Issue No.01 - January (2011 vol.10)
Ahmad Rahmati , Rice University, Houston
Lin Zhong , Rice University, Houston
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TMC.2010.139
Context information brings new opportunities for efficient and effective system resource management of mobile devices. In this work, we focus on the use of context information to achieve energy-efficient, ubiquitous wireless connectivity. Our field-collected data show that the energy cost of network interfaces poses a great challenge to ubiquitous connectivity, despite decent availability of cellular networks. We propose to leverage the complementary strengths of Wi-Fi and cellular interfaces by automatically selecting the most efficient one based on context information. We formulate the selection of wireless interfaces as a statistical decision problem. The challenge is to accurately estimate Wi-Fi network conditions without powering up the network interface. We explore the use of different context information, including time, history, cellular network conditions, and device motion, to statistically estimate Wi-Fi network conditions with negligible overhead. We evaluate several context-based algorithms for the estimation and prediction of current and future network conditions. Simulations using field-collected traces show that our network estimation algorithms can improve the average battery lifetime of a commercial mobile phone for an ECG reporting application by 40 percent, very close to the estimated theoretical upper bound of 42 percent. Furthermore, our most effective algorithm can predict Wi-Fi availability for one and ten hours into the future with 95 and 90 percent accuracy, respectively.
Network architecture and design, local and wide-area networks.
Ahmad Rahmati, Lin Zhong, "Context-Based Network Estimation for Energy-Efficient Ubiquitous Wireless Connectivity", IEEE Transactions on Mobile Computing, vol.10, no. 1, pp. 54-66, January 2011, doi:10.1109/TMC.2010.139