Indoor location recognition method using RSSI values in system with small wireless nodes

Recent advances in information communication technologies will yield new systems/devices for the visually impaired. To realize such systems/devices, location information is essential, especially for indoor application. This paper proposes an indoor location estimation method that uses cost-effective radio frequency nodes. The proposed method uses received signal strength values to estimate the distance from the user node to several surrounding access points (AP). An experiment is conducted using commercial devices that are small and cost effective. The results show that location error can exceed 2 m if no AP is closer than 5 m to the node. If the user node is surrounded by 10 APs, three of which are used in location estimation, location error can be reduced to 0.7 m. These results verify the feasibility of the proposed system.