtualization (NFV), hybrid free space optics (FSO) and radio frequency (RF) backhaul, regenerative payloads, and dynamic spectrum coordination.
Importantly, the white paper also addresses the hard problems.
What you’ll learn in the white paper:
- Why HAPS, LEO satellites, and terrestrial networks each solve different connectivity problems.
- How the 3Cs framework defines cooperation, complementarity, and competition between network layers.
- Which deployment scenarios favor HAPS, LEO, or terrestrial systems.
- How hybrid architectures can improve resilience, coverage, and quality of service (QoS).
- What enabling technologies are needed for multi-layer NTN integration.
- Where current standards and regulatory efforts are headed.
- Which technical and operational challenges still need to be solved.
The future of connectivity will not be built around a single platform. It will depend on how terrestrial, aerial, and satellite systems operate together.