Patent Publication Number: US-2023161071-A1

Title: Method for distinguishing sunny-rainy weather based on time division long-term evolution network

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 202111184976.5, filed on Oct. 21, 2021, the contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The application relates to the field of meteorological detection, and in particular to a method for distinguishing sunny-rainy weather based on time division long-term evolution network. 
     BACKGROUND 
     Precipitation plays an extremely important role in the process of water cycle and energy cycle on the earth. The effective detection of precipitation information is of great significance to the early warning of natural disasters, agricultural production and traffic safety. At present, the professional ground-based rain gauge can accurately record the rainfall, but the sparse distribution limits the application of the observation results in a large scale. Weather radar can monitor the regional distribution of rainfall in a wide range, but Z-R (radar reflectivity factor-rainfall intensity) relationship will be affected by the local raindrop size distribution. Rain satellite can obtain the information of rainfall distribution around the world, but its spatial-temporal resolution is low and it is easily disturbed by clouds, so its ability to detect near-surface light rain is limited. 
     In addition to the above-mentioned professional meteorological instruments, non-cooperative electromagnetic wave sources widely distributed around the world can also be used for the detection of rainfall information. The most typical example is the rainfall information monitoring method based on commercial communication microwave link, which has the characteristics of sampling objects near the ground, high spatial and temporal resolution, and reflects the average condition of the path. In this method, the rain-induced attenuation information on the link is extracted by the level value recorded by the receiver, and the average rainfall intensity of the path is inversed by combining the International Telecommunication Union Radiocommunication Sector (ITU-R) rain-induced attenuation model. The rainfall information monitoring method based on this principle has been widely studied and applied in the world. However, at present, a large number of microwave backhaul links have been replaced by underground optical fibers, and less and less data of commercial communication microwave links are available in China, which greatly limits the popularization and application of rainfall information monitoring methods based on commercial communication microwave links in China in the future. 
     In addition to microwave backhaul links, in fact, non-cooperative signal sources that are more widely distributed are electromagnetic wave propagation networks formed between communication base stations and communication terminals, such as TD-LTE (Time-Division Long Term Evolution) network commonly used in 4G mobile phone communication. The communication electromagnetic wave frequency between 4G base station and mobile phone terminal is less than 3 GHz, and the microwave attenuation effect of rainfall is very weak in this frequency range, so it is difficult to extract the rain-induced attenuation first and then obtain the rainfall information like the microwave backhaul links. However, the measurement report provided by each TD-LTE network base station contains the counting information of multi-interval strength, quality and time delay of the terminal signal, which will change regularly when rainfall occurs, so the counting information has the potential to be applied to the monitoring of rainfall information in theory. 
     SUMMARY 
     The objective of the present application is to provide a method for distinguishing sunny-rainy weather based on time division long-term evolution network, so as to solve the problems existing in the prior art. 
     To achieve the above objective, the present application provides the following solutions. 
     The application provides a method for distinguishing sunny-rainy weather based on time division long-term evolution network, which includes the following steps: 
     constructing a sunny-rainy discrimination model, and inputting a sunny-rainy feature and a sunny-rainy label matrix into the sunny-rainy discrimination model for training; and 
     analyzing credibility of rainfall events in a coverage area of a base station based on the trained rain-sunny discrimination model. 
     Optionally, before constructing the sunny-rainy discrimination model, the method further includes: 
     selecting a plurality of normally working time division long-term evolution network base stations in a same area, and recording return information of communication terminals in each base station in a same statistical period; 
     calculating a number of return parameters in each value interval, a total number of returns and an average number of return parameters; 
     taking the number of the return parameters in each value interval, the total number of return parameters and the average number of return parameters as a communication measurement statistics; 
     carrying out the calculation above in a plurality of statistical periods, and summarizing a plurality of the communication measurement statistics as the sunny-rainy feature; and 
     constructing the sunny-rainy label matrix. 
     Optionally, the process of constructing the sunny-rainy label includes: 
     for a plurality of rain gauges in the same area, and judging whether there is a rainfall in the same statistical period based on an observation result of a rain gauge closest to a normally working time division long-term evolution network base station; and 
     taking a judgment result as the sunny-rainy label, making and recording the above judgment in a plurality of statistical periods, and summarizing a plurality of the sunny-rainy labels obtained as the sunny-rainy label matrix. 
     Optionally, the sunny-rainy labels are determined by taking an accumulated rainfall recorded by the closest rain gauge in space and a threshold value of 0.1 mm as a dividing standard. 
     Optionally, the process of constructing the sunny-rainy discrimination model includes: 
     constructing the sunny-rainy discrimination model based on machine learning binary classification, wherein the machine learning binary classification includes a bagged decision tree classification algorithm. 
     Optionally, the process of inputting the obtained sunny-rainy feature and sunny-rainy label matrix into the sunny-rainy discrimination model for training includes: 
