Internet of Things (IoT) is featured with its seamless connectivity of billions of smart devices, which offer different functionalities and serve various personalized tasks. To meet the task-specific requirements such as latency and privacy, the fog computing emerges to extend cloud computing services to the edge of the Internet backbone. This paper deals with online fog computing emerging in IoT, where the goal is to balance computation and communication at fog networks on-the-fly to minimize service latency. Due to heterogeneous devices and human participation in IoT, the online decisions here need to flexibly adapt to the temporally unpredictable user demands and availability of fog resources. By generalizing the classic online convex optimization (OCO) framework, the low-latency fog computing task is first formulated as an OCO problem involving both time-varying loss functions and time-varying constraints. These constraints are revealed after making decisions, and allow instantaneous violations yet they must be satisfied in the long term. Tailored for heterogeneous tasks in IoT, a 'thing-adaptive' online saddle-point (TAOSP) scheme is developed, which automatically adjusts the stepsize to offer desirable task-specific learning rates. It is established that without prior knowledge of the time-varying parameters, TAOSP simultaneously yields near-optimality and feasibility, provided that the best dynamic solutions vary slowly over time. Numerical tests corroborate that our novel approach outperforms the state-of-the-art in minimizing network latency.
Bibliographical noteFunding Information:
This work was supported in part by the NSF under Grant 1509040, Grant 1508993, and Grant 1711471, in part by NSF China under Grant 61573331, and in part by NSF Anhui under Grant 1608085QF130
Manuscript received January 3, 2018; revised May 30, 2018; accepted July 22, 2018. Date of publication July 26, 2018; date of current version January 16, 2019. This work was supported in part by the NSF under Grant 1509040, Grant 1508993, and Grant 1711471, in part by NSF China under Grant 61573331, and in part by NSF Anhui under Grant 1608085QF130. This paper was presented in part at the IEEE Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA, Oct. 29–Nov. 1, 2017 . (Corresponding author: Georgios B. Giannakis.) T. Chen, Y. Shen, and G. B. Giannakis are with the Department of Electrical and Computer Engineering and the Digital Technology Center, University of Minnesota, Minneapolis, MN 55455 USA (e-mail: email@example.com; firstname.lastname@example.org; email@example.com).
© 2014 IEEE.
- Heterogeneous tasks
- Internet of Things (IoT)
- Mobile edge computing
- Online learning
- Saddle-point method