Research On Base Station Layout Technology Based On TC-OFDM System

With the global networking of China’s "Beidou" system,users can achieve high-precision location positioning services outdoors.However,in complex environments such as urban canyons and indoors,satellite signals are easily interfered and blocked by these factors,resulting in users unable to receive satellite signals and unable to achieve positioning.In this scenario,the cellular network can achieve full signal coverage in indoor and outdoor spaces,but the positioning performance of the cellular network is very low.Therefore,the TC-OFDM system combines the advantages of the two to realize indoor and outdoor high-precision positioning services in wide-area scenarios.In this paper,the layout of base stations in TC-OFDM system is studied,and the base station layout methods in two positioning scenarios are mainly studied.The main contents and innovations are as follows:1.Aiming at the problem of base station layout of TC-OFDM system in the scenario of no signal occlusion,this paper proposes the weighted geometric precision factor(WGDOP)as the measurement standard of base station layout by analyzing the system measurement error in this positioning scenario.The smaller the WGDOP,the better the base station layout.the better.Compared with the traditional base station layout evaluation standard GDOP,the simulation results show that in the same positioning area,WGDOP is smaller than GDOP,and the difference between the two is 0.2.The mathematical model of the base station layout in the positioning area is proposed,and two different optimization algorithms are used to solve the optimal solution of the base station layout model.The simulation results show that the Monte Carlo algorithm is more suitable for solving the optimization model with constraints,and the base station layout is better.WGDOP value is relatively small.2.Aiming Aiming at the problem of the base station layout of the TC-OFDM system in the situation of signal occlusion,this paper analyzes the system measurement error in this positioning scenario,and needs to consider the delay error of the non-line-of-sight propagation of the signal,and calculates the weighting matrix in WGDOP.In this positioning scenario,it is necessary to consider both the maximum coverage area of the base station signal and the minimum average WGDOP of the positioning area.A multi-objective optimization model of the base station layout in the positioning area is proposed,and the MOEA/D algorithm is used to solve the optimal multi-objective optimization model.Then,the optimal position of the base station layout in the positioning area is obtained.The simulation results show that the positioning area 4 base station layout can make the coverage rate of the positioning signal reach 68%,and the positioning accuracy of the system is also relatively improved.3.The positioning signal generation module of TC-OFDM base station based on Zynq platform is designed.The layout methods of base stations in two different scenarios are verified by the system base station and the receiving terminal.The verification results show that the average positioning accuracy of the system can reach 0.65 meters in the case of no signal occlusion;the average positioning accuracy of the system in the presence of signal occlusion can reach 1.26 meters.