| Summary: | This dissertation investigates wireless resource allocation problems that arise when supporting Urban Air Mobility (UAM) with ground-based cellular infrastructure. One of the major challenges in integrating aerial users into terrestrial networks is interference management since aerial users would interfere with terrestrial communications at multiple terrestrial base stations (BSs) due to their largely favorable channel conditions.
In this dissertation, several scenarios of practical interest in the context of integrating aerial users into ground-based cellular networks are investigated. The focus is on using multiple access schemes to manage interference between aerial and terrestrial users, and several of such schemes are studied. In particular, the performance of rate-splitting multiple access (RSMA) and non-orthogonal multiple access (NOMA) schemes are investigated and compared with traditional orthogonal multiple access (OMA). Several communication scenarios with a single aerial user and one or more BSs with one associated terrestrial user each are carefully considered, with suitable channel models defined by the third-generation partnership project (3GPP).
Furthermore, resource allocation problems for orthogonal frequency division multiple access (OFDMA) based systems with different multiple access schemes to multiplex both an aerial and a terrestrial user on each subcarrier are formulated and solved. As the formulated problems are non-convex, suitable transformations and approximate solution methods are identified to find optimal/close to optimal solutions.
Simulation results demonstrate that in terms of achieving minimum sum power in the system, NOMA performs the best, while RSMA can also achieve the same performance as NOMA. Nevertheless, the dissertation highlights the potential of RSMA in improving the performance of UAM communication systems and suggests further research to address the challenges in practical applications.
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