In recent years, smart phones and wireless internet usage are remarkably increased. It is known that citizens reside in indoors more than 80 percent of daily life. The indoor positioning technologies have been recognized as the core technology for their safety, management, and location-based service. Most shopping complex have installed Wi-Fi access points (APs) for providing internet service to the customers. In this paper, an implementation of real-time indoor positioning scheme based on radio signal strength (RSS) value of Wi-Fi AP is presented and the issues of implantation are discussed with the experiment results. Although there is estimation error, the estimated position of the smart phone can be displayed on the smart phone in real-time