| Popis: |
In the past several years, personal mobile devices have developed rapidly as versatile computing platforms, capable of installing and running many different applications. Often, these devices are equipped with multiple (wireless) network interfaces supporting internet access through one or more networks. The availability of these networks is dynamic over time, because the device owners move in and out of range during their daily activities: a device may connect to an ultra-wideband access point at home, simultaneously use a Bluetooth network and a cellular network while traveling, and connect to an 802.11 wireless local area network (WLAN) at work. Applications on mobile devices therefore experience intermittent connectivity or fluctuations in available throughput capacity when communicating with other nodes on the internet. Mobile applications may benefit from taking into account aspects of these dynamics – for instance, by adapting data rates to maximum available capacity or controlling when to scan and activate specific networks. Furthermore, they may provide a better service to the user when taking into account in a proactive manner the availability of these networks over time. This dissertation covers two aspects that are important for applications dealing with dynamic network resources on personal mobile devices. We define (1) a mechanism that provides applications with awareness of and control over current resources in a comprehensive, cross-layer way, and (2) we describe an approach to predict the future time of the occurrence of a network resource event, such as getting into range or moving out of range of a particular network, using traces of resource availability in the past. |
