The unheralded power of cloudlet computing in the vicinity of mobile devices

With the popularity of smartphones and explosion of mobile applications, mobile devices are becoming the prevalent computing platform for convenient communication and rich entertainment. Because mobile devices still have limited processor power, computing-intensive applications need to be offloaded to either remote clouds or nearby cloudlets for processing. But, remote cloud computing is hindered by the long latency and expensive roaming charges of cellular radio access. Therefore, cloudlet computing becomes appealing to provide instant and low-cost service through resource-rich devices (e.g., desktops) in the vicinity of mobile devices. It is evident that cloudlet computing is challenged by the intermittent connection between cloudlets and mobile devices due to user mobility. The question is how to evaluate the impact of user mobility on cloudlet computing performance. In this paper, we examine the cloudlet access probability, task success rate, and task execution speed to measure the impact of mobility. We discover that the cloudlet access probability is μTc /(μT1 + μTc) determined by mean connection time μTc and mean inter-connection time μT1 between the mobile device and the cloudlet. Furthermore, we find that the task success rate and execution speed depend on not only task computation demand and cloudlet computing speed but also cloudlet access probability. Our findings reveal that the ratio μTc /(μT1 + μT c) quantifies the impact of node mobility on both cloudlet access probability and cloudlet computing performance.