Abstract:
The latest trends in computing devices, such as Personal Digital Assistants (PDA) and smart phones, contribute to the increasing demand for high rate wireless communication. Today, an appreciable number of wireless activities take place in indoor environments. This has led to the development of various wireless standards which offer wireless services in indoor environments, such as WLANs. Since indoor wireless networks such as these occur on unlicensed, shared frequency bands, interference becomes a limiting factor in the performance of indoor wireless systems. Multiple base stations deployed in indoor environments are also exposed to co-channel interference. Therefore, strategic planning in the deployment of base stations is important in order to maximize the capacity and quality of the wireless service, while minimizing the effects of interference. The research presented in this thesis involves modelling the error rate performance of OFDM receivers in the presence of multiple interferers. Analytical models to compute the BER have been developed recently. These analytical models, together with real measurements of received signals in various indoor environments, are used to model the error rate performance of the OFDM system. The effects of different base station deployment strategies on the error rate performance are investigated and performance comparisons among different indoor environments are presented. The result of the study shows that aligned configurations are favoured over the offset configurations in indoor environments with high SIR (dB) values. The investigation is carried out by first assuming that a single base station is deployed on each floor. The research is then extended by considering three base stations on each floor. It is found that the capacity of the wireless network increases by three times when the bandwidth is doubled. The error rate performance for an OFDM system in an indoor environment is then compared with the performance of a DS-CDMA system to investigate whether or not both systems favour the same base station configuration. Based on a particular system's requirements, the results and analysis presented in this thesis will be helpful to system planners in making decisions regarding the base station deployment strategy.