Mobile communications channels involving people and vehicles

As wireless connectivity becomes increasingly popular, a greater emphasis will be placed upon the seamless integration of dissimilar networking technologies. One such example of this will occur in urban environments, where diverse types of networks are expected to operate in close proximity to one another. The work in this thesis has focused on understanding how these emerging communications channels may coexist. In particular, by studying how wearable communications channels may be influenced by nearby vehicles, or even forming part of a much larger vehicle-to-everything network. Due to the complex nature of the propagation mechanisms that support communications within these networks, previous measurements and analysis performed for each channel in isolation are unlikely to accurately depict the compounded effects that influence the received signal power. Firstly, the impact vehicular traffic may have on wearable-to-wearable devices when operating in the same vicinity was investigated through detailed measurements. Most notable, was the introduction of a categorisation system for vehicles based on their size and shape, which enabled a systematic analysis of channel disturbances and the vehicle-induced fading conditions. Secondly, a natural extension of this work, considered the interconnectivity of wearable networks with passing vehicles. These vehicle-to-pedestrian communications channels are an important part of future vehicular networks, particularly in relation to road safety. The research focused on the individual fading mechanisms responsible for shaping the vehicle-to-pedestrian channel, highlighting similarities between existing vehicle-to-vehicle channels as well as key differences that make the work presented here vital in improving our understanding of the vehicle-to-pedestrian communications channel. Lastly, an airborne vehicle was considered to form part of a person-to-vehicle channel, namely the use of an unmanned aerial vehicle (acting as a base station or relay) to form part of future cellular networks. In all studies, the significance of body orientation for the wearable devices was also investigated, in the process helping to determine the role of the human body shadowing in shaping the characteristics of the received signal. This included scenarios where the person remained stationary and walked, enabling a study of the impact mobility has on the fading characteristics of these wireless channels. The results presented in this thesis, provide invaluable insight into the challenges faced by wireless system designers that must be overcome to create robust networking solutions that can mitigate signal interference and dropouts. The fading models and their parameter estimates can be used to design forward error correction methods and antenna systems to improve signal reliability and network signal coverage. Using simulation techniques and the information provided in this thesis, these V2X channels can be readily reproduced for incorporation into ITS network simulations.