Metric and control of system fairness in heterogeneous networks

System fairness has been regarded as an important performance index related to qualities of services in mobile networks. Most of researches evaluate the fairness of a cellular system in terms of the cumulative distribution function (CDF) of user throughputs. However, it's difficult to treat the CDF as a parameter to set, adjust and compare. This paper proposes Gini coefficient, which is a primary measure of the inequality of income in economics, can be developed to represent the system fairness in mobile networks. Furthermore, we present a scheme with modified genetic algorithm (GA) to achieve certain level of the system fairness by adjusting the almost blank subframe (ABS) arrangement in LTE-Advanced heterogeneous networks (HetNets). Validations and numerical analysis on the relationship between the system throughput and fairness are performed by computer simulations.