Characterizing Energy-Delay Tradeoff in GREEN Communications


Characterizing Energy-Delay Tradeoff in GREEN Communications

Thu, 20/09/2012 - 13:45 to 15:30


Prof Zhisheng Niu, Tsinghua National Lab for Information Science and Technology, Tsinghua University

Characterizing Energy-Delay Tradeoff in GREEN Communications

Zhisheng Niu, Jian Wu, Xueying Guo, Jianan Zhang, Sheng Zhou
Electronic Engineering Department, Tsinghua University
Tsinghua National Lab for Information Science and Technology

Abstract: One of the key approaches to make the communication networks more GREEN (Globally Resource-optimized and Energy-Efficient Networks) is to have the network architecture and resources more adaptive to the traffic variations, including making some lightly-loaded base stations (BSs) go to sleep. This is the concept of so-called TANGO (Traffic-Aware Network planning and Green Operation) published by the author earlier. To realize this, some delay-insensitive users may have to experience some delay or other kind of QoS degradation when traffic load is high in order to save energy, i.e., energy can be traded off by some delay. The fundamental question then arises: how much energy can be traded off by how long delay?

In this talk, we characterize the tradeoffs between energy consumption and service delay in a base station with sleep mode operations by queueing models. The base station is modeled as an M/G/1 vacation queue with setup and close-down times, where the base station enters sleep mode if no customers arrive during the close-down time after the queue becomes empty and it starts to setup when it sees N arriving customers during its sleep period. Several closed-form formulas are derived to demonstrate the tradeoffs between the energy consumption and the mean delay by changing the close-down time and N. It is shown that the relationship between the energy consumption and the mean delay is linear. Besides, larger N may lead to lower energy consumption, but there exists N that minimizes the mean delay. We also investigate the maximum delay for certain percentage of service, which is closely related to the mean delay. In summary, the closed-form tradeoffs cast light on designing BS sleep control policies which aim to save energy while maintaining acceptable quality of service.


Zhisheng Niu graduated from Northern Jiaotong University (currently Beijing Jiaotong University), Beijing, China, in 1985, and got his M.E. and D.E. degrees from Toyohashi University of Technology, Toyohashi, Japan, in 1989 and 1992, respectively. After spending two years at Fujitsu Laboratories Ltd., Kawasaki, Japan, he joined with Tsinghua University, Beijing, China, in 1994, where he is now a professor at the Department of Electronic Engineering and the deputy dean of the School of Information Science and Technology. His major research interests include queueing theory, traffic engineering, mobile Internet, radio resource management of wireless networks, and green communication and networks.
Dr. Niu has been an active volunteer for various academic societies, including council member of Chinese Institute of Electronics (2006-10), vice chair of the Information and Communication Network Committee of Chinese Institute of Communications (2008-12), Councilor of IEICE-Japan (2009-11), and membership development coordinator of IEEE Region 10 (2009-10). In particular, in IEEE Communication Society, he has been serving as an editor of IEEE Wireless Communication Magazine (2009-12), director of Asia-Pacific Region (2008-09), director for Conference Publications (2010-11), chair of Beijing Chapter (2001-08), and members of Award Committee (2011-13), Emerging Technologies Committee (2010-12), On-line Content Committee (2010-12), and Strategy Planning Committee. He has also been serving as general co-chairs of APCC’09/WiCOM’09, TPC co-chairs of APCC’04/ICC’08/WOCC’10/ICCC’12, panel co-chair of WCNC’10, tutorial co-chairs of VTC’10-fall/Globecom’12, and publicity co-chairs of PIMRC’10/WCNC’02. He was the guest co-editors of the IEEE Wireless Communication Magazine Special Issue on Green Radio Communications and Networks (published on Oct. 2011) and the Communication Networks Special Issue on Green Communication Networks (to be published in 2012).
Prof. Niu received the Best Paper Awards from the 13th and 15th Asia-Pacific Conference on Communication (APCC) in 2007 and 2009, respectively, and Outstanding Young Researcher Award from Natural Science Foundation of China in 2009. He is now the Chief Scientist of the National Fundamental Research Program (so called “973 Project”) of China "Fundamental Research on the Energy and Resource Optimized Hyper-Cellular Mobile Communication System" (2012-2016), which is the first national project green communications in China. He is the fellow of IEEE and IEICE, and a distinguished lecturer of IEEE Communication Society (2012-13).