Next generation high performance systems are being standardised assuming a generic service delivery paradigm capable of supporting a diversity of circuit and importantly packet services. However, this flexibility comes at a cost which is the increased complexity of the dimensioning, planning, optimisation and QoS provisioning with respect to previous generation single-service mobile systems. Accurate system dimensioning is of fundamental importance and this thesis explores this requirement at two levels. Firstly, it departs from the common assumption of static users and examines what is the impact of mobile users on the system capacity. Secondly, it examines the impact of voice and web browsing services on the system dimensioning. In spite of the accuracy of dimensioning and planning, load imbalances occur for different reasons, which result in small-scale congestion events in the system. A load equalisation scheme is proposed which utilises the overlapping areas between neighbouring cells in order to eliminate the load imbalances. Essentially, coverage overlapping is needed in order to achieve ubiquitous coverage, hence to eliminate coverage holes. However, excessive overlapping results in capacity loss in interference-limited systems which is virtually the case with all modern systems. Radio coverage optimisation is needed but today this is performed on a cell-by- cell basis producing sub-optimal results. This thesis proposes an advanced coverage optimisation algorithm which takes into consideration simultaneously all cells within the considered area. For the operators (and also the proposed coverage optimisation algorithm) it is Imperative to have accurate path loss predictions. However, contemporary planning tools come with certain limitations, and often time-consuming and expensive measurement campaigns are organised. This thesis builds on the assumption that mobile systems will be able to locate the position of mobile terminals and subsequently proposes an automated process for the estimation of the radio coverage of the network. Lastly, the assumption regarding the positioning capabilities of the mobile systems Is further exploited in order to enhance the QoS guarantees to mobile users. Thus, various algorithms are examined which perform handovers towards base stations which maximise the survivability of the handed over calls.

Yes / Unmanned Aerial Vehicles (UAVs) are considered, nowadays, as a futuristic and robust paradigm for 5G wireless networks, in terms of providing Internet connectivity services onto infrastructure cellular networks. In this paper, the interference regime caused by multiple downlink aerial wireless transmission beams has been highlighted. This has been introduced by estimating the UAVs coverage area that is analytically derived in a tractable closed-form expression. The rationale of the analysed coverage approach relies on observing and adapting the joint aerial distance between the aerial base stations. This can minimize the intra-overlapped coverage and ultimately maximize the overall coverage performance for a better quality of service demands. The novelty of our approach brings useful design insights for UAVs system-level performance that technically helps in aerial coverage computations without the need of performing an aerial deployment setup. To the end, the performance effectiveness of our methodology has been tested under an urban propagation environment conditions, in which the original probabilistic channel model approximation has been taken into account. Moreover, this paper identifies the interference issue of such an aerial network as a shrinkage or distortion phenomenon.