Locating Mobiles Essay Example | Topics and Well Written Essays - 2500 words

Locating Mobiles - Essay Example If accurate movement prediction per mobile was possible, the task of locating mobiles given their last location would become substantially efficient in terms of both speed and system resources used. Being able to determine the mobile's future locations and access points as it moves inside the network while being connected can result in significant improvement in system efficiency and connection quality. The wireless terminal (laptop or PDA) is equipped with an IEEE 802.11b -compatible network card and a web browser. The web server handles the presentation logic. The application and location servers' constitute the application logic. One possible solution for improving the quality of the service is to use a vector image format. The use of vector data is essential, in order to improve the response time and the power of the client application. Using a vector format, there is no need to request a new image file every time the user zooms or pans the image or something changes in that particular image. At present, the most promising vector format for Internet-use is SVG, which is a W3C recommendation for describing dynamic and interactive two-dimensional graphics in XML. These graphics can contain vector graphic shapes, raster images and text. SVG is ideal for visualising geographical information on the Web, since it has many features that are used in traditional cartography such as polygons, lines, points and text. More sophisticated features suitable for mapping in SVG include layering, opacity, gradient fills, stroke options, clipping, masking, scripting, animations and filter effects. SVG can also handle coordinate transformations and enables high quality paper prints. In addition, SVG maps are freely pannable and zoomable. Cellular Location Methods Cellular location methods use the signals of the cellular system to find the location of a mobile station. Since cellular systems were not originally designed for positioning, the implementation of different location methods may require new equipment to make the necessary measurements for location determination and new signalling to transfer the measurement results to the location determination unit. Before presenting the cellular location methods and their implementation aspects, some concepts that will be used to classify different methods based on the role of the mobile station (MS) and the network or on the location measurement principle are defined. Based on the functions of the MS and the network, implementation of a location method belongs to one of the following categories: Network-based Mobile-based Mobile-assisted In network-based implementation one or several base stations (BSs) make the necessary measurements and send the measurement results to a location center where the position is calculated. Network-based implementation does not require any changes to existing handsets, which is a significant advantage compared to mobile-based or most mobile-assisted solutions. However, the MS must be in active mode to enable location measurements and thus positioning in idle mode is impossible. In mobile-based implementation the MS makes measurements and position determination. This allows positioning in idle mode by measuring control channels, which are continuously transmitted. Some assisting information, e.g. BS