GPS-tag for indoor location information and additional user information providing

Today the number of smartphone users is rapidly increasing and smartphone market is expected to reach 26% of total mobile phone market in 2011. Also the number of LBS (Location-based service) providers grew more than ten times over the year in South Korea, reflecting rising demand for LBS-based applications on smartphones. User can have relatively good locationing performance with the built-in GPS receiver of Smartphones, which is one of major resource for location information in outdoor environments. However, user can´t get a fine LBS service in indoor environment because the GPS system does not work reliably since its signal suffers from the attenuation, reflection and refraction from buildings and walls. This paper presents a novel method to provide location information and user defined additional information with the GPS-tag to a smartphone whose built-in GPS receiver is idling in indoor and shows a signal structure and system design aspects of GPS-tag.