Grant: Discovery Grants Program - Individual

In this research program, a novel wireless network architecture for 2030s (6G) and beyond (B6G) will be presented with a new access layer composed of HAPS (high altitude platform station) constellations between the satellite and terrestrial networks. A HAPS can be thought as a base station at stratosphere (at an altitude of around 20 km) at a specified, nominal, fixed point relative to the Earth. It is becoming exceedingly difficult for the legacy terrestrial wireless network, no matter how much it evolves, to cope with the continuously increasing and steadily becoming more ambitious connectivity expectations of humans, machines, and robots, mainly due to the fact that with the fixed locations of base station (BSs), the network is never agile enough to handle the highly dynamic (and increasingly unpredictable) user demand in space and time. The current brute-force solution of densifying the network blindly with more and more BSs is not sustainable, as it results in very high deployment cost (which impacts the connectivity fees) and consumes an excessive amount of energy with a high carbon footprint. There is a rapidly growing interest in non-terrestrial networks (NTN) within the framework of a futuristic integrated terrestrial-aerial-satellite network architecture. In this proposal, we will focus on a particular type of aerial access node within the envisioned architecture, HAPS, in particular for densely populated metro (urban and suburban) areas. The aim is to construct a tightly-integrated 3-dimensional heterogeneous network with terrestrial small and macro base BSs compounded with a third tier of HAPS-based super macro BSs. The earlier HAPS discussions have been occurring almost exclusively in the context of remote and rural coverage which can arguably be served more efficiently by satellite networks. The novel HAPS vision which will be studied in this research program, on the other hand, is mainly for urban areas towards the sustainable and smart cities and societies of the future. With its bird's-eye view of an entire metropolitan area, a HAPS has the potential of presenting unprecedented opportunities for integrated communications, computing, sensing, positioning, and so on, in line with the emerging 6G paradigm of integrated everything. Advanced antenna technologies in the form of steerable beamforming and ultra massive MIMO will be among the key enabling HAPS technologies. Utilization of artificial intelligence (AI) for the control & management of the integrated HAPS-terrestrial network will also be crucial. With their connectivity, edge computing, caching, sensing, and localization capabilities, the forward-looking HAPS networks have the potential of being disruptive and transformative in 2030s and 2040s.