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Next Generation Wireless Applications: Creating Mobile Applications in a Web 2.0 and Mobile 2.0 World, 2nd Edition by Paul Golding

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13.4 ACCURACY OF LOCATION-BASED SERVICES (LBS)

Returning to the methods of location finding, a major concern for any service or application is the accuracy of the location-finding process. Perhaps more important, is not just the accuracy, but also the consistent quality of location finding to a certain minimum level of guarantee, otherwise it is difficult to envisage a service where the user has to suffer hit-and-miss performance.

Figure 13.12 shows some of the problems associated with cell-based ID. Cell boundaries do not follow the neat honeycomb structure suggested by an idealised explanation of cellular systems. The edges suffer distortion due to the irregular physical topology of the cell and its physical influence on the strength of the RF signal throughout the area. Cells also overlap, as they are required to so to a certain degree in order for mobiles to smoothly handover from one cell to another as they move around the network area.

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Figure 13.12 Uncertainty of location based on cell boundaries.

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Figure 13.13 Uncertainties in cell size can distort location finding.

Figure 13.13 gives us an indication of the affect that cell uncertainty could have. Let's say our user urgently needs to use a temporary office facility (such as the Regus chain in the United Kingdom), probably ...

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