     taking the observation results of multi-statistical periods, multi-base stations and multi-rain gauges in the area in the sunny-rainy feature as a training set, and inputting into the sunny-rainy discrimination model; and 
     conducting the training by identifying whether there is a rainfall event in the statistical period within the coverage area of the base station. 
     Optionally, the process of conducting the training by identifying whether there is a rainfall event in the statistical period within the coverage area of the base station includes: 
     comprehensively judging the probability of rainfall events in a certain position in the area based on the results of sunny-rainy discrimination of all communicable base stations in the position. 
     Optionally, the process of inputting the obtained sunny-rainy feature and sunny-rainy label matrix into the sunny-rainy discrimination model for training further includes: 
     testing the accuracy of the sunny-rainy discrimination model by ten-fold cross verification, and obtaining model performance indicators and a confusion matrix. 
     Optionally, the process of analyzing the credibility of rainfall events in the coverage area of the base station based on the trained sunny-rainy discrimination model includes: calculating a credibility of the rainfall based on an inverse distance weighting method. 
     The application discloses the following technical effects: 
     The application provides a method for distinguishing sunny-rainy weather based on time division long-term evolution network, which fully digs sensitive feature quantities of sunny-rainy periods on the basis of statistical results of time division long-term evolution network measurement reports, and realizes effective detection of rainfall information in a regional range; meanwhile, based on the widely existing time division long-term evolution network, the application provides a near-surface rainfall information monitoring means with ultra-low cost, wide coverage and high spatial resolution, and additional hardware cost investment is not needed, which has extremely high practical application prospect. The application may be used as a new method for identifying sunny-rainy period and applied to practical business. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without any creative effort. 
         FIG.  1    is a schematic diagram of the distribution of communication base stations, communication terminals and rain gauges in the embodiment of the present application, wherein BS represents communication base stations, RG represents rain gauges, and mobile phone icons represent communication terminals. 
         FIG.  2    is a working flow chart of a method for distinguishing sunny-rainy weather based on time division long-term evolution network in the embodiment of the present application, wherein the solid line represents the establishment process of a sunny-rainy discrimination model, and the dotted line represents the application process of the sunny-rainy discrimination model. 
         FIG.  3    is a confusion matrix of a single base station sunny-rainy discrimination model in the embodiment of the present application. 
         FIG.  4    is the calculation result of rainfall credibility at a certain position in the embodiment of the present application. 
         FIG.  5    describes the steps in the embodiment of the present invention, in which the communication measurement statistics of time division long-term evolution network base stations in a certain area are used to obtain the sunny-rainy feature, and a machine learning binary classification algorithm is combined to establish a sunny-rainy discrimination model to realize the identification of rainfall events covered by a single base station, and the credibility of rainfall events occurring at specific positions is comprehensively judged based on multiple base stations. 
         FIG.  6    describes the steps of obtaining the identification feature matrix of sunny-rainy weather based on the time division long-term evolution network base station in a certain area. 
         FIG.  7    describes the steps of establishing label matrix based on the observation results of rain gauge in the area. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all of them. Based on the embodiment of the present application, all other embodiments obtained by ordinary technicians in the field without creative labor are within the scope of the present application. 
       FIG.  1    is a schematic diagram of the distribution of communication base stations, communication terminals and rain gauges in the embodiment of the present application;  FIG.  2    is a working flow chart of a method for distinguishing sunny-rainy weather based on time division long-term evolution network in the embodiment of the present application;  FIG.  3    is a confusion matrix of a single base station sunny-rainy discrimination model in the embodiment of the present application;  FIG.  4    is the calculation result of rainfall credibility at a certain position in the embodiment of the present application. 
     According to the application, the communication measurement statistics of time division long-term evolution network base stations in a certain area are used to obtain the sunny-rainy feature, and a machine learning binary classification algorithm is combined to establish a sunny-rainy discrimination model to realize the identification of rainfall events covered by a single base station, and the credibility of rainfall events occurring at specific positions is comprehensively judged based on multiple base stations, which mainly includes the following steps (as shown in  FIGS.  5 - 7   ). 
     S 1 , obtaining the identification feature matrix of sunny-rainy weather based on the time division long-term evolution network base station in a certain area. 
     S 101 , selecting 116 normally working time division long-term evolution network base stations BS1, BS2, BS116 in the area, and each base station records the information returned by the mobile terminal in the s-th statistical period (statistical period T=60 (min)) (s=1, 2, . . . , 48); 
     S 102 , the m-th base station calculate the number of reference signal receiving power intervals n 1,m,s , n 2,m,s , . . . , n 48,m,s  (there are 48 intensity interval in total), the total sampling points N m,s  of reference signal receiving power and the average reference signal receiving power Ave m,s  according to the information returned by the mobile terminal; 
     S 103 , setting up the feature x m,s =[n 1,m,s , n 2,m,s , . . . , n K,m,s , N m,s , Ave m,s ] of sunny-rainy identification in the s-th statistical period of the m-th base station, and obtaining the feature matrix: 
     
       
         
           
             
               X 
               = 
               
                 
                   [ 
                   
                     
                       
                         
                           X 
                           1 
                         
                       
                     
                     
                       
                         
                           X 
                           2 
                         
                       
                     
                     
                       
                         … 
                       
                     
                     
                       
                         
                           X 
                           116 
                         
                       
                     
                   
                   ] 
                 
                 ⁢ 
                 
                   ( 
                   
                     
                       
                         X 
                         m 
                       
                       = 
                       
                         [ 
                         
                           
                             
                               
                                 x 
                                 
                                   m 
                                   , 
                                   1 
                                 
                               
                             
                           
                           
                             
                               
                                 x 
                                 
                                   m 
                                   , 
                                   2 
                                 
                               
                             
                           
                           
                             
                               … 
                             
                           
                           
                             
                               
                                 x 
                                 
                                   m 
                                   , 
                                   48 
                                 
                               
                             
                           
                         
                         ] 
                       
                     
                     , 
                     
                       m 
                       = 
                       1 
                     
                     , 
                     … 
                     , 
                     116 
                   
                   ) 
                 
               
             
             , 
           
         
       
     
     and normalizing X to obtain X′; 
     S 2 , establishing label matrix based on the observation results of rain gauge in the area. 
     S 201 , There is a rain gauge RG 1  in the area, and judging whether there is a rainfall in the s-th statistical period of the m-th base station according to the observation result of RG 1 , and using the judgment result as the sunny-rainy label y m,s : 
     
       
         
           
             
               y 
               
                 m 
                 , 
                 s 
               
             
             = 
             
               { 
               
                 
                   
                     
                       
                         1 
                         , 
                         
                           
                             if 
                             ⁢ 
                                 
                             
                               Acc 
                               
                                 
                                   RG 
                                   1 
                                 
                                 , 
                                 s 
                               
                             
                           
                           &gt; 
                           
                             0.2 
                                 
                             mm 
                           
                         
                       
                     
                   
                   
                     
                       
                         0 
                         , 
                         
                           
                             if 
                             ⁢ 
                                 
                             
                               Acc 
                               
                                 
                                   RG 
                                   1 
                                 
                                 , 
                                 s 
                               
                             
                           
                           ≤ 
                           
                             0.1 
                                 
                             mm 
                           
                         
                       
                     
                   
                 
                 , 
               
             
           
         
       
     
     wherein Acc RG     1     ,s  is the accumulated rainfall (mm) recorded by RG 1  in the s-th statistical period. 
     S 202 , Combining the sunny-rainy labels to obtain a label matrix: 
     
       
         
           
             Y 
             = 
             
               
                 [ 
                 
                   
                     
                       
                         Y 
                         1 
                       
                     
                   
                   
                     
                       
                         Y 
                         2 
                       
                     
                   
                   
                     
                       … 
                     
                   
                   
                     
                       
                         Y 
                         116 
                       
                     
                   
                 
                 ] 
               
               ⁢ 
               
                 
                   ( 
                   
                     
                       
