The widespread demand for high rate multimedia wireless communications has drastically increased the power consumption of wireless networks. However, the advances in battery technology have not kept pace, resulting in a severe mismatch between the energy thirst and battery capacity of mobile units. The major objective of this research is to develop energy-efficient techniques for robust and secure wireless networks through distributed optimization of cross-layer network design.
This research performs a comprehensive investigation into energy-efficient wireless communications. In wireless networks, the channel conditions of users, at different locations, times, and frequencies are different. The quality of service and network efficiency can be significantly improved if these differences can be exploited. Since all protocol layers impact energy consumption, the investigators will develop cross-layer energy-efficient techniques to reduce redundant message transfers and the associated energy consumption. This research will focus on energy-efficient transmission and resource allocation strategies that are amenable to applications in wireless OFDM and MIMO systems, and emphasize energy efficiency over peak rates. To enhance energy efficiency for wireless networks, novel approaches and techniques based on new performance criteria for integrative network optimization will be investigated. Key energy considerations for developing cross-layer network media access protocols and resource allocation algorithms will be integrated into the new framework.
During the period of the NSF grant, we have investigated various energy efficiency (EE) design problems, such as EE design in OFDMA, MIMO, distributed antenna systems (DAS), relaying, and HetNets, and have achieved fruitful research findings. In total, we have published/submitted 17 journal papers and 16 conference papers. We have given presentations and tutorials at IEEE conferences. We have created a website for public access of our research findings. Our research findings cover broad areas of wireless communications, espicially in PHY and MAC layers, and can be roughly divided into the following six categories: -EE survey, tutorial and open issues (2 journal papers) -EE design in OFDMA (7 journal papers and 7 conference papers) -EE transmission in relay/cooperative systems (2 journal papers and 2 conference papers) -EE enhancement in MIMO (3 journal papers and 3 conference papers) -EE design in DAS (2 journal papers) -Others EE topics (HetNet, fundamental issues .etc) (1 journal paper and 2 conference papers) With all the research findings in these areas, we have revealed the fundamental properties and the benefits of EE design and shown how to improve EE in wireless communications through cross-layer optimization. Our research findings have made significant impact on EE wireless communication and have been highly acknowledged and cited by the IEEE community. For example, our two survey papers "A survey of energy-efficient wireless communications" and "Energy-efficient wireless communications: tutorial, survey, and open issues" have both been recommended as one of the "Best Reading Topics on Green Communications" by IEEE via www.comsoc.org/best-readings/topics/green. Our paper "Energy efficiency of cooperative beamforming in wireless ad-hoc networks" has been awarded the Best Paper Award at IEEE 2012 International Communications Conferences (ICC'12). In addition, our research findings have also inspired the engineering/industry field of wireless communications. Our research findings also contributes to the reduction of energy consumption and hazardous battery waste. It will help to build a clean and green energy future and makes our wireless communications environmentally sustainable.
