Research On Optimization Of Electrically Tunable Antenna's Downtilt Based On The Firefly Algorithm

With the rapid development of mobile communication technology,the increasing demand for network capacity and the efficient utilization of network resources become the urgent problem for wireless industry.For 2G,3G,4G or 5G networks,a reasonable base station antenna selection and downtilt adjustment are essential ways to improve the performance of the cellular network.Therefore,this paper proposes to optimize the downtilt of an electrically tunable antenna based on the firefly algorithm to improve the network performance of the cellular network system.The research mainly includes the following contents:1.Mathematical model of downtilt of electrically tunable antenna.Firstly,the cellular network 3×1 sector partition model and base station antenna's downtilt model is established,the vertical antenna gain is approximated by the Taylor series expansion using the characteristics of the cdegree of freedom of the vertical dimension of the antenna.Then according to the approximate antenna gain and the path loss model derived the formula of signal to interference plus noise ratio(Signal to Interference plus Noise Ratio,SINR),the relationship between antenna's downtilt and system optimization objective function is obtained,and the definition of optimization problem is realized2.Principles of the standard firefly algorithm.According to the luminescence properties of the firefly populations in nature,from the four aspects of bionics algorithm,parameter definition,parameter analysis and optimization process to analyze the firefly algorithm to search the optimal.Through simulation analysis,the effects of different values of population size,intensity absorption coefficient and step size factor on the optimization speed,convergence accuracy and global optimization search of the standard firefly algorithm are described..3.Research and analysis of improved firefly algorithm.Aiming at the problem of low convergence precision and local optimization search which is easy to occur at the end of the optimization of the firefighting algorithm,the algorithm is improved and the influence of the key parameters on the algorithm is proposed based on the inertia weight,the convergence factor and chaotic mapping.By simulating the multivariate classical peak test function,the optimization ability of the standard algorithm and the improved algorithm in solving the problem to be solved is described,which shows that the improved algorithm is efficient.4.Research on optimization of downtilt of electrically tunable antenna.When using the firefly algorithm to optimize the base station sector antenna's downtilt in the cellular network,taking into account the large amount of information needed to optimize the multiple antenna's downtilt in the global scope,and the algorithm implementation also has high complexity,proposed a distributed optimization method to jointly optimize all the sector antenna's downtilt.In addition,considering the special situation of independent optimization of the cell,the scheme of the adjustment scheme based on the single cell antenna's downtilt optimization is given as a supplementary explanation of the optimization of the downtilt of electrically tunable antenna.