| Summary: | 碩士 === 國立中山大學 === 資訊工程學系研究所 === 88 === Due to the availability of the cellular phone, PCS (Personal Communication Service) has become wildly popular world-wide [1], and the number of the PCS users has quickly grown beyond what anyone had imagined. As its name indicates, mobility is the most remarkable feature of a cellular phone. On the other hand, that means it is difficult to determine the location of the PCS users. The proficiency to determine the geographical position of a cellular phone users have become increasingly important. One main reason for this service is the use of mobile phones for emergency calls, which is expected to grow quickly in the near future. For emergency assistance via 911 (Emergency 911, E-911), the FCC (Federal Communications Commission) has now required that system operators of mobile communications networks be able to accurately locate mobile callers before year 2001. There has been a lot of ongoing research examining cellular positioning options among cellular and PCS providers. Most location approaches require measurements at multiple receiving stations or need supports from base stations.
Our main proposal in this paper is a new approach to enhance the performance of wireless position location through a single cellular phone. This method has the following two features: First, it does not require any modification to the current GSM (Global System for Mobile Communication) architecture, that is, it does not increase network traffic. Second, the location identifications is performed on the mobile end, which does not increase computation load of the network system. Hence, the quantity of self-location cellular phones which can be supported by GSM system has no upper limit. In this sense, we would say that Cell Base Automatic Location Identification System is a method worthy of further exploration. Meanwhile, this technique could be applied on the other domains, such as electron-map, local resource detected, newfangled chat room, controlling caller’s location, etc.
The intention of this paper is to introduce innovation uses single cellular phone to implement ALI (Automatic Location Identification) system. The whole issue determining the TA (Timing Advance) between the MS (Mobile Station) and the BTS (Base Transference Station) as well as coupling the calculated distance with the determined direction of the BTS signal so as to calculate the location of the MS. To counter the inaccuracies of the ALI system, we offer a force-handover subfunction. Even though one or more force-handovers increase the accuracy, the cost is extra time overhead.
In our location system, we implement two applications to determine the reliability of any ALI system information. They are Wireless Signed System and Resources Information Searching System.
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