Title: How Densely Should the Data Base Stations be Deployed in Hyper-Cellular Networks?
Tsinghua National Lab for Information Science and Technology
Tsinghua University, Beijing 100084, China
Abstract: One of the key approaches to make the mobile communication networks more GREEN (Globally Resource-optimized and Energy-Efficient Networks) is to have the cellular architecture and radio resource allocation more adaptive to the environment and 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) and CHORUS (Collaborative and Harmonized Open Radio Ubiquitous Systems) published by the author earlier. To realize this, a new cellular framework, named hyper-cellular networks (HCN), has been proposed, in which the coverage of control signals is decoupled from the coverage of data signals so that the data coverage can be more elastic in accordance with the dynamics of traffic characteristics and QoS requirements. Specifically, the data base stations (DBSs) in HCN can be densely deployed during peak traffic time in order to satisfy the capacity requirement, while a portion of DBSs can be switched off or go to sleep mode if the traffic load is lower than a threshold in order to save energy. A fundamental question then arises: how densely should the DBSs be deployed in order to balance the QoS requirements and the energy consumption in hyper cellular networks?
In this talk, we characterize the optimal DBS density for both homogeneous and heterogeneous hyper cellular networks to minimize network cost with stochastic geometry theory. For homogeneous cases, both upper and lower bounds of the optimal DBS density are derived. For heterogeneous cases, our analysis reveals the best type of DBSs to be deployed for capacity extension or to be switched off for energy saving. Specifically, if the ratio between the micro DBS cost and the macro DBS cost is lower than a threshold, which is a function of path loss and their transmit power, then the optimal strategy is to deploy micro DBSs for capacity extension or to switch off macro DBSs (if possible) for energy saving with higher priority. Otherwise, the optimal strategy is the opposite. Based on the parameters from EARTH, numerical results show that in the dense urban scenario, compared to the traditional macro-only homogeneous cellular network with no DBS sleeping, deploying micro DBSs can reduce about 40% of the total energy cost, and further reduce about 20% with DBS sleeping capability.
Biography: 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.
Prof. Niu is a co-recipient of the Best Paper Awards from the 13th and 15th Asia-Pacific Conference on Communication (APCC) in 2007 and 2009, respectively, and received 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).