Research And Implementation Of Capacity Emulation Based On TD-LTE Air Base Station

When natural disasters occur, the communication network in the disaster area can be easily paralyzed, resulting in disaster situation transmission and rescue operations can't be effectively carried out. When carry out the field rescue or scientific investigation in the communication blind area, with no long-distance means of communication will delay the rescue operation or scientific investigation. Based on the problem of setting up a communication network with wide coverage and stable coverage in the disaster area or communication blind area, this paper adopts the solution of using UAV to carry air base station. Based on the physical characteristics of the air base station, I researched the capacity simulation of air base station. The main work and innovation points include the following aspects:Firstly, a method based on the coverage area and the path loss in TD-LTE system is proposed to estimate the average throughput of the system. The different propagation models are analyzed, when the UAV flight at the low-altitude and the middle-altitude. Then I studied the effect of flight height on path loss and coverage of UAV. The simulation results show that the average throughput of the system increases with the increase of the flight height in the low-altitude space. The average throughput of the system decreases with the flight height in the middle-altitude space. And it can be concluded that there is a maximum value of the system average throughput between low-altitude and middle-altitude.Then, a method of forecasting coverage radius based on curve fitting between low-altitude and middle -altitude is proposed. The result shows that the flight height increases first and then decreases with the increase of the radius of coverage in the fitting curve. Based on the relationship between the flight height and the coverage radius of the air base station, a flight height determination algorithm based on the optimal coverage and the average throughput of the maximum system is proposed. The study shows that in the QPSK modulation mode, the peak of fitting curve is the maximum coverage radius. And when reaching the maximum average system throughput, the flight height is between the peaks of the 64QAM and 16QAM modulation mode' fitting curve. Based on the planning area and the maximum coverage radius, the algorithm of determining the number of air base stations and the hovering position is proposed. The algorithm can find the optimal location of coverage in a small area. Then I study in detail the modules of the capacity simulation including access control, resource scheduling and power control, which provide a theoretical basis for realizing the capacity simulation subsystem.Finally, this paper finishes the capacity simulation subsystem of TD-LTE air base station platform, and takes the scene of rescue and earthquake rescue application as examples to analyze the main users and corresponding services in these two scenarios in detail. Through the simulation platform, the simulation analysis of the coverage and capacity of the two applications are completed, which provides reference for the deployment planning of the air base station network system.