A Novel Transmitter Placement Scheme For Indoor Wireless Coverage Optimization

With the increasing demand for wireless applications and services in indoor environments in urban areas, such as telephony, video communication and data transmission on mobile terminals, the design and implementation of indoor coverage systems have become areas of research focus. Such systems have a number of advantages over their conventional wired counterparts in that they provide users with convenient and flexible services while lowering the costs of installation and maintenance.One important issue in planning indoor wireless coverage systems is how to place the transmitters in a cost-effective way, that is, to ensure desired coverage in the building by using a minimum number of transmitters, as the system construction cost depends largely on the number of transmitters. In addition, an optimized transmitter layout could reduce leakage power and at the same time meet the performance requirements with fewer transmitters. Traditionally, transmitter placement design is performed manually, which requires large amounts of site measurement. This process is very time-consuming, yet could rarely find the optimal transmitter placement. Many computer-aided techniques have also been developed to help engineers determine the number and locations of transmitters in indoor wireless communication system. While these approaches facilitate the transmitter placement design a lot, most of them can not automatically determine the both the number and locations of the transmitters in an indoor coverage system. Moreover, these methods could not handle relatively large environments either. According to their experimental results, none of these approaches are tested in sites that need more than ten transmitters to cover, while such sites are quite common in real-world indoor wireless communication systems.In this thesis we take a variety of factors that influence the design of indoor coverage systems into account to propose an automatic transmitter placement scheme. The paper consists of four parts: the basic components of the indoor wireless coverage systems; the indoor wireless propagation prediction models and parameter adjustment; the optimization techniques for transmitter location optimization and a systematic solution for transmitter placement design in indoor environments. Our paper starts with introducing the types and structure of typical indoor coverage systems. Then it presents several commonly used indoor propagation prediction models and a parameter adjustment approach based on least square method. The parameter adjustment results in three sites are also presented. Finally we give an iterative method for automatically determining the minimum number and optimized locations of the needed transmitters in an indoor coverage system. By incorporating a novel adaptive transmitter number adjustment algorithm with a two-step transmitter location optimization algorithm, our method can converge to the minimum number of needed transmitters very quickly and this makes it applicable even to sites that require tens of transmitters to cover. The effectiveness of our proposed method is demonstrated by comparison to the exhaustive enumeration test, manual placement designs produced by professional RF engineers and the genetic algorithm.