DETERMINING THE PREFERENCE OF GSM OPERATORS IN TURKEY WITH FUZZY TOPSIS AFTER MOBILE NUMBER PORTABILITY SYSTEM APPLICATION

Mobile number portability systems is a system that can allow portability of GSM (Global System for Mobile Communications) number from another operator without changing GSM number. There are several criteria to select the GSM operators by customer after this system is legal in Turkey. The main purpose of this study is to determine the market sharing in the future of GSM operators by expressing the weighting grades of selection criteria and the relationship between criteria and alternatives that include uncertainty as fuzzy triangular numbers. In this study, the selection criteria of GSM operators are defined form literature and views of customer and weighted with linguistic variables by working group. Avea, Turkcell and Vodafone that active in Turkey are graded with linguistic variables to each criterion. Analyzing linguistic variables as qualitative variables and using graded linguistic variables in a specified interval are required fuzzy multi-criteria decision making methods. Expected market sharing of GSM operators is determined by using fuzzy TOPSIS method.