The Research And Simulation Of Coexisting Interference And Propogation Models In Mobile Commnunication Network Planning

The rapid development of information technology has given birth to the emergence of wireless networks, which have been playing a very important role in people’s daily lives. However, by using different network protocols, this wide variety of wireless networks are different from each other in network topology, network coverage, air interface structure and so on. Given people’s demand for next-generation mobile communication networks, the convergence of mobile communication networks has become the trend of network development, by which the heterogeneous wireless networks could be integrated.In the context of the mobile communication network convergence, network planning is facing more challenges. In the overlapping area of wireless access networks, each network will inevitably interfere with each other, which will has very negative impact on service quality of the mobile communication networks. What’s more, by introducing vertical handoff technology, the user distribution in the each access networks will be adjusted with network conditions, which in turn makes the coexisting interference becomes much harder to be predicted. This thesis focuses on the coexisting interference of mobile communication networks which adopt the vertical handoff mechanism.According to the characteristics of different heterogeneous access networks, this thesis presents a noble vertical handoff algorithm which takes both user’s QoS requirements and network conditions into account. By making a tradeoff between service preference and the system performance, the algorithm aims to select the optimal target network for the mobile terminal under the current network conditions. Then the thesis proposes the coexisting interference model after introducing the vertical handoff mechanism and evaluation metrics to evaluate the impact of the coexisting interference. By selecting the TD-SCDMA, TD-LTE and WLAN networks to build a system-level simulation platform, the thesis gets extensive simulation results which confirm that the proposed vertical handoff algorithm provides higher access satisfaction rate, improves the mobile terminal’s receiving performance and the overall system throughput at the same time.Propagation model is one of the most important foundations of the mobile communication network planning and the coexisting interference analysis. This thesis also conducts the research on the propagation model calibration algorithm based on least squares method which is widely used in the mobile communication network planning simulation software. Furthermore, this thesis also proposes an improved calibration algorithm based on the weighted least squares method and uses the measured path loss data to give the performance simulation contrast of the two calibration algorithms. The contrast results confirm that the improved calibration method can speed up the calibration process with minor loss of calibration precision, which improves the operating efficiency of network planning simulation software.