Toward transcoding as a service: energy-efficient offloading policy for green mobile cloud
Toward transcoding as a service: energy-efficient offloading policy for green mobile cloud
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DOI：
10.1109/mnet.2014.6963807
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发表时间：
2014-11
期刊：
影响因子：
9.3
通讯作者：
Weiwen Zhang;Yonggang Wen
中科院分区：
文献类型：
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作者：
Weiwen Zhang;Yonggang Wen
在这篇文章中，我们研究了一个通用的移动的云系统中的转码即服务（TaaS）的节能卸载策略。移动的设备上的计算可以卸载到移动的云系统，该系统由前端的调度器和后端的一组服务引擎组成。特别地，转码任务可以在移动终端上执行（即，移动的执行）或者由调度器卸载并调度到云中的服务引擎之一（即，云执行）。我们的目标是最大限度地减少移动终端和云中服务引擎上的转码能耗，同时实现低延迟。对于移动终端，我们将其在延迟截止期限下的卸载策略转化为一个约束优化问题。我们发现了一个操作区域，在该区域上，执行模式，即移动的执行或云执行，对于移动终端来说更节能。对于云，我们提出了一个在线算法来分配转码任务的服务引擎，以减少能源消耗，同时实现队列稳定性的目标。通过合理选择控制变量，该算法的性能优于其他算法，具有较低的时间平均能耗和时间平均队列长度的服务引擎。提出的分载策略可以同时降低移动的设备和云的能耗，为绿色移动的云的设计提供了指导。
In this article we investigate energy-efficient offloading policy for transcoding as a service (TaaS) in a generic mobile cloud system. Computation on mobile devices can be offloaded to a mobile cloud system that consists of a dispatcher at the front end and a set of service engines at the back end. Particularly, a transcoding task can be executed on the mobile device (i.e. mobile execution) or offloaded and scheduled by the dispatcher to one of the service engines in the cloud (i.e. cloud execution). We aim to minimize the energy consumption of transcoding on the mobile device and service engines in the cloud while achieving low delay. For the mobile device, we formulate its offloading policy under delay deadline as a constrained optimization problem. We find an operational region on which execution mode, that is, mobile execution or cloud execution, is more energy efficient for the mobile device. For the cloud, we propose an online algorithm to dispatch transcoding tasks to service engines, with an objective to reduce energy consumption while achieving queue stability. By appropriately choosing the control variable, the proposed algorithm outperforms alternative algorithms, with lower time average energy consumption and time average queue length on the service engines. The proposed offloading policy can reduce energy consumption on both mobile devices and the cloud jointly, which provides guidelines for the design of green mobile cloud.