Models Of Co-channel Interference And Handover For Cellular Mobile Communications

How to improve the capacity of mobile cellular communication systems have been attracting great interests of industry and researchers. This dissertation deals with two major issues of improving the capacity of the system, namely, co-channel interference and handover. Recent research indicates that the geometry of the system fundamental unit, i.e., cellular, has immediate influence upon the two major issues. Therefore, this dissertation will focus on the following three key aspects related to the two issues, i.e. (1) research an improved analysis model of co-channel interference based on cellular geometry; (2) research an improved analysis model of handover based on cellular geometry; (3) research on the co-channel inference and handover of a proposed hierarchical cellular configuration based on adaptive multi-beam base-station antennas.The main research work and contributions of the dissertation include the following aspects:1. Since the existing analysis model for co-channel interference generally considers that the inference power from the interfering cells will interfere all the active users on the downlink, this dissertation proposes an improved analysis model for co-channel interference considering the users' position probability distribution in the desired and interfering cells, where the inference power from the interfering cells will interfere only partial active users on the downlink. Simulation results show that the improved analysis model can enhance precision in calculation of co-channel inference.2. Different from the existing analysis model for co-channel interference, which normally expresses the users' position probability distribution referring its home base-station as the coordinates origin. This dissertation proposes an improved expressing model, which refers its home base-station (desired signal) or interfering base-stations (interference signals) as the coordinates origin on the up and down link. Theoretical results show that the proposed model will touch the relations between the co-channel calculation and the users' position probability distribution.3. Since the existing analysis model for co-channel interference normally get the average co-channel interference by continuous integral over the cells due to the continuous users' position probability distribution. This dissertation further proposes an improved analysis model for co-channel interference by introducing the order statistics, which will produce a discrete users' position probability distribution press close to the real occurrence. Theoretical results show that the proposed model can directly introduce the active users or channels in the cells into the co-channel calculation.4. Different from the conventional cell dwell time analysis model considering the users moving direction and velocity in a specified disc region. This dissertation proposes analyzing the probability density distribution of dwell time should consider the users' position probability distribution and moving direction and velocity in a specified sector region. Theoretical and simulation results show that cellular geometry and the users' position probability distribution influence the probability density distribution of dwell time and the performance of cell traffic.5. This dissertation proposes and researches the relations between the beam width of the smart antenna and the probability density distribution of dwell time. Simulation results show that smart cellular will increase the dwell time and improve the performance of cell traffic.6. This dissertation proposes a novel hierarchical cellular system. Different from conventional hierarchical cellular system, the proposed one is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The validity of the proposed has been checked through spectrum efficiency and dynamic coverage with simulation results.