Research Of Indoor Location Based On Radio-Over-Fiber Distributed Antenna System

Recently, the demand of location-aware services is emerging and growing rapidly. The research of indoor location system has significant application values and business prospects. Radio-over-fiber distributed antenna system (RoF-DAS) is considered as a promising candidate particularly for in-building and indoor applications where the wireless propagation environment is challenging due to its advantageous architecture composed of centralized control center, broadband transparent fiber transmission, and cost-effective distributed remote antenna units. Therefore, it is of great significance to conduct research of indoor location based on RoF-DAS.Firstly, we introduced the generation and development of indoor location technology, analyzed pros and cons of traditional indoor location technology algorithm, and summed up key factors affecting indoor location accuracy. According to the characteristics of the indoor wireless environment, we focused on analyzing the merits of RoF-DAS in the application of indoor location.In specific research of indoor location system based on RoF-DAS, first of all, we introduced indoor location scheme combing RoF-DAS and radio frequency identification (RFID) technology and analyzed its system architecture, location method and specific application scenarios. Then we proposed a novel indoor location scheme combing WLAN and RFID. It is known that wallboard attenuation is the main source of indoor location error. We theoretically analyzed the process of electromagnetic signals through wallboard, and finished the simulation and experiments to verify that different frequency signals through the same wall with different attenuation. Therefore, we can use dual frequency signals to automatically detected and dynamically modified traditional wireless indoor propagation model, and then used three steps to conduct indoor location. Because we used dual frequency signals, we analyzed the link performance of dual frequency signals transmitted in RoF-DAS system with experiments. Further we validated the effectiveness and reliability of this dual frequency scheme.Finally, according to the different characters of increasingly complex and diverse indoor scenarios, such as libraries, airports and warehouses, we proposed different indoor location solutions based on RoF-DAS for three typical indoor scenarios.