Green Cellular Networks: A Survey, Some Research Issues and Challenges

Energy efficiency in cellular networks is a growing concern for cellular operators to not only maintain profitability, but also to reduce the overall environment effects. This emerging trend of achieving energy efficiency in cellular networks is motivating the standardization authorities and network operators to continuously explore future technologies in order to bring improvements in the entire network infrastructure. In this article, we present a brief survey of methods to improve the power efficiency of cellular networks, explore some research issues and challenges and suggest some techniques to enable an energy efficient or "green" cellular network. Since base stations consume a maximum portion of the total energy used in a cellular system, we will first provide a comprehensive survey on techniques to obtain energy savings in base stations. Next, we discuss how heterogeneous network deployment based on micro, pico and femto-cells can be used to achieve this goal. Since cognitive radio and cooperative relaying are undisputed future technologies in this regard, we propose a research vision to make these technologies more energy efficient. Lastly, we explore some broader perspectives in realizing a "green" cellular network technologyComment: 16 pages, 5 figures, 2 table

Strategies for shifting technological systems : the case of the automobile system

Californian and Dutch efforts to produce electric vehicles are explored and compared. Three strategies are put forward that could turn electric vehicles from an elusive legend, a plaything, into a marketable product: technology forcing creating a market of early promises, experiments geared towards niche development and upscaling (strategic niche management), and the creation of new alliances (technological nexus) which bring technology, the market, regulation and many other factors together. These strategies deployed in the Californian and Dutch context are analysed in detail to explore their relative strengths and weaknesses and to argue in the end that a combined use of all three will increase the chances that the dominant technological system will change. The succesful workings of these strategies crucially depend on the coupling of the variation and selection processes, building blocks for any evolutionary theory of technical change. Evolutionary theory lacks understanding of these coupling processes. Building on recent insights from the sociology of technology, the authors propose a quasi-evolutionary model which underpins the analysis of suggested strategies

A survey and tutorial of electromagnetic radiation and reduction in mobile communication systems

This paper provides a survey and tutorial of electromagnetic (EM) radiation exposure and reduction in mobile communication systems. EM radiation exposure has received a fair share of interest in the literature; however, this work is one of the first to compile the most interesting results and ideas related to EM exposure in mobile communication systems and present possible ways of reducing it. We provide a comprehensive survey of existing literature and also offer a tutorial on the dosimetry, metrics, international projects as well as guidelines and limits on the exposure from EM radiation in mobile communication systems. Based on this survey and given that EM radiation exposure is closely linked with specific absorption rate (SAR) and transmit power usage, we propose possible techniques for reducing EM radiation exposure in mobile communication systems by exploring known concepts related to SAR and transmit power reduction in mobile systems. Thus, this paper serves as an introductory guide to EM radiation exposure in mobile communication systems and provides insights toward the design of future low-EM exposure mobile communication networks