Optimisation of Base Station Placement for Indoor Wireless Communications

Abstract

The development of wireless communication systems has enabled 'anywhere, anytime' communication and significantly influenced the working habits of the people in modern society. Engineers responsible for deploying base stations in wireless systems face opposing constraints of maximising the quality and capacity of the system while minimising the interference and cost. In addition, indoor wireless systems must cope with three-dimensional variations in signal strength and limitations in site selection. Consequently, the indoor Base Station Placement (BSP) problem becomes a multi-objective, multi-dimensional optimisation problem. This thesis investigates the BSP problem for indoor wireless communication systems by using mathematical models and optimisation algorithms and considering the effect of several factors on BSP. Researchers have proposed a number of algorithms to find the optimal solution for the BSP problem. In this thesis, some proposed algorithms are compared to identify the most appropriate algorithm to solve the indoor BSP problem. Based on the advantages and disadvantages of the existing algorithms, a novel hybrid algorithm is developed and its performance is compared to the existing algorithms. It is seen that the proposed hybrid algorithm provides optimal deployments, without significantly compromising accuracy and efficiency. Although there are several factors that can affect BSP in indoor wireless systems, the effects of three factors, namely call traffic variability, user mobility and call switching technologies on BSP are investigated. Two options are considered for each factor - call traffic can be static or dynamic, users can be fixed or moving and call switching technology can be circuit or packet switched. It is seen that dynamic call traffic, user mobility and circuit switched traffic must be considered in order to identify the optimal BSP. In addition, the BSP problem is extended to multi-floored buildings by considering internal and external potential base station sites. It is seen that the vertically aligned internal base station sites achieve the least call failure rate. The results obtained from this thesis are intended to provide a practical and useful framework for solving the BSP problem of indoor wireless communication systems.