Abstract
Improved coverage, high data rates and Quality of Service (QoS) constitute essential features of 5G networks. The adoption of massive MIMO and millimeter-Wave (mmWave) technologies did not only improve these features but also resolved the spectrum limitations faced in 4G. Among the many resulting emerging vertical industries, Connected Autonomous Vehicles (CAVs) along with vehicle-to-everything (V2X) communications are deemed to transform the transportation landscape with numerous far-reaching societal and economic benefits. However, high mobility scenarios pose additional challenges in vehicular communications due to the rapid change in the environment, and specifically the channel coefficients. Thus, with the growing demand for such communication systems, wireless concepts for data exchange in time-variant networks become increasingly interesting.In this work, the enabling technologies, major challenges and significant opportunities mmWave frequencies can introduce to vehicle-to-infrastructure (V2I) communications are discussed. Using a ray-tracing approach, the effects of the propagation channel on high mobility mmWave applications are studied. A spatiotemporal characterisation of the environment is performed, and the antenna design parameters’ effects are explored. Physical radiowave propagation models for mmWave are also used to assess as well as improve the achievable throughput, coverage and Signal-to-Noise-Ratio (SNR) in High-Speed Train (HST) and urban environments using reduced resolution, non-uniform codebook schemes.
The proposed designs operate on the premise that line-of-sight (LOS) rays dominate the mmWave links, and the sectors with the highest antenna gain are the ones around the LOS ray direction, aiming to find the sectors which cover the LOS ray in fewer search steps. Codebook solutions are shown to provide the best performance compromise between data rates, outage percentage and AP separation, allowing constant connectivity between terminals though with an increased variability of throughput. Beamforming setup time is also shown to be reduced significantly while at the same time keeping throughput stable. Finally dynamic sector design in conjunction with multi-stage BF processeses is applied in urban vehicular architectures and is shown to significantly reduce time to setup and subsequently the effects of channel aging in mmWave environments.
| Date of Award | 21 Jun 2022 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Angela Doufexi (Supervisor) & Simon M D Armour (Supervisor) |