Efficient and Transparent Dynamic Content Updates for Mobile Clients

Trevor Armstrong, Olivier Trescases, Cristiana Amza, Eyal de Lara

4th International Conference on Mobile Systems, Applications, and Services (MobiSys), Uppsala, Sweden, June 2006



We introduce a novel infrastructure supporting automatic updates for dynamic content browsing on resource constrained mobile devices. Currently, the client is forced to continuously poll for updates from potentially di erent data sources, such as, e-commerce, on-line auctions, stock and weather sites, to stay up to date with potential changes in content. We employ a pair of proxies, located on the mobile client and on a fully-connected edge server, respectively, to minimize the battery consumption caused by wireless data transfers to and from the mobile device. The client speci es her interest in changes to speci c parts of pages by highlighting portions of already loaded web pages in her browser. The edge proxy polls the web servers involved, and if relevant changes have occurred, it aggregates the updates as one batch to be sent to the client. The proxy running on the mobile device can pull these updates from the edge proxy, either on-demand or periodically, or can listen for pushed updates initiated by the edge proxy. We also use SMS messages to indicate available updates and to inform the user of which pages have changed. Our approach is fully implemented using two alternative wireless networking technologies, 802.11 and GPRS. Furthermore, we leverage our SMS feature to implement and evaluate a hybrid approach which chooses either 802.11 or GPRS depending on the size of the update batch. Our evaluation explores the data transfer savings enabled by our proxy-based infrastructure and the energy consumption when using each of the two networking capabilities and the hybrid approach. Our results show that our proxy system saves data transfers to and from the mobile device by an order of magnitude and battery consumption by up to a factor of 4.5, compared to the client-initiated continuous polling approach. Our results also show that the batching e ect of our proxy reduces energy consumption even in the case where the user never visits the same page twice.