| Summary: | 碩士 === 育達商業技術學院 === 資訊管理所 === 97 === The objective of this research discusses how to increase positioning accuracy that based on the low positioning system complexity. To realize this objective, this research focus on the measurements available for the implementation of handset positioning in a wireless cellular network based on the cellular system standards Cell Identity (CI) and strength of signals received by the handset. The Received Signal Strength (RSS) method is one of the handset positioning technologies that is straightforward and simple implement. Either RSS measurement was used the propagation prediction model that converted to the distance between handset and Base Station (BS), which contours around BSs is circle. Three measurements are known, the position of a handset can be determined as the unique intersection point of threes circles if the estimated distance is accuracy. Due to an environment-dependent propagation prediction model for the dependence of RSS on BS-handset distance should be used. If the application of this model is not correct in the surrounding environment characteristic, then, the environment-dependent term within model cause the prediction errors in distance estimates and consequently in position estimates.
This work contributes the differential principle on RSS to overcome the prediction errors for the position estimation. The difference of Received Signal Strength can calculate the difference in a pair of RSSs from a set of RSSs received by the handset. Therefore, this process can eliminate prediction errors in distance estimates.
This study investigates the Difference of Signal Strength (DSS) technology in the Global System for Mobile Communication (GSM) system. The effect of shadowed mobile radio environments, and configuration and number of BSs on the accuracy of the DSS technology is also studied. Finally, the trial tests in a GSM network, based on circular positioning method and hyperbolic positioning method, are performed with various environments to show that the estimated positioning error is from 56.78m to 82.68m by using circular positioning method.
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