| Summary: | 碩士 === 國立虎尾科技大學 === 電機工程研究所 === 101 === In recent year, research of joint wireless sensor networks (WSNs) and Context-Aware Service has drawn much interest. Context-aware service is a computing technology which incorporates information about the current location of a mobile user to provide more relevant services to the user. Therefore, the location of the user location is very important. Many studies have been conducted on the topics by using Wireless Fidelity (Wi-Fi), Bluetooth, and ZigBee technologies.
This thesis uses the RSSI value in the ZigBee WSN to calculate position to achieve context-aware service. ZigBee is a low-speed and short-range wireless network transmission protocol. The ZigBee wireless standard enables broad based deployment of wireless mesh networks with low cost, low power solutions providing the ability for devices to run for years on inexpensive batteries in a typical monitoring application. These features are suitable for our uses in the thesis. Currently, location and tracking algorithm for indoor positioning use a wireless received signal strength indicator (RSSI) or Link Quality Indicator (LQI) to implement. Since measurement of the RSSI value does not require additional hardware and is easy to implement, RSSI is used in this thesis to estimate the position of the object. In order to reduce the case of node failure, ZigBee sensor nodes typically use low energy consumption technology. Therefore, the transmission distance is often constrained severely. This thesis hopes to solve the problem of insufficient transmission distance. Thus, we propose to use the mobile data collection device to collect each node and aggregate data to the PC side. We use RSSI indicator of each nodes to judge the relative position of this mobile sink to make context-aware services.
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