Location Assisted Wi-Fi Discovery On Mobile Devices For Energy Saving

Currently, mobile devices are already became more and more important to people. And they have already been shipped with faster processors, more memory, multiple radio interfaces, and powerful operating systems (OS), and, consequently, heavier applications. Moreover, specialized operating systems have been developed for handheld devices. Microsoft's Windows Mobile, and Google's Android are example operating systems designed for mobile devices. Out of question, mobile devices are now in the time with high-speed development.However, there is a gap between battery energy density and the overall system performance required by evolving cellular and consumer portable devices. This is because computing and communication capabilities of handheld devices have increased by orders-of-magnitude in the past two decades, battery energy density has only tripled in the same period of time. In this problem, there are many research directions. Such as efficient graphical user interface (GUI) design, reducing the energy cost of programs at the coding and compilation level and so on. Our scheme allows the mobile device to intelligently switch to the Wi-Fi interface when he or she needs high bandwidth. Therefore, it avoids the long periods in idle state and greatly reduces the numbers of unnecessary Wi-Fi scans on the mobile device.The main research work of the thesis contains the following aspects:We analyzed the researching level about mobile devices at present, especially the energy saving on communication; summarized the mobile devices'energy consumption and characteristic; analyzed the different locating modes'characteristic; proposed the scheme to save energy consumption by location information; in the situation of Indoor, we did much simulation with OMNeT++, and compared with other schemes; in the situation of outdoor, we did much experiments on the X876 Android mobile device. Our experiments demonstrate that the scheme effectively saves energy for mobile device integrated with Wi-Fi and cellular interfaces.This thesis also puts forward the direction of further study. We pointed out that the mobile devices'energy saving is a system level problem that needs to integrate individual energy saving techniques and strategies, while satisfying user's need. The scheme could be extended, and more computing could be moved to the cloud to save the energy.