Energy efficient cooperative relaying and cognitive radio technologies to deliver green communication

So far, achieving high data rate has been the primary focus of research in wireless communication systems, without much consideration of energy efficiency. However, many of communication technologies significantly increase system complexity and energy consumption. In addition to the environmental problems that the governments restrict the greenhouse gases and pollution, energy costs also contribute a significant part of network operator´s overall expenditures due to the rapidly growing demand for mobile communication. Therefore, energy saving approaches are urgently required by both governments and network venders. Escalating energy costs and environmental concerns have already created an urgent need for more energy-efficient wireless communication. To address the challenge of increasing power efficiency in wireless networks and thereby to maintain profitability, this paper will discuss some research issues and challenges and suggest some paradigm-shifting technologies to enable an energy efficient or green cellular network.