Research On The Construction Methods Of Radio Environment Map

Radio Environment Map,a comprehensive database which can process and store the multi-domain information of radio scenarios,has been adopt and referenced by standard documents like IEEE,ITU-R,ETSI and acknowledged to be an essential enabling module of wireless communication networks in the future.Radio Environment Map provides effective information support of Cognitive Radio devices and networks and improves the performance of them.On the other hand,as a supporting tool to solve the imbalance problems of spectrum resources and realize the spectrum sharing,Radio Environment Map makes the spectrum resources visible,which would serve as a dynamic management method for radio management department.This paper focus on the construction of Radio Environment Map by spatial interpolation techniques based on field measurements.The main research content are listed as follows:First,through the tracking of numerous relevant papers and project reports,this paper presents the background,purpose,and worth of Radio Environment Map,introduces its concepts,application area,and key techniques exhaustively,lays a solid foundation of whole research;Second,selecting the third floor of School of Information Science and Engineering in Yunnan University as the experimental area,this paper constructs the Wi-Fi radio environment map indoor by indirect method using Inverse Distance Weighting interpolation.Based on the research of transmitter location and power estimation based REM construction method.Comparing to the traditional Inverse Distance Weighting interpolation,the algorithm of this paper reduces its mean absolute error for 1.8768 dB when interpolating power dexp=1 and 4.354 dB when dexp=2 by modifying the estimation methods and weights distribution.Third,selecting the whole campus of Yunnan University as the experimental area,this paper constructs the FM radio environment map by direct method using Kriging interpolation.During the research,this paper chooses spherical model as the theoretical model of Kriging semi-variogram which is adaptive to the radio environment,fits the experimental semi-variogram by Ant Colony Optimization algorithm which searches the ideal solutions by optimize the coefficients through iterations.Comparing to the traditional least mean square fitting,this method reduces the mean absolute error by 1.0853 dB.To sum up,based on the field-measured data of radio signal,this paper has completed the construction of radio environment map by Spatial Interpolation algorithm,and the results vividly shows the real state of radio environment in a certain area.Through the modification of algorithm,this paper improves the precision of Spatial Interpolation,and experiments have shown the obvious improvement.