With the surge in smartphones and tablets, the future of wireless cellular communication systems is marked by a drastic change in user behaviour triggered by the unbridled growth of bandwidth hungry applications. This challenge as well as the limited spectral resources drives the need to further improve resource allocation schemes for cellular networks. This thesis focuses on resource allocation in self organised cellular networks. A distributed self organised channel assignment scheme has been proposed that is shown to achieve perfect orthogonality among neighbouring sectors and reveals the importance of localised rules in designing distributed self organised systems. We define a sectorial neighbourhood based on intercell interference consideration and apply a local coordination among these sectors to achieve a self organised assignment. This unique solution for spectrum assignment strategy is demonstrated as a dynamic spectrum allocation scheme as well as a combination of both the dynamic and static spectrum allocation schemes, verified by system level simulations. The marked improvement in system performance is however not evident for users located at cell edges. Due to the performance of these cell edge users, a self organised fractional frequency reuse scheme whose allocation adapts to the system dynamics is proposed. Current solutions that employ a Fractional Frequency Reuse (FFR) are first analysed to challenge the assumption of fixed cell edge region and power allocation irrespective of the unique user distribution in each cell and its neighbours. We define a unique property for each sector based on its user distribution called its Centre of Gravity (CoG). With the CoG, each sector is classified into states that enables us to apply cellular automata theory that results in a self organised fractional frequency reuse scheme. For mulithop communication links however, intercell interference analysis becomes more complicated due to interference introduced by relay nodes. We finally investigate FFR schemes in multihop communication links comparing the performance of existing FFR schemes in multihop links in terms of their spectral efficiency and area spectral efficiency. A new FFR scheme specifically tailored for multihop links is thus proposed by applying a reuse scheme both in the cell centre and edge regions but rotated at an angle of 1200 in the centre region. Furthermore, the sectorial neighbourhood principle introduced earlier is further applied to ensure intercell interference is further minimised.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:580334 |
| Date | January 2012 |
| Creators | Aliu, Osianoh Glenn |
| Publisher | University of Surrey |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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