A cloudlet architecture using mobile devices

With the increasing ubiquity of mobile devices with computational capabilities comparable to many personal computers, they became the dominant personal computing devices nowadays. However, mobile devices still suffer short battery life and many of them are not capable of running rich-media, data-intensive and compute-intensive applications. Offloading to the cloud is a promising solution, however, long WAN latencies and the large amount of consumed energy using cellular data connectivity guided researchers to bring cloud capabilities to LANs to form cloudlets. On the other hand, in the last few years, there has been a new trend of making use of the computing resources of the vast amount of mobile devices available everywhere. In this paper, we introduce DroidCloudlet as a cloudlet architecture that is based on mobile devices. DroidCloudlet is empowered by available resource-rich mobile devices, while resource-constrained mobile devices can offload compute-intensive workloads to them. Offloading is carried out dynamically at runtime according to specific policies that target reducing execution time or saving energy. We also propose a lightweight cost model that is used to make offloading decision based on both context parameters and historical offloading performance results. To make use of all reachable mobile devices, we introduce a multilevel architecture in which offloading can bubble recursively from local cloudlet servers to other remote servers in any reachable cloudlet. For evaluation, we have built a prototype of the proposed architecture and performance results show that it succeeded to save up to 72% of execution time and 98% of consumed energy.