                         Y 
                         m 
                       
                       = 
                       
                         [ 
                         
                           
                             
                               
                                 y 
                                 
                                   m 
                                   , 
                                   1 
                                 
                               
                             
                           
                           
                             
                               
                                 y 
                                 
                                   m 
                                   , 
                                   2 
                                 
                               
                             
                           
                           
                             
                               … 
                             
                           
                           
                             
                               
                                 y 
                                 
                                   m 
                                   , 
                                   S 
                                 
                               
                             
                           
                         
                         ] 
                       
                     
                     , 
                     
                       m 
                       = 
                       1 
                     
                     , 
                     … 
                     , 
                     116 
                   
                   ) 
                 
                 . 
               
             
           
         
       
     
     S 3 , Constructing the training set [X′, Y] according to the historical data, and the classification algorithm of bagged decision tree is combined to establish a sunny-rainy discrimination model to identify whether there is a rainfall event in a statistical period within the coverage of a base station. 
     S 4 , Testing the accuracy of the sunny-rainy discrimination model by ten-fold cross verification, and obtaining the model performance indicator and confusion matrix. 
     S 5 , in practical application, taking a specific location O as an example, comprehensively judging the probability of rainfall events in this location according to the results of sunny-rainy discrimination of all communicable base stations in the area. The number of all communicable base stations in location O is a=3, and the number of communicable base stations judged as rainy period in a certain statistical period is b. Calculate the credibility of rainfall events in this location in this statistical period according to the inverse distance weighting: 
     
       
         
           
             
               credibility 
               = 
               
                 
                   
                     ∑ 
                     
                       j 
                       = 
                       1 
                     
                     b 
                   
                     
                   
                     d 
                     
                       rain 
                       , 
                       j 
                     
                     
                       - 
                       2 
                     
                   
                 
                 
                   
                     ∑ 
                     
                       i 
                       = 
                       1 
                     
                     3 
                   
                     
                   
                     d 
                     
                       all 
                       , 
                       i 
                     
                     
                       - 
                       2 
                     
                   
                 
               
             
             , 
           
         
       
     
     where d rain,j  (km) is the distance between the j-th communicable base station judged to be in the rainy period and this location, and d all,i  (km) is the distance between the i-th communicable base station and this location. The calculation results are shown in  FIG.  4    and Table 1. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 d all, 1   
                 d all, 2   
                 d all, 3   
                 y 1, s   
                 y 2, s   
                 y 3, s   
                 d rain, 1   
                 d rain, 2   
                 d rain, 3   
                 credibility 
               
               
                   
               
             
            
               
                 2 km 
                 1.5 km 
                 1 km 
                 1 
                 1 
                 1 
                 d all, 1   
                 d all, 2   
                 d all, 3   
                 1.00 
               
               
                   
                   
                   
                 1 
                 1 
                 0 
                 d all, 1   
                 d all, 2   
                 — 
                 0.41 
               
               
                   
                   
                   
                 1 
                 0 
                 1 
                 d all, 1   
                 d all, 3   
                 — 
                 0.74 
               
               
                   
                   
                   
                 1 
                 0 
                 0 
                 d all, 1   
                 — 
                 — 
                 0.15 
               
               
                   
                   
                   
                 0 
                 1 
                 1 
                 d all, 2   
                 d all, 3   
                 — 
                 0.85 
               
               
                   
                   
                   
                 0 
                 1 
                 0 
                 d all, 2   
                 — 
                 — 
                 0.26 
               
               
                   
                   
                   
                 0 
                 0 
                 1 
                 d all, 3   
                 — 
                 — 
                 0.41 
               
               
                   
                   
                   
                 0 
                 0 
                 0 
                 — 
                 — 
                 — 
                 0.00 
               
               
                   
               
            
           
         
       
     
     In the practical application process, according to the feature extracted from the time division long-term evolution network measurement report, the sunny-rainy label of single base station coverage and the comprehensive judgment result of rainfall credibility of multi-base station intersection area can be directly obtained. 
     The above shows and describes the basic principle, main features and advantages of the present application. It should be understood by those skilled in the art that the application is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions only illustrate the principles of the application. Without departing from the spirit and scope of the application, there will be various changes and improvements of the application, all of which fall within the scope of the claimed application. The scope of that application is defined by the appended claim and their equivalents.