Optimal Cloudlet Placement and User to Cloudlet Allocation in Wireless Metropolitan Area Networks

Mobile applications are becoming increasingly computation-intensive, while the computing capability of portable mobile devices is limited. A powerful way to reduce the completion time of an application in a mobile device is to offload its tasks to nearby cloudlets, which consist of clusters of computers. Although there is a significant body of research in mobile cloudlet offloading technology, there has been very little attention paid to how cloudlets should be placed in a given network to optimize mobile application performance. In this paper we study cloudlet placement and mobile user allocation to the cloudlets in a wireless metropolitan area network (WMAN). We devise an algorithm for the problem, which enables the placement of the cloudlets at user dense regions of the WMAN, and assigns mobile users to the placed cloudlets while balancing their workload. We also conduct experiments through simulation. The simulation results indicate that the performance of the proposed algorithm is very promising.

1 Introduction

Mobile applications are becoming increasingly computation-intensive, while the computing capacity of mobile devices are limited due to their portable sizes. A powerful approach to improving the performance of mobile applications is to offload some of their tasks to remote clouds, where an application consists of multiple tasks. Existing research in mobile task offloading mostly considered the cloud to be the remote offloading destination, due to its abundance of computational resources. However, the cloud usually is remotely located and far away from its users, and the network delay incurred by transferring data between users and the cloud can be very costly. This is especially undesirable in reality-augmenting applications and mobile multiplayer gaming systems, where a crisp response time is critical to the user’s experience. Recent works [1], [2] have proposed the use of clusters of computers called cloudlets as a supplement to the cloud for offloading. Cloudlets are typically collocated at an access point (AP) in a network, and are accessible by users via wireless connection. A key advantage of cloudlets over the cloud, is that the close physical proximity between cloudlets and users enables shorter communication delays, thereby improving the user experience of interactive applications.