UNIT 3 MOBIL;E AND PERVASIVE COMPUTING NOTES

MOBILE AND PERVASIVE COMPUTING Large networks of simple sensors Usually deployed randomly Very prone to failures Use broadcast paradigms to communicate with other sensors Collect information and send it to base station Must focus on power conservation, instead of QoS. Energy=distance2 Static: once deployed do not change. Dynamic: could move by themselves or by an external agent. Motivation: Future ‘pervasive applications’ need to adapt the variations of context of execution, change of locations, change of devices, change of hardware resources of devices, and so on Recent research efforts focused on designing new mobile middleware systems capable of supporting mobility Apart from mobility, pervasive middleware will need to operate under above-mentioned conditions of a radical change Few contemporary researches have indeed focused on some of these requirement A qualitative difference between intended requirements and practical achievements still remains there Context awareness Research challenge will be that N classes of applications will have to adopt M numbers devices (N-to-M) instead of doing a single new application to a group of devices (1-to-M) Context (or extension) with respect to an application is to bind and re-bind a number of pervasive devices to facilitate the continuity of applications running on Example: In projects-RCSM, Lime, Tspaces- task components interact with services by sharing a tuple space or an event service or data-oriented services Designed for sensor networks where an end-user wants to remotely monitor the environment. Where the data from the individual nodes must be sent to a central base station, often located far from the sensor network. Desirable properties for protocols on these networks: Use 100’s – 1000’s of nodes Maximize system lifetime Maximize network coverage Use uniform, battery operated nodes The use of distributed cluster formation and local processing to reduce global communication along with randomized rotation of the cluster-heads allows LEACH to achieve the desired properties while being energy-efficient. Designed for sensor networks where an end-user wants to remotely monitor the environment. Where the data from the individual nodes must be sent to a central base station, often located far from the sensor network. Desirable properties for protocols on these networks: Use 100’s – 1000’s of nodes Maximize system lifetime Maximize network coverage Use uniform, battery operated nodes The use of distributed cluster formation and local processing to reduce global communication along with randomized rotation of the cluster-heads allows LEACH to achieve the desired properties while being energy-efficient. A combination of infrastructure and client meshing. Infrastructure provides connectivity to other networks such as the Internet, Wi-Fi, WiMAX, cellular, and sensor networks; Mesh clients can access the network through mesh routers as well as directly meshing with other mesh clients. The routing capab