The plain text/csv file should be encoded in UTF-8! You can name the file whatever you like, but the file extension should be .clf
MCCMNC;CID;LAC;TYPE;LAT;LON;POS-RAT;DESC;SYS;LABEL;AZI;HEIGHT;HBW;VBW;TILT;LOC
Example line, each line is a unique cell of your cellular network:
26207;04002;00432;0;50.12345;-8.12345;-1;This is sector 3;3;4002_3;240;30.5;65;7;6;1599XY03