April / June 2016
Cloud-Link: Special Issue on Cloudlets
Recently, there has been considerable interest in using cloudlets for supporting mobile cloud computing services. Situated between a central cloud and mobile terminals, cloudlets are lightweight components with basic cloud computing functions to facilitate the provision of mobile cloud computing services. This issue of Cloud-Link is about cloudlets, for which seven recent articles have been selected to cover different aspects.
As mobile terminals have limited processing capability, offloading plays an important role in mobile cloud computing. Both the articles “On the Computation Offloading at Ad Hoc Cloudlet: Architecture and Service Modes” and “Offloading in Mobile Cloudlet Systems with Intermittent Connectivity” studied offloading issues in cloudlet-based systems. Cloudlets can be used to support multimedia service. The article “In-Network View Synthesis for Interactive Multiview Video Systems” investigated how to provide a multiview video system with the assistance of cloudlets. The article “PacketCloud: A Cloudlet-Based Open Platform for In-Network Services” studied the use of cloudlets at the network layer. It presents an open platform to provide in-network services using cloudlets. The article “Toward Vehicle-Assisted Cloud Computing for Smartphones” studied the integration of the infrastructure-based cloud and vehicular cloud based on cloudlets so as to provide mobile cloud computing service under a vehicle networking environment. The article “Device-to-Device-Based Heterogeneous Radio Access Network Architecture for Mobile Cloud Computing” studied another wireless networking scenario. In this case, a static cloud collaborates with a mobile dynamic cloud through a cloudlet. Last but not least, cloudlets can also be applied for supporting Internet of Things. The article “Edge Analytics in the Internet of Things” presented Gigasight, which is a cloudlet-based video analytic system.We hope that this issue of Cloud-Link can provide you with useful references to explore this important and interesting topic further. Articles have been selected based on various considerations (for example, variety, relevancy, and anticipated readers’ interests) and unavoidably there are many other useful and insightful articles that have not been included. You are also encouraged to search through IEEE Xplore and other databases for further reading.
We are looking for topics for upcoming issues. If you have any suggestions, please email them to firstname.lastname@example.org.
Henry Chan, Victor Leung, Jens Jensen, and Tomasz Wiktorski
Min Chen, Yixue Hao, Yong Li, Chin-Feng Lai, and Di Wu
Published in IEEE Communications Magazine, June 2015
As mobile devices are equipped with more memory and computational capability, a novel peer-to-peer communication model for mobile cloud computing is proposed to interconnect nearby mobile devices through various short range radio communication technologies to form mobile cloudlets, where every mobile device works as either a computational service provider or a client of a service requester. Though this kind of computation offloading benefits compute-intensive applications, the corresponding service models and analytics tools are remaining open issues. This paper categorizes computation offloading into three modes: remote cloud service mode, connected ad hoccloudlet service mode, and opportunistic ad hoc cloudlet service mode. We also conduct a detailed analytic study for the proposed three modes of computation offloading at ad hoc cloudlet.
Yang Zhang, Dusit Niyato, and Ping Wang
Published in IEEE Transactions on Mobile Computing, February 2015
The emergence of mobile cloud computing enables mobile users to offload applications to nearby mobile resource-rich devices (that is, cloudlets) to reduce energy consumption and improve performance. However, due to mobility and cloudlet capacity, the connections between a mobile user and mobile cloudlets can be intermittent. As a result, offloading actions taken by the mobile user might fail (for example, the user moves out of communication range of cloudlets). In this paper, the authors develop an optimal offloading algorithm for the mobile user in such an intermittently connected cloudlet system, considering the users’ local load and availability of cloudlets. They examine users’ mobility patterns and cloudlets’ admission control, and derive the probability of successful offloading actions analytically. They formulate and solve a Markov decision process (MDP) model to obtain an optimal policy for the mobile user with the objective to minimize the computation and offloading costs. Furthermore, they prove that the optimal policy of the MDP has a threshold structure. Subsequently, they introduce a fast algorithm for energy-constrained users to make offloading decisions. The numerical results show that the analytical form of the successful offloading probability is a good estimation in various mobility cases. Furthermore, the proposed MDP offloading algorithm for mobile users outperforms conventional baseline schemes.
Laura Toni, Gene Cheung, and Pascal Frossard
Published in IEEE Transactions on Multimedia, May 2016
In multiview applications, camera views can be used as reference views to synthesize additional virtual viewpoints, allowing users to freely navigate within a 3D scene. However, bandwidth constraints might restrict the number of reference views sent to clients, limiting the quality of the synthesized viewpoints. In this work, the authors study the problem of in-network reference view synthesis aimed at improving the navigation quality at the clients. They consider a distributed cloud network architecture, where data stored in a main cloud is delivered to end users with the help of cloudlets, that is, resource-rich proxies close to the users. They argue that, in case of limited bandwidth from the cloudlet to the users, resampling at the cloudlet the viewpoints of the 3D scene (that is, synthesizing novel virtual views in the cloudlets to be used as new references to the decoder) is beneficial compared to mere subsampling of the original set of camera views. The authors therefore cast a new reference view selection problem that seeks the subset of views minimizing the distortion over a view navigation window defined by the user under bandwidth constraints. They prove that the problem is NP-hard, and they propose an effective polynomial time algorithm using dynamic programming to solve the optimization problem under general assumptions that cover most of the multiview scenarios in practice. Simulation results confirm the performance gain offered by virtual view synthesis in the network.
Yang Chen, Yu Chen, Qiang Cao, and Xiaowei Yang
Published in IEEE Transactions on Parallel and Distributed Systems, March 2016
The Internet was designed with the end-to-end principle where the network layer provided merely the best-effort forwarding service. This design makes it challenging to add new services into the Internet infrastructure. However, as the Internet connectivity becomes a commodity, users and applications increasingly demand new in-network services. This paper proposes PacketCloud, a cloudlet-based open platform to host in-network services. Different from standalone, specialized middleboxes, cloudlets can efficiently share a set of commodity servers among different services, and serve the network traffic in an elastic way. PacketCloud can help both Internet Service Providers (ISPs) and emerging application/content providers deploy their services at strategic network locations. The authors have implemented a proof-of-concept prototype of PacketCloud. PacketCloud introduces a small additional delay, and can scale well to handle high-throughput data traffic. They have evaluated PacketCloud in both a fully functional emulated environment, and the real Internet.
Hongli Zhang, Qiang Zhang, and Xiaojiang Du
Published in IEEE Transactions on Vehicular Technology, December 2015
Mobile cloud computing is an emerging technology for facilitating complex application execution on smartphones. Cloud services are utilized not only to speed up the running of mobile applications but to save energy for smartphones as well. In this paper, the authors propose to combine the vehicular cloud with the infrastructure-based cloud to expand the current available resources for task requests from smartphones. In their proposed architecture, the vehicular cloud acts as a cloud-service provider for smartphones. Moreover, they propose a flexible offloading strategy (FOS) to carry out task migration. The vehicular cloud is able to discover and utilize the underutilized resources in vehicles to accomplish application offloading for smartphones. The FOS estimates the efficiency of various cloud service providers based on current resource conditions and then selects the suitable cloud service provider to perform the requested task. Experimental results show that the proposed approach can improve the performance of mobile applications on smartphones in terms of task response time and energy consumption.
Minho Jo, Taras Maksymyuk, Bohdan Strykhalyuk, and Choong-Ho Cho
Published in IEEE Wireless Communications, June 2015
The emerging heterogeneous mobile network architecture is designed for an increasing amount of traffic, quality requirements, and new mobile cloud computing demands. This article proposes a hierarchical cloud computing architecture to enhance performance by adding a mobile dynamic cloud formed by powerful mobile devices to a traditional general static cloud. A mobile dynamic cloud is based on heterogeneous wireless architecture where device-to-device communication is used for data transmission between user devices. The main advantage of the proposed architecture is an increase in overall capacity of a mobile network through improved channel utilization and traffic offloading from Long Term Evolution-Advanced to device-to-device communication links. Simulations show that the proposed architecture increases the capacity of a mobile network by up to 10 percent depending on the conditions and amount of offloaded data. The offloading probability is also evaluated by taking into consideration the number of devices in the cloudlet and the content matching values. The authors have gained insight into how content similarity affects offloading probability much more than the number of devices in a cloudlet.
Mahadev Satyanarayanan, Pieter Simoens, Yu Xiao, Padmanabhan Pillai, Zhuo Chen, Kiryong Ha, Wenlu Hu, and Brandon Amos
Published in IEEE Pervasive Computing, April-June 2015
High-data-rate sensors, such as video cameras, are becoming ubiquitous in the Internet of Things. This article describes GigaSight, an Internet-scale repository of crowd-sourced video content, with strong enforcement of privacy preferences and access controls. The GigaSight architecture is a federated system of VM-based cloudlets that perform video analytics at the edge of the Internet, thus reducing the demand for ingress bandwidth into the cloud. Denaturing, which is an owner-specific reduction in fidelity of video content to preserve privacy, is one form of analytics on cloudlets. Content-based indexing for search is another form of cloudlet-based analytics. This article is part of a special issue on smart spaces.