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

Energy efficiency perspectives of PMR networks

Recently, the concern about energy efficiency in wireless communications has been growing rapidly. Manufacturers and researchers have developed innovative solutions, highlighting the benefits in reducing operational expenditures (OPEX) and carbon footprint. Professional Mobile Radio (PMR) systems, like Terrestrial Trunked Radio (TETRA), have been designed to provide voice and data services to professional users. The energy consumption is one of the critical aspects of PMR broadband solutions and a major constraint for PMR services. The future convergence of PMR to the LTE system introduces a new topic in the research discussion about the energy efficiency of wireless systems. This paper focuses on the feasibility of energy efficient solutions for current and potentially future PMR networks, by providing a mathematical formulation of power consumption in TETRA base stations and assessing possible business models and energy saving solutions for enhanced mission-critical operations. The energy efficiency evaluation has been performed by taking into account the traffic load of a deployed TETRA regional network: in the considered network scenario with 150 base stations, significant OPEX savings up to 70 thousand Euros per year of operation are achieved. Moreover, the proposed solutions allow for saving more than 1 ton of CO 2 per year

Energy Management in LTE Networks

Wireless cellular networks have seen dramatic growth in number of mobile users. As a result, data requirements, and hence the base-station power consumption has increased significantly. It in turn adds to the operational expenditures and also causes global warming. The base station power consumption in long-term evolution (LTE) has, therefore, become a major challenge for vendors to stay green and profitable in competitive cellular industry. It necessitates novel methods to devise energy efficient communication in LTE. Importance of the topic has attracted huge research interests worldwide. Energy saving (ES) approaches proposed in the literature can be broadly classified in categories of energy efficient resource allocation, load balancing, carrier aggregation, and bandwidth expansion. Each of these methods has its own pros and cons leading to a tradeoff between ES and other performance metrics resulting into open research questions. This paper discusses various ES techniques for the LTE systems and critically analyses their usability through a comprehensive comparative study

Powering remote area base stations by renewable energy

Abstract. The number of cellular subscriptions have seen a tremendous growth in the last decade and to provide connectivity for everyone has led to growth in number of base stations (BSs). BSs installed at places where reliable grid power is not available has increased and will continue to increase in the coming years to connect everybody on the globe. Energy and cost efficiency is becoming a criterion of ever increasing importance in the information and communication technology sector. Energy and cost efficiency is especially important for remote areas where providing mobile communication services is inhibited by the economic drawback of low revenue potential. In this thesis, we discuss the role of BS power consumption in the cellular networks in order to investigate approaches to lower the overall power consumption of the cellular network. The thesis covers structure of a BS and the power consumption of its components. Previous works and research approaches proposed to reduce the power consumption of BSs and to what extent they can lower the power requirement are discussed. Reducing the BS power consumption will reduce the operating cost for the networks and ease the deployment of BSs in remote areas. Also discussed are the two key technical features of 5th generation cellular access networks (beam forming through massive multiple input multiple output antenna systems and ultra-lean system design) that are promising in terms of reducing the BS power consumption. Furthermore, we discuss viable sources of renewable energy that can be used to power BSs in the remote areas. An overview of the renewable energy resources that can be used for this purpose (solar and wind energy) and their availability in different regions is discussed. The setups for harnessing solar and wind energy to generate power are presented in this thesis. For different cases requirements of wind and solar energy systems to power the BSs are calculated. Results show that while solar energy alone is a feasible option in regions at low latitude, small solar energy systems of 4–7 kW rated output power can easily power BS during the entire year. But in regions of high latitude using solar energy alone cannot meet the BS power requirement as there are long durations of very low or negligible solar irradiation levels. Furthermore, the energy produced by small wind energy setups at different wind speeds is investigated for the purpose of powering BSs. We discuss the range of windspeed levels for which the energy produced is sufficient to power a BS. Areas with average windspeeds of 5–8 m/s are very suitable for using wind energy as a source of power for BSs. Hybrid energy systems to power BSs and also a few energy storage options to store excess power are also discussed in this thesis