The mobility that wireless communication offers to users, added to the ease of installation have increased the demand on such communication systems. However, the main drawback of wireless communication is the degradation of the signal as it travels through the channel due to the different propagation mechanisms the signal undergoes. To minimise the effect of the channel and get the best service, the base stations must be appropriately located within the environment. This requires proper knowledge of the channel characteristics. Ray tracing software is used throughout this work to generate the channel characteristics of an indoor environment. After getting the channel characteristics, a novel cost function is defined based on the path loss values and it is then optimised. Once the optimal base stations’ positions are found, the minimal amount of power required to cover a predefined percentage of the possible receivers’ locations is calculated. On the other hand, a receiver’s position acquiring enough field strength does not necessarily enjoy the service. This depends on the time dispersion parameters values relative to the symbol rate. The time dispersion parameters have always been ignored in the literature while finding the optimal base stations’ locations. Three cost functions that take into consideration both the path loss and rms delay spread, for the first time in the literature, are therefore defined. The cost functions are optimised and their corresponding results are compared. Furthermore, indoor environments have always been considered static which is never realistic. They are subject to continuous changes such as opening doors and windows as well as the presence of people. The first detailed analysis and quantified results of the effect of a dynamic environment on the optimal base stations’ positions and minimal emitted power are presented. It is shown that the optimal base stations’ locations and minimal emitted power are sensitive to such environment changes. The environment changes can also disturb the service for active receivers. Three techniques to overcome the effect of environment changes and bring the disturbed service back to receivers are proposed. The first two techniques rely on increasing the emitted power or changing the antenna polarisation. The third technique is a novel technique that gives the base station the ability to automatically move in various directions within a limited distance. The techniques are tested and their efficiency and limitations are discussed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:681053 |
| Date | January 2015 |
| Creators | Minkara, Rania |
| Contributors | Shepherd, Peter |
| Publisher | University of Bath |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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