Analysis of mimo antenna configuration effects on Wimax Network deployment in Ghana

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Worldwide Interoperability for Microwave Access (WiMAX) technology has gained growing interest due to its applications and advantages. It is fast emerging as a last-mile problem solution for broadband access technology. This thesis presents operational scenarios for the deployment of a Fourth Generation (4G) WiMAX system in a typical Sub-Saharan African environment. The work in this research has been specified based on real world conditions considering the regulatory rules stipulated by the National Communication Authority for radio frequency spectrum utilization in the 2.6GHz licensed band in Ghana. Appropriate propagation models and network planning tools have been used to design the optimized final radio network plan for the various Multi-Input Multi- Output (MIMO) configurations. A parameter called Interference to Noise Ratio (INR) was introduced to optimize the BER performance of the deployed 2x2 MIMO configuration in the presence of multiple interferers. The INR parameter was used to fit the BER results and then subsequently optimize the 2x2 MIMO configuration performance in the striped case to create a wide virtual bandwidth. The fitting INR parameter helped to improve the BER performance once the threshold INR was exceeded. This result extends the principle of successive decoding to MIMO systems affected by partial band interference under the assumption of a common receive correlation matrix. Unsuppressed sidelobe emissions also distort the performance of MIMO antenna systems used in deploying multicarrier networks. In order to accurately evaluate the performance of the MIMO antenna configurations used in the network deployment scenario, a mathematical model for estimating the effective beamwidth and sidelobe suppression factors for MIMO antenna systems used in multicarrier deployment scenarios was developed. The derived step function can be used to minimize the effect of antenna sidelobe emission in a realistic iii deployment scenario and also as an operational guideline tool to model added isolation factors. This function may provide a means to determine practical antenna sidelobe suppression factors in subsequent WiMAX deployments. Coverage, capacity, and interference predictions have been performed using MATLAB, 4-NEC 2 and Genex-U-Net for the predefined areas of Accra and Tema, Ghana. Simulation results for different downlink/uplink ratios with different frequency reuse schemes and antenna configurations have been presented. A total of 11 base stations have been suggested to provide coverage of -92dBm using 32 sectors adaptive 4x4 MIMO antenna configuration to provide a 3dB gain over the deployed adaptive 2x2 MIMO system thereby reducing deployment cost. Finally, based on the high system performance of the evaluated network, secure communication models and network architectures have been proposed in three case study areas. Keywords: Performance Evaluation; Capacity Simulation; Interference Modeling; WiMAX Radio Planning; Successive Cancellation Technique.
A thesis submitted to the Department of Electrical Engineering, Kwame Nkrumah University Of Science And Technology in partial fufillment of the requirement for the degree of Doctor Of Philosophy in Telecommunications Engineering.