© 2014 IEEE. Femtocells are small cellular base-stations, suitable for residential units or business offices. Femtocells are cost-effective solution for areas where deploying traditional base-stations is costly. Femtocells inherits security and privacy threats of GSM, and UMTS networks such as location privacy and tracking. These threats are even more severe, since the deployment of femtocells, which covers areas as small as an office, allows for an unprecedented tracking of mobile users location. This paper presents an authentication scheme, which allows a mobile user to use an open femtocell, while making it hard for its mobile operator to know the exact location of that mobile user. The scheme complements the privacy protection of UMTS. Further, the scheme enables mobile operators to reward owners of open femtocells. The paper discusses the security of the presented scheme. The simulation of the authentication scheme shows the feasibility of our work.