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.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:250770 |
| Date | January 2002 |
| Creators | Kourtis, Stamatis |
| Publisher | University of Surrey |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://epubs.surrey.ac.uk/843644/ |